Medical Policy: 02.04.16 

Original Effective Date: March 2008 

Reviewed: September 2020 

Revised: September 2020 

 

Notice:

This policy contains information which is clinical in nature. The policy is not medical advice. The information in this policy is used by Wellmark to make determinations whether medical treatment is covered under the terms of a Wellmark member's health benefit plan. Physicians and other health care providers are responsible for medical advice and treatment. If you have specific health care needs, you should consult an appropriate health care professional. If you would like to request an accessible version of this document, please contact customer service at 800-524-9242.

 

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This Medical Policy document describes the status of medical technology at the time the document was developed. Since that time, new technology may have emerged or new medical literature may have been published. This Medical Policy will be reviewed regularly and be updated as scientific and medical literature becomes available.

 

Description:

This policy does not address circulating tumor DNA for the management of non-small cell lung cancer, see medical policy 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer (Liquid Biopsy).

 

Circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) in peripheral blood, are referred to as “liquid biopsy.”  A liquid biopsy is the analysis of circulating tumor DNA (ctDNA) or circulating tumor cells (CTCs) as methods of noninvasively characterizing tumors and tumor genome from the peripheral blood. Liquid biopsies have several potential uses for guiding therapeutic decisions in patients with advanced cancers: determine if a specific treatment is indicated; may be performed to help identify indicators of disease recurrence or disease progression, or being screened for cancer.

 

Circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) potentially offer a noninvasive alternative to tissue biopsy.  Liquid biopsy for NSCLC is further addressed in medical policy 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer.

 

Circulating Tumor DNA (ctDNA)

Normal tumor cells release small fragments of DNA into the blood, which is referred to as cell-free DNA (cfDNA). Cell-free DNA from nonmalignant cells is released by apoptosis. Most cell-free tumor DNA is derived from apoptotic and/or necrotic tumor cells, either from the primary tumor, metastases or CTCs (circulating tumor cells). Unlike apoptosis, necrosis is considered a pathologic process and generates larger DNA fragments due to incomplete and random digestion of genomic DNA. The length or integrity of the circulating DNA can potentially distinguish between apoptotic and necrotic origin. Circulating tumor DNA (ctDNA) can be used for genomic characterization of the tumor.

 

Circulating Tumor Cells (CTCs)

Intact circulating tumor cells (CTCs) are released from a primary tumor and/or metastatic site into the bloodstream. The half-life of a CTC in the bloodstream is short (1-2 hours), and CTCs are cleared through extravasation into secondary organs. Most assays detect CTCs through the use of surface epithelial markers such as EpCAM and cytokeratins. The primary reason for detecting CTCs is prognostic, through quantification of circulating levels which could potentially provide information that could guide treatment decisions or aid in the monitoring of response to treatment.

 

The below table summarizes some commercially available liquid biopsy tests, and this list may not be comprehensive:

 

Circulating Tumor DNA (ctDNA) and Circulating Tumor Cells (CTCs) (Liquid biopsy) Tests
TestManufacturerType of Liquid Biopsy
CancerIntercept: Breast, ovarian, lung, colorectal, melanoma, head and neck, pancreatic, thyroid, prostate, stomach. Pathway Genomics ctDNA Circulating Tumor DNA
CellMax-First Sight CRC Colorectal Cancer Early Detection Test: used as a screening test for colorectal cancer. Detects pre-cancer and early stage cancer. CellMax Life CTC Circulating Tumor Cells
CellMax-LBx Liquid Biopsy: Diagnosed solid tumor for targeted therapy selection. CellMax Life CTC Circulating Tumor Cells plus ctDNA Circulating Tumor DNA
CellMax-PanCa Monitoring Test: Diagnosed solid tumor for treatment effectiveness and early recurrence. CellMax Life CTC Circulating Tumor Cells
CellMax-Prostate Cancer Test: To reduce unnecessary biopsies in PSA gray zone patients. CellMax Life CTC Circulating Tumor Cells
CellSearch System: Aids in the monitoring of patients with metastatic breast, prostate or colorectal cancer and allows assessment of patient prognosis and is predictive of progression-free survival and overall survival. Informs clinical decision making. Janssen Diagnostics formerly Veridex CTC Circulating Tumor Cells
Circulogene Liquid Biopsy Test: Provides information on current FDA-approved treatment options for the tumor DNA identified. Doctor can monitor tumor responsiveness and adjust treatment protocols. Theranostics ctDNA Circulating Tumor DNA

ClearID Biomarker Expression Assays: For PD-L1 and HER2.

Note: ClearID test results are summarized in an actionable genomic report containing clinical interpretations of the identified biomarkers and variants, their associations with drugs, related clinical trials, and experimental therapies that can help guide physicians, oncologists, and pathologists in making treatment decisions

Cynvenio CTC Circulating Tumor Cells plus ctDNA Circulating Tumor DNA

ClearID Breast Cancer: Optimized for breast cancer, also used for stomach, skin and prostate cancer.

Note: ClearID test results are summarized in an actionable genomic report containing clinical interpretations of the identified biomarkers and variants, their associations with drugs, related clinical trials, and experimental therapies that can help guide physicians, oncologists, and pathologists in making treatment decisions

Cynvenio CTC Circulating Tumor Cells plus ctDNA Circulating Tumor DNA

ClearID Lung Cancer: Optimized for non-small cell lung cancer, also used for head and neck cancers, and other thoracic cancers

Note: ClearID test results are summarized in an actionable genomic report containing clinical interpretations of the identified biomarkers and variants, their associations with drugs, related clinical trials, and experimental therapies that can help guide physicians, oncologists, and pathologists in making treatment decisions

Cynvenio CTC Circulating Tumor Cells plus ctDNA Circulating Tumor DNA

ClearID Solid Tumor Panel: Optimized for colon and bladder cancer, also used for other solid tumor cancers.

Note: ClearID test results are summarized in an actionable genomic report containing clinical interpretations of the identified biomarkers and variants, their associations with drugs, related clinical trials, and experimental therapies that can help guide physicians, oncologists, and pathologists in making treatment decisions.

Cynvenio CTC Circulating Tumor Cells plus ctDNACirculating Tumor DNA
Colvera: Identifies the presence of two methylated genes, BCAT1 and IKZF1, when present show a high concordance of colorectal cancer recurrence. Clinical Genomics ctDNA Circulating Tumor DNA
FoundationOne Liquid CDx: Analyzes 324 genes, plus it reports blood tumor mutational burden (bTMB), microsatellite instability (MSI) and tumor fraction values. Results can help guide therapy selection and identify clinical trial options for patients with solid tumors. Foundation Medicine ctDNA Circulating Tumor DNA

Guardant360: For advanced solid tumors, does not predict chemotherapy response but provides information on the genomic alterations known to respond to specific targeted therapies to the doctor the opportunity to tailor treatment to the individual cancer.

  • Point Mutations (SNVs) (73 genes)
  • Indels (23 genes)
  • Amplifications (18 genes)
  • Fusions (6 genes)

Note: Guardant360 version updated to Guardant360 CDx

Guardant Health ctDNA Circulating Tumor DNA

Guardant360 CDx: Is a qualitative next generation sequencing-based in virto diagnostic device that uses targeted high throughput hybridization-based capture technology for detection of single nucleotide variants (SNVs), insertions and deletions (indels) in 55 genes, copy number amplifications (CNAs) in 2 genes and fusions in 4 genes. Guradant360 CDx utilizes circulating cell-free DNA (cfDNA) from plasma of peripheral whole blood collected in Streck Cell-Free DNA Blood Collection Tubes (BCTs).

 

The test in intended to be used as a companion diagnostic to identify non-small cell lung cancer (NSCLC) patients who may benefit from treatment with targeted therapy in accordance with approved therapeutic product labeling:


The test in intended to be used as a companion diagnostic to identify non-small cell lung cancer (NSCLC) patients who may benefit from treatment with targeted therapy in accordance with approved therapeutic product labeling:

 

BiomarkerTherapy
EGFR exon 19 deletions, L858R and T790M Tagrisson (Osimertinib)

 

Guardant360 CDx was FDA approved August 2020

Guardant Health crDNA
IVDiagnostics: Used for patients with metastatic advanced staged cancers: breast, lung, ovarian, prostate, colorectal, kidney, melanoma, and pancreatic. Detect and monitor for circulating tumor cells that can cause metastases to rapidly detect and monitor for these cells to inform therapeutic approaches. Velox CTC Circulating Tumor Cells
LiquidGx: Solid tumor therapies, monitoring for drug resistance markers. Admera Health ctDNA Circulating Tumor DNA
OncoBEAM for Colorectal Cancer: To assist in treatment decisions for metastatic colorectal cancer. Sysmex Inostics ctDNA Circulating Tumor DNA
OncoBEAM for Melanoma: To assist in treatment decisions for melanoma. Sysmex Inostics ctDNA Circulating Tumor DNA

Oncotype DX AR-V7 Nucleus Detect: Is intended for use in patients with metastatic castration-resistant prostate cancer (mCRPC) who are considering androgen receptor signaling inhibitors (e.g. abiraterone, enzalutamide). The tests identifies the presence of AR-V7 protein in the nucleus of circulating tumor cells (CTCs) in the blood to inform clinical decision-making.

Eligibility Criteria: have confirmed mCRPC; have received and failed AR-targeted therapy; and are considering additional AR-targeted therapies

The results are reported as either AR-V7+ (positive) or AR-V7- (negative)

Genomic Health, Inc. CTC Circulating Tumor Cells
PlasmaSelect 64: Multiple cancer types, provides clinical explanation of all reported alterations, including FDA approved therapies, clinical trials and published literature. Personal Genome Diagnostics ctDNA Circulating Tumor DNA
Signatera for Bladder, Breast, and Colon: is a custom-built circulating tumor DNA (ctDNA) test for treatment monitoring and molecular residual disease (MRD) assessment in patients previously diagnosed with cancer. It is not intended to match patients with any particular therapy. Rather, it is intended to detect and quantify how much cancer is left in the body, to detect recurrence earlier, and to help optimize treatment decisions. Natera, Inc ctDNA
Target Selector: For breast, colorectal, gastric, prostate, lung, and melanoma to assist the doctor in understanding the status of the patients disease to make decisions about current and future therapy. Biocept ctDNA Circulating Tumor DNA

 

Treatment Selection

Tissue Biopsy as a Reference Standard

The standard of care (SOC) for treatment selection in advanced solid tumors is biomarker analysis of tissue samples obtained by tissue biopsy. Although tumor testing has been primarily focused on use of formalin-fixed paraffin-embedded (FFPE) tissues, increasingly, laboratories accept other specimen types, notably cytopathology preparations not processed by FFPE methods. Although testing on cell blocks is not included in the FDA approval for multiple companion diagnostic assays, testing on these specimen types is highly recommended when it is the only or best material.

 

While tissue biopsy is required to verify a cancer diagnosis and determine histology, there is often insufficient tissue for genotyping with expert centers reporting rates up to 25%, especially when a gene-by-gene sequential testing approach is utilized. Once tissue is exhausted options include a repeat biopsy or more often treating the patient empirically with standard chemotherapy when the patient may have benefited from targeted therapy.

 

There are various molecular testing methods that may be used to assess for the different genomic biomarkers:

  • Next-generation sequencing (NGS) is used in clinical laboratories. Not all types of alterations are detected by individual NGS assays or combination(s) of assays.
  • It is recommended at this time that when feasible, testing be performed via a broad, panel-based approach, most typically performed by next generation sequencing (NGS). For patients who, in broad panel testing don’t have identifiable driver oncogenes (especially in never smokers), consider RNA-based NGS if not already performed, to maximize detection of fusion events.
  • Real-time polymerase chain reaction (PCR) can be used in a highly targeted fashion (specific mutations targeted). When this technology is deployed, only those specific alterations that are targeted by the assay are assessed.
  • Sanger sequencing requires the greatest degree of tumor enrichment. Unmodified Sanger sequencing is not appropriate for detection of mutations in tumor samples with less than 25% to 30% tumor after enrichment is not appropriate for assays in which identification of subclonal events (e.g. resistance mutations) is important. If Sanger sequencing is utilized, tumor enrichment methodologies are nearly always recommended.
  • Other methodologies may be utilized, including multiplex approaches not listed above (i.e SNaPshot, MassARRAY).
  • Fluorescence in situ hybridization (FISH) analysis is utilized for many assays examining copy number, amplifications, and structural alterations such as gene rearrangements.
  • Immunohistochemistry (IHC) is specifically utilized for some specific analytes and can be useful surrogate or screening assays for others.

 

Cell-free DNA in blood is derived from nonmalignant and malignant cell DNA. The small DNA fragments released into the blood by tumor cells are referred to as circulating tumor DNA (ctDNA). Most ctDNA is derived from apoptotic and necrotic cells, either from the primary tumor, metastases or circulating tumor cells. Unlike apoptosis, necrosis is considered a pathologic process, generating larger DNA fragments due to an incomplete and random digestion of genomic DNA. The length or integrity of the circulating DNA can potentially distinguish between apoptotic and necrotic origins. The ctDNA can be used for genomic characterization of the tumor and identification of the biomarkers of interest. Detection of ctDNA is challenging because cell-free DNA is diluted by nonmalignant circulating DNA and usually represents a small fraction (<1%) of total cell-free DNA. Testing methodology relies on the presence of ctDNA in circulation which is typically analyzed by one of the following methods:

  • Standard testing methodologies such as PCR or sequencing, are used to identify targeted mutations commonly present in tumors of a specific type.
  • Methodologies such as NGS-based sequencing or array-CGH are used to identify both novel and recurrent mutations. These approaches analyze single genes, panels of genes, exomes or genomes. Use of these approaches allows testing with no prior knowledge of genetic mutations that are present in the patient’s tumor.

 

Studies have demonstrated cell-free tumor DNA testing to generally have very high specificity, but significantly compromised sensitivity, with up to 30% false-negative rate.

 

Standards for analytic performance characteristics of cell-free tumor DNA have not been established, and in contrast to tissue-based testing, no guidelines exist regarding the recommended performance characteristics of this type of testing.

 

Selecting Treatment in Advanced Cancers

Clinical Context and Test Purpose

Treatment selection is informed by tumor type, grade, stage, patient performance status, prior treatments, and the molecular characteristics of the tumor such as the presence of driver mutations. One purpose of the liquid biopsy testing of patients who have advanced cancer is to inform a decision regarding treatment selection (e.g. whether to select a targeted a treatment or standard treatment). Patients have traditionally been tested for driver mutations using samples from tissue biopsies.

 

Patients

The target population of patients with advanced cancers for whom the selection of treatment depends on the molecular characterization of the tumor(s).

 

Interventions

The technology being considered is an analysis of tumor genomic biomarkers in peripheral blood (liquid biopsy) using either ctDNA or CTCs tests to determine treatment selection. Several commercial tests are available and many more are in development. In contrast to tissue biopsy, no guidelines exist regarding the recommended performance characteristics of this type of testing. 

 

Both targeted polymerase chain reaction (PCR) based assays and broad next generation sequencing based approaches are available. Patients with negative liquid biopsy results should be reflexed to tumor biopsy testing if they are able to undergo tissue biopsy.

 

Comparators

The relevant comparator of interest is testing for variants using tissue biopsy.

 

The standard of care (SOC) for treatment selection is biomarker analysis of tissue samples obtained by tissue biopsy (formalin-fixed paraffin-embedded (FFPE) tissue). While tissue biopsy is required to verify a cancer diagnosis and determine histology, there is often insufficient tissue for genotyping with expert centers reporting rates up to 25%, especially when a gene-by-gene sequential testing approach is utilized. Once tissue is exhausted options include a repeat biopsy or more often treating the patient empirically with standard chemotherapy when the patient may have benefited from targeted therapy. 

 

Some Guidelines have suggested that testing with a liquid biopsy should be used when testing with tissue biopsy is not feasible. However, studies have demonstrated cell-free tumor DNA testing to generally have very high specificity, but significantly compromised sensitivity, with up to 30% false-negative rate and standards for analytic performance characteristics of cell-free tumor DNA have not been established, and in contrast to tissue-based testing, no guidelines exist regarding the recommended performance characteristics of this type of testing.

 

Outcomes

The outcomes of interest are overall survival (OS) and cancer-related survival. In the absence of direct evidence, the health outcomes of interest are observed indirectly as a consequence of the interventions taken based on the test results.

 

In patients who can undergo tissue biopsy, given that negative liquid biopsy results are reflexed to tissue biopsy, a negative liquid biopsy test (true or false) does not change outcomes compared with tissue biopsy.

 

Similarly, in patients who cannot undergo tissue biopsy, a negative liquid biopsy test (true or false) should result in the patient receiving the same treatment as he/she would have with no liquid biopsy test so a negative liquid biopsy test does not change outcomes.

 

The implications of positive liquid biopsy test results are described below.

 

Potential Beneficial Outcomes

For patients who can undergo tissue biopsy, the beneficial outcomes of a true-positive liquid biopsy result are avoidance of tissue biopsy and its associated complications.

 

For patients who cannot undergo tissue biopsy, the beneficial outcomes of a true-positive liquid biopsy result are receipt of a matched therapy. 

Potential Harmful Outcomes

The harmful outcome of a false-positive liquid biopsy result is incorrect treatment.

 

Studies have demonstrated liquid biopsy (ctDNA/CTC) testing to generally have a high specificity, but significantly compromised sensitivity, with up to 30% false-negative rate.

 

Clinically Valid

Circulating Tumor DNA (ctDNA)

A Test must detect the presence or absence of a condition, the risk of developing a condition in the future, or treatment response (beneficial or adverse).

 

The clinical validity of each commercially available test must be established independently.

 

Much of the literature to date on the use of ctDNA to guide treatment selection is for non-small cell lung cancer, which is addressed in medical policy 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer (Liquid Biopsy), and is not discussed here.

 

Merker et. al (2018) the American Society of Clinical Oncology (ASCO) and College of American Pathologists jointly convened a panel to review the current evidence on the use of circulating tumor DNA (ctDNA) in patients with cancer. The literature search identified 1,338 references to which an additional 31 references were supplied by the expert panel. There were 77 articles selected for inclusion. Their analysis on the evidence on the use of ctDNA states the following: Some ctDNA assays have demonstrated clinical validity and utility with certain types of advanced cancer; however, there is insufficient evidence of clinical validity and utility for the majority of ctDNA assays in advanced cancer. Evidence shows discordance between the results of ctDNA assays and genotyping tumor specimens and supports tumor tissue genotyping to confirm undetected results from ctDNA tests. There is no evidence of clinical utility and little evidence of clinical validity of ctDNA assays in early-stage cancer, treatment monitoring, or residual disease detection. There is no evidence of clinical validity and clinical utility to suggest that ctDNA assays are useful for cancer screening, outside of a clinical trial. Given the rapid pace of research, re-evaluation of the literature will shortly be required, along with the development of tools and guidance for clinical practice.

 

Since the end date of the searches conducted by Merkel et.al. (2018), 4 observational studies of the clinical validity of FoundationOne Liquid CDx (formerly FoundationACT/FoundationOne Liquid) have been published (Table 1). All four studies compared liquid biopsy to tissue biopsy with FoundationOne Liquid CDx comprehensive Genomic testing. Test characteristics are shown in Table 2.  Relevance, design and conduct limitation of these studies are summarized in Tables 3 and 4.

 

Table 1. Study Characteristics of the Cllinical Validity of FoundationOne Liquid CDx
StudyStudy PopulationDesignReference StandardTiming of Reference and Index TestsBlinding of Assessor
Clark et. al. (2018) Patients with advanced cancer Retrospective (tissue) and prospective (liquid biopsy) Tissue biopsy (FoundationOne) 0 to 60 days Not stated
Zhou et. al. (2018) Patients with locally advanced or metastatic solid tumors Retrospective Tissue biopsy (FoundationOne) Not reported; only considered patient with no intervening treatment between liquid and tissue biopsy Not stated
Chung et. al. (2017) Women with estrogen receptor-positive breast cancer Retrospective Tissue biopsy (FoundationOne) 0 to 60 days Not stated
Kim et. al. (2017) Woman with measurable, inoperable, locally advanced or metastatic TNBC previously untreated with systemic therapy Patients were enrolled in a Phase II RCT of Ipataserib plus paclitaxel versus placebo plus paclitaxel Tissue biopsy (FoundationOne) Not reported Not stated

 

RCT: randomized controlled trials; TNBC: triple-negative breast cancer

 

Table 2. Clinical Validity of FoundationOne Liquid CDx

StudyIntial NFinal NPPASensitivity (95% CI)Specificity (95% CI)PPV (95% CI)NPV (95% CI)
Clark et. al. 2018 Not reported 36 75%        
Base substitutions/Indels       82.7% (69.7-91.8) 97.5% (95.9-98.5) 72.9% (59.7-83.6) 98.6% (97.3-99.4)
Rearrangements       100% (15.8-100) 99.1% (94.3-100) 66.7% (9.4-99.2) 100% (96.5-100)
Amplifications       38.5% (13.9-68.4) 100% (98.5-100) 100% 47.8-100) 96.8% (93.6-98.6)
Zhou et. al, (2018) Not reported 42 82%        
Base substitutions       77.2% (66.4-85.9) 96.0% (94.6-97.1) 59.2% (49.1-68.8) 98.3% (97.3-99.0)
Insertion/deletions       7.1% 0.9-23.5) 98.2% (95.5-99.5) 33.3% (4.3-77.7) 89.4% (84.9-93)
Amplifications       23.7% (11.4-40.2) 99.8% (98.8-100) 90.0% (53.2-1000 94.1% (91.7-96)
Rearrangements or fusions       100.0% (39.8-100) 97.6% (93.9-99.3) 50.0% 15.7-84.3) 100% (97.7-100)
Chung et. al. (2017)
Short variants Not reported 14 89% 89.5% (66.9-98.7) 92.4% (84.0-97.3) 73.9% 51.6-89.8) 97.3% (90.2.99.8)
Amplifications Not reported 14 27% 27.3% (6.0-61) 100% (95.1-100) 100% 29.2-100) 90.1% (81.5-95.6)
Kim et. al. (2017)
PIK3CA and AKT1 Not reported 72 100% 100% (93.4-100) 100% 81.5-100) 100% (47.8-100) 96.8% (93.6-98.6)

 

PPA: positive percent agreement; PPV: positive predictive value; NPV: negative predictive value

 

Table 3. Relevance, Design and Limitations of Clinical Validity Studies of FoundationOne Liquid CDx
StudyPopulationInterventionComparatorOutcomesDuration of Follow-Up
Clark et. al. (2018) Patients with advanced cancer Earlier version of test used FoundationAct FoundationOne tissue biopsy Futher tumor type specific studies are warranted to understand the performance of genomic profiling of ctDNAin the contxt of each cancer type Follow-up duration not sufficient with respect to natural history of disease (true-positive, true-negative, false-positives, false-negatives cannot be determined)
Zhou et.al. Patients with locally advanced or metstatic solid tumors (multiple cancer types) Earlier version of test used FoundationAct FoundationOne tissue biopsy Majority of the cases in this study (73%) was NSCLC, further studies are needed to consider the impact of different molecular subtypes and cancer types on tumor metabolic activity that might affect the production of plasma ctDNA Follow-up duration not sufficient with respect to natural history of disease (true-positive, true-negative, false-positives, false-negatives cannot be determined)
Chung et. al. (2017) Women with estrogen receptor-positive breast cancer Earlier version of test used FoundationAct FoundationOne tissue biopsy Genomic alterations (GA) relevant to relapsed/metastatic breast cancer management were identified, including diverse ESR1 Gas. Genomic profiling of ctDNA demonstrated sensitive detection of mutations found in tissue. Detection of amplifications we associated with ctDNA fraction. Genomic profiling of ctDNA may provide possible alternative approach to tissue-based genomic testing for patients with estrogen-receptor-positive metastatic breast cancer Follow-up duration not sufficient with respect to natural history of disease (true-positive, true-negative, false-positives, false-negatives cannot be determined)
Kim et. al. (2017) Women with measurable, inoperable locally advanced or metastatic TNBC previously untreated with systemic therapy Earlier version of test used FoundationAct FoundationOne tissue biopsy These results highlight a potential role of ctDNA in identifying genetic markers associated with improved treatment outcomes Follow-up duration not sufficient with respect to natural history of disease (true-positive, true-negative, false-positives, false-negatives cannot be determined)

 

Table 4. Study Design and Limitations of Clinical Validity Studies of FoundationOne Liquid
StudySelectionBlindingDelivery of TestData Completeness
Clark et. al. (2018) Selection not random or consecutive (i.e. convenience) Not blinded to results of reference or other comparator tests Timing of delivery of index or reference test not described Inadequate description of indeterminate and missing samples
Zhou et. al. (2018) Selection not random or consecutive (i.e. convenience) Not blinded to results of reference or other comparator tests Timing of delivery of index or reference test not described Inadequate description of indeterminate and missing samples
Chung et. al. (2017) Selection not random or consecutive (i.e. convenience) Not blinded to results of reference or other comparator tests Timing of delivery of index or reference test not described Inadequate description of indeterminate and missing samples
Kim et. al. (2017) Selection not random or consecutive (i.e. convenience) Not blinded to results of reference or other comparator tests Timing of delivery of index or reference test not described Inadequate description of indeterminate and missing samples

 

In 2017, Vidal et. al. evaluated the clinical validity of the OncoBEAM CRC colorectal cancer assay in a retrospective-prospective study in two Spanish institutions from June 2009 to August 2016 which included 115 patients with histologically confirmed metastatic colorectal cancer (CRC) that were anti-EGFR treatment naive. Blood samples were collected in all patients before the administration of anti-EGFR treatment. OncoBEAM CRC assay was used to detect RAS mutations in plasma and RAS mutation detection in tissue samples were carried out according to standard of care procedures validated by each hospital. The median time from tumor tissue specimen collection to ctDNA collection was 47.5 days (range 0-1783 days). Of the 115 patients included in the study, 55 (47.8%) and 59 (51.3%) were shown to have RAS mutations in their tumor samples as detected by standard of care RAS tissue testing and as detected in ctDNA by OncoBEAM assay and standard techniques for tissue analysis was 93% (107/115 patients), kappa index 0.844 (95% CI 0.746-0.914). There were several limitations to this study to include the retrospective analysis, longitudinal blood extractions were only carried out in limited number of patients and given the low number of patients with specific clinic-pathological characteristics the inferences from associations with P-values marginally <0.05% should be cautiously interpreted. While this study was promising clinical validity data needs replicated.

 

Guardant360 CDx

Guardant360 CDx is a qualitative next generation sequencing-based in vitro diagnostic device that uses targeted high throughput hybridization-based capture technology for detection of single nucleotide variants (SNVs), insertions and deletions (indels) in 55 genes, copy number amplifications (CNAs) in 2 genes and fusions in 4 genes. Guradant360 CDx utilizes circulating cell-free DNA (cfDNA) from plasma of peripheral whole blood collected in Streck Cell-Free DNA Blood Collection Tubes (BCTs).

 

The test in intended to be used as a companion diagnostic to identify non-small cell lung cancer (NSCLC) patients who may benefit from treatment with targeted therapy in accordance with approved therapeutic product labeling:

 

BiomarkerTherapy
EGFR exon 19 deletions, L858R and T790M Tagrisson (Osimertinib)

 

Liquid biopsy (circulating tumor DNA [ctDNA]) for NSCLC is further addressed in medical policy 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer.

 

Genetic biomarkers are associated in multiple advanced solid tumors, however, the evidence is most developed for genetic biomarkers in non-small cell lung cancer (NSCLC) using circulating tumor DNA (ctDNA) in selecting targeted therapy. The majority of outcome studies for Guardant360 have been for non-small cell lung cancer (NSCLC) (30). Outcome studies for Guardant360 have also been completed in colorectal cancer (7), breast cancer (5) and gastroesophageal cancer (7), however, these studies are limited in size and design.

 

Liang et al (2016) performed a retrospective chart review of 100 patients with stage 4 or high-risk stage 3 breast cancer. Of the 100 patients included in this study, 29 had a tissue analysis done during the course of treatment. Only the specific genomic alterations tested in both the cell-free DNA (cfDNA) and tissue DNA were included in this analysis. Of the 29 patients with tissue analysis, 6 had no evidence of disease at the time of cfDNA analysis and were excluded from the comparative analysis of genomic alterations found between cfDNA and tissue DNA. A total of 55 single nucleotide variants (SNVs) and 4 copy number variants (CNVs) were evaluated for both cfDNA and tissue DNA from the 23 remaining patients. The degree of agreement between genomic alterations found in tumor DNA (tDNA) and cfDNA was determined by Cohen's Kappa. Clinical disease progression was compared to mutant allele frequency using a 2-sided Fisher's exact test. The presence of mutations and mutant allele frequency was correlated with PFS using a Cox proportional hazards model and a log-rank test. The most commonly found genomic alterations were mutations in TP53 and PIK3CA, and amplification of EGFR and ERBB2. PIK3CA mutation and ERBB2 amplification demonstrated robust agreement between tDNA and cfDNA (Cohen's kappa = 0.64 and 0.77, respectively). TP53 mutation and EGFR amplification demonstrated poor agreement between tDNA and cfDNA (Cohen's kappa = 0.18 and 0.33, respectively).  The directional changes of TP53 and PIK3CA mutant allele frequency were closely associated with response to therapy (p = 0.002). The investigators stated that the presence of TP53 mutation (p = 0.0004) and PIK3CA mutant allele frequency [p = 0.01, HR 1.074 (95 % CI: 1.018 to 1.134)] was excellent predictors of PFS. The authors concluded that identification of selected cancer-specific genomic alterations from cfDNA may be a non-invasive way to monitor disease progression, predict PFS, and offer targeted therapy.  They noted that this study was limited by its small sample size and the inherent nature of retrospective data collection of existing genomic information.

 

Kim et al (2017) reported on an interim analysis of an open-label prospective, clinical trial of ctDNA in patients with metastatic NSCLC, gastric cancer (GC), and other cancers. The investigators reported that somatic alterations were detected in 59 patients with GC (78%), and 25 patients (33%) had targetable alterations (ERBB2, n = 11;MET, n = 5; FGFR2, n = 3; PIK3CA, n = 6). In NSCLC, 62 patients (85%) had somatic alterations, and 34 (47%) had targetable alterations (EGFR, n = 29; ALK, n = 2; RET, n = 1; ERBB2, n = 2). A subgroup of subjects (10 with GC and 17 with NSCLC) who had tissue for confirmation of ctDNA findings were treated with targeted therapy. The investigators reported that response rate and disease control rate were 67% and 100%, respectively, in GC and 87% and 100%, respectively, in NSCLC. The authors noted that this is the first prospective study to examine the clinical utility of comprehensive ctDNA genomic testing to guide matched therapy selection. The authors stated that, because this study was not randomized, its primary limitation is the potential for selection bias to enroll patients more likely to benefit. In addition, the cohort is heterogeneous, including patients at varying lines of therapy and with various concomitant treatments, which limits conclusions in this interim analysis. Not all patients with targetable alterations could receive matched therapy because of the various requirements of the multiple parallel matched therapy substudy protocols, performance status, or loss to follow-up. The authors stated that the final analysis will help to address the modest sample size of this interim analysis as well as report on progression-free survival. The authors stated that future studies should examine ctDNA guided matched therapy outcomes in more racially diverse cohorts.

 

Willis, et al. (2019) sought to analytically validate microsatellite instability (MSI) testing using Guardant360 according to established guidelines and clinically validate it using 1,145 cfDNA samples for which tissue MSI status based on standard-of-care tissue testing was available. The landscape of cfDNA-based MSI across solid tumor types was investigated in a cohort of 28,459 clinical plasma samples. Clinical outcomes for 16 patients with cfDNA MSI-H gastric cancer treated with immunotherapy were evaluated. In evaluable patients, cfDNA testing accurately detected 87% (71/82) of tissue MSI-H and 99.5% of tissue microsatellite stable (863/867) for an overall accuracy of 98.4% (934/949) and a positive predictive value of 95% (71/75). Concordance of cfDNA MSI with tissue PCR and next-generation sequencing was significantly higher than IHC. Prevalence of cfDNA MSI for major cancer types was consistent with those reported for tissue. Finally, robust clinical activity of immunotherapy treatment was seen in patients with advanced gastric cancer positive for MSI by cfDNA, with 63% (10/16) of patients achieving complete or partial remission with sustained clinical benefit. Limitations included the small number of subjects for which clinical outcomes were evaluated.

 

In 2019, Maron et. al. evaluated the role of circulating tumor DNA (ctDNA) utilizing 73-gene plasma-based next generation sequencing (NGS) cell-free circulating tumor DNA (ctDNA-NGS) test in guiding clinical decision making of gastroesophageal adenocarcinoma. Gastroesophageal adenocarcinoma (GEA) has a poor prognosis and few therapeutic options. A large cohort was evaluated (n=2140 tests; 1630 patients) of ctDNA-NGS results (including 369 clinically-annotated pts). Patients were assessed for genomic alteration (GA) distribution and correlation with clinicopathologic characteristics and outcomes. Treatment history, tumor site, and disease burden dictated tumor-DNA shedding and consequent ctDNA-NGS maximum somatic variant allele frequency (maxVAF). Patients with locally advanced disease having detectable ctDNA post-operatively experienced inferior median disease-free survival (mDFS) (p=0.03). The genomic landscape was similar but not identical to tissue-NGS, reflecting temporospatial molecular heterogeneity, with some targetable GAs identified at higher frequency via ctDNA-NGS compared to previous primary tumor-NGS cohorts. Patients with known microsatellite instability-high (MSI-High) tumors were robustly detected with ctDNA-NGS. Predictive biomarker assessment was optimized by incorporating tissue-NGS and ctDNA-NGS assessment in a complementary manner. HER2-inhibition demonstrated a profound survival benefit in HER2 amplified patients by ctDNA-NGS and/or tissue-NGS (mOS 26.3 versus 7.4 months (p=0.002)), as did EGFR inhibition in EGFR amplified patients (mOS 21.1 versus 14.4 months (p=0.01)). This study had some limitations. The Global-cohort, albeit large, was relatively limited in clinical utility without the granular clinicopathologic characteristics to contextualize the GA distribution landscape. Another inherent limitation when comparing the 73-gene cfDNA-NGS versus 315-gene tissue-NGS panel is the expected discordance resulting from technical and biological differences between these different tests of distinct biological compartments. Technical limitations leading to discordance between tissue and plasma obviously included non-overlapping genes, but also some regions of overlapping genes not sequenced on the ctDNA-NGS panel. Another technical limitation is the recognized inability of ctDNA-NGS to discern large-scale deletions amongst the vast sea of wildtype cfDNA. Despite the relatively large size of the Clinically-annotated cohort, inherent to low-frequency GAs, was our inability to definitively evaluate the prognostic importance of individual GAs nor the predictive impact of targeting these infrequent events. The authors concluded clinical ctDNA-NGS testing holds promise for GEA – both in the detection of minimal residual disease in early stage disease and as a serial tumor marker. ctDNA-NGS used in conjunction with tissue-NGS may be an approach to best identify actionable GAs and resistance mechanisms in order to overcome intrapatient heterogeneity. However, prospective validation of these findings in future studies is necessary for integration into clinical care.

 

In 2019, Patel et. al. investigated the circulating tumor DNA (ctDNA) in pancreatic cancer using clinical laboratory improvement amendments (CLIA) licensed and College of American Pathologist (CAP) accredited clinical laboratory, Guardant Health, Inc. All tissue DNA analyses in this study were performed by a CLIA-licensed and CAP-accredited laboratory, Foundation Medicine, Inc., the assay interrogated 315 genes. ctDNA was analyzed in 112 patients with PDAC (54–73 genes) and tissue DNA in 66 patients (315 genes) (both clinical-grade next-generation sequencing). Number of alterations, %ctDNA, concordance between ctDNA and tissue DNA, and correlation of ctDNA results with survival were assessed. The most common genes altered in ctDNA were TP53 (46% of patients, N = 51) and KRAS (44%, N = 49). Median number of characterized ctDNA alterations per patient was 1 (range, 0–6), but patients with advanced PDAC had significantly higher numbers of ctDNA alterations than those with surgically resectable disease (median, 2 versus 0.5, P = 0.04). Overall, 75% (70/94) of advanced tumors had ≥ 1 ctDNA alteration. Concordance rate between ctDNA and tissue DNA alterations was 61% for TP53 and 52% for KRAS. Concordance for KRAS alterations between ctDNA and tissue DNA from metastatic sites was significantly higher than between ctDNA and primary tumor DNA (72% vs 39%, P = 0.01). Importantly, higher levels of total %ctDNA were an independent prognostic factor for worse survival (hazard ratio, 4.35; 95% confidence interval, 1.85–10.24 [multivariate, P = 0.001]). A patient with three ctDNA alterations affecting the MEK pathway (GNAS, KRAS, and NF1) attained a response to trametinib monotherapy ongoing at 6 months. This study has several limitations. First, the ctDNA gene panel expanded with time, increasing from 54 to 73 genes . Therefore, a limitation of the study pertains to the fact that the sequencing panels were different and so not all genes sequenced in tissue were sequenced in ctDNA. Nonetheless, our tissue and ctDNA panels allowed the comparison of most of the commonly altered genes in pancreatic cancer using clinical-grade assays frequently utilized in patients. The discrepancy in the frequency of CDKN2A/B loss between ctDNA and tissue (with lower frequency in ctDNA) probably results from the fact that its allelic loss was not captured in older panels of the ctDNA sequencing. Second, not all patients had both ctDNA and tissue DNA tests; therefore, future concordance analysis should be performed with larger numbers of patients. Moreover, further analysis with tissue DNA from both primary tissue and metastatic sites may help inform the issues related to intratumoral heterogeneity (though in many patients with pancreatic cancer, accessing biopsy sites can be challenging or dangerous). Third, analysis of the influence of systemic treatment on ctDNA alterations is not feasible in this study due to the lack of serial ctDNA testing per patient. Finally, additional studies are also needed to determine the impact of matching ctDNA alterations to therapy beyond the eight patients matched in the current investigation.

 

Colorectal cancer (CRC) is the second most common cause of cancer deaths worldwide: The mortality rate is the fourth highest among men and third highest among women. The early diagnosis and treatment of CRC is necessary for clinical progress that improves patient outcomes. Importantly, early CRC detection can significantly improve the cure rate. Traditional clinical diagnostic methods include serum tumor markers, colonoscopy, imaging, and tissue biopsy. Carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) are used as serum tumor markers, but these two markers alone do not fully satisfy clinical needs due to their lack of sensitivity and specificity. Tumor biopsies also have clinical shortcomings. Due to substantial trauma and poor patient compliance, it is difficult to obtain repeat biopsies to monitor disease progression. Therefore, circulating tumor DNA (ctDNA) has emerged as a promising diagnostic tool for CRC. Isolating and detecting ctDNA is a significant challenge. First, ctDNA accounts for only a small portion of the total cfDNA in peripheral blood (sometimes <0.01%), which makes it difficult to obtain. In 2020, Bi, et. al. provided a review describing the clinical applications and prospects of ctDNA in colorectal cancer (CRC) diagnosis, monitoring and prognosis. The authors concluded as a potential tool for clinical practice, ctDNA has a promising future. However, there are still several areas of the liquid biopsy technology that require development including the clinical examination method, a standardized detection process, and quantitative standards. Variables that affect the sample quality, including sample collection, transportation, and storage, should be controlled. In addition, it is still difficult to separate specific ctDNA fragments from cfDNA. Selecting the best detection panel is also an ongoing challenge. Although ctDNA fragments are currently enriched based on ctDNA/cfDNA fragment length, more research in this area is needed to perform this is the best practice. Currently, the utility of ctDNA is not limited to quantitative assessment, but also provides information related to mutations, copy number variation, and epigenetics. A large quantity of prospective studies with ctDNA are still needed to prove its clinical utility. There are some lingering questions about how to make clinical decisions when ctDNA indicates a possible recurrence, but imaging does not provide an obvious confirmation during a follow-up, and the patients with ctDNA-positive whether need intensive therapy. Needless to say, key benefits of ctDNA are that it provides better metrics for precision medicine and that it breaks away from the limitations of tumor tissue biopsies. Furthermore, ctDNA enables non-invasive treatment monitoring and can inform prognostic evaluations. Ongoing prospective clinical trials with ctDNA are focused on the diagnosis, surveillance, and prognosis of CRC. With the rapid development of science and technology, liquid biopsies will certainly play a key role in the diagnosis and treatment of CRC.

 

In 2020, Turner et. al. assessed the accuracy of circulating tumor DNA (ctDNA) testing in advanced breast cancer and the ability of ctDNA testing to select patients for mutation-directed therapy. This was an open-label, multicohort, phase 2a, platform trial of ctDNA testing in 18 UK hospitals. Participants were women (aged ≥18 years) with histologically confirmed advanced breast cancer and an Eastern Cooperative Oncology Group performance status 0–2. Patients had completed at least one previous line of treatment for advanced breast cancer or relapsed within 12 months of neoadjuvant or adjuvant chemotherapy. Patients were recruited into four parallel treatment cohorts matched to mutations identified in ctDNA: cohort A comprised patients with ESR1 mutations (treated with intramuscular extended-dose fulvestrant 500 mg); cohort B comprised patients with HER2 mutations (treated with oral neratinib 240 mg, and if oestrogen receptor-positive with intramuscular standard-dose fulvestrant); cohort C comprised patients with AKT1 mutations and oestrogen receptor-positive cancer (treated with oral capivasertib 400 mg plus intramuscular standard-dose fulvestrant); and cohort D comprised patients with AKT1 mutations and oestrogen receptor-negative cancer or PTEN mutation (treated with oral capivasertib 480 mg). Each cohort had a primary endpoint of confirmed objective response rate. For cohort A, 13 or more responses among 78 evaluable patients were required to infer activity and three or more among 16 were required for cohorts B, C, and D. Recruitment to all cohorts is complete and long-term follow-up is ongoing. This trial is registered with ClinicalTrials.gov, NCT03182634; the European Clinical Trials database, EudraCT2015-003735-36; and the ISRCTN registry, ISRCTN16945804. Between Dec 21, 2016, and April 26, 2019, 1051 patients registered for the study, with ctDNA results available for 1034 patients. Agreement between ctDNA digital PCR and targeted sequencing was 96–99% (n=800, kappa 0·89–0·93). Sensitivity of digital PCR ctDNA testing for mutations identified in tissue sequencing was 93% (95% CI 83–98) overall and 98% (87–100) with contemporaneous biopsies. In all cohorts, combined median follow-up was 14·4 months (IQR 7·0–23·7). Cohorts B and C met or exceeded the target number of responses, with five (25% [95% CI 9–49]) of 20 patients in cohort B and four (22% [6–48]) of 18 patients in cohort C having a response. Cohorts A and D did not reach the target number of responses, with six (8% [95% CI 3–17]) of 74 in cohort A and two (11% [1–33]) of 19 patients in cohort D having a response. The most common grade 3–4 adverse events were raised gamma-glutamyltransferase (13 [16%] of 80 patients; cohort A); diarrhea (four [25%] of 20; cohort B); fatigue (four [22%] of 18; cohort C); and rash (five [26%] of 19; cohort D). 17 serious adverse reactions occurred in 11 patients, and there was one treatment-related death caused by grade 4 dyspnea (in cohort C). The availability and accuracy of ctDNA testing shown in this study compares favorably with tissue-based mutation testing. Nearly all patients (99%) received a result from ctDNA testing, contrasting with previous tumor sequencing studies where results were typically received in only 70–90% of patients. In addition, previous tumor sequencing generally only included patients with disease that could be biopsied, which is not consistent for ctDNA testing. Results were achieved relatively quickly after blood draw compared with results from tissue-based testing. The accuracy of ctDNA testing was similar to that achieved with tissue sequencing. Discordance between ctDNA results was still observed for patients at low allele frequency mutations, suggesting further potential for assay development. ESR1 mutations had lower percent-negative agreement, probably reflecting the subclonality of acquired ESR1 mutations, with ctDNA detecting mutations present in metastatic sites other than the one biopsied. Nevertheless, the degree of sensitivity observed in this study suggests that, within the patient population of advanced disease patients recruited, ctDNA testing could replace tissue-based mutation analysis. However, we note that tissue biopsy will remain important for immunohistochemistry, and for copy number-based assessment. Digital PCR offered similar accuracy to sequencing, with substantial cost efficiency, although this comparison was limited to the specific mutations analyzed. The academic clinical laboratory doing the digital PCR assay achieved the trial target turnaround time of results within 14 days. A shorter turnaround time could easily be achieved if required in clinical practice, resulting in a cost-efficient method of ctDNA analysis. 533 (51·1%) of 1044 patients who underwent ctDNA testing had a potentially targetable mutation (PIK3CA, ESR1, HER2, AKT1, or PTEN), indicating a potential value for ctDNA testing. Study limitations, inclusion of heavily pretreated patients might reduce activity of the targeted drugs, especially in cohort A, and future ctDNA selection trials might benefit from more restrictive entry criteria. The study was designed to asesss the activity of therapies against specific genomic events, but it did not target PIK3Ca mutations and as a result relatively few of the patients registered to the trial had a response to therapy (17 [1-6%] of 1051 patients).

 

Current NCCN Guidelines:

  • Breast Cancer Version 6.2020: The clinical use of Circulating Tumor Cells (CTC) or Circulating DNA (ctDNA) in metastatic breast cancer is not yet including in NCCN Guidelines for Breast Cancer for disease assessment and monitoring. Patients with persistently increased CTC after 3 weeks of first-line chemotherapy have a poor PFS and OS. In spite of its prognostic ability, CTC count has failed to show a predictive value.  A prospective randomized phase 3 trial (SWOG S0500) evaluated the clinical utility of serial enumeration of CTC in patients with metastatic breast cancer. According to the study results, switching to an alternative cytotoxic therapy after 3 weeks of first-line chemotherapy in patients with persistently increased CTC did not affect either PFS or OS.
  • Colon Cancer Version 4.2020:  Several multigene assays have been developed in hopes of providing prognostic and predictive information to aid in decisions regarding adjuvant therapy in patients with Stage II or III colon cancer. In summary, the information from these tests can further inform risk of recurrence over the other risk factors, but the panel questions the value added. Furthermore, there is no evidence of predictive value in terms of the potential benefit of chemotherapy to any of the available multigene assays. The panel believes there are insufficient data to recommend the use of multigene assays to determine adjuvant therapy.
  • Esophageal and Esophagogastric Junction Cancers Version 4.2020: The genomic alterations of solid cancers may be identified by evaluating circulating tumor DNA (ctDNA) in the blood, hence a form of “liquid biopsy.” Liquid biopsy is being used more frequently in patients with advanced disease who are unable to have clinical biopsy for disease surveillance and management. The detection/alterations in DNA shed with esophageal and EGJ carcinomas can identify targetable alterations or the evolution of clones with altered treatment response profiles. In a study that analyzed the genomic alterations of 55 patients with advanced gastroesophageal adenocarcinomas using NGS performed on plasma-derived ctDNA 69% of patients had > 1 characterized alteration theoretically targetable by an FDA approved agent (on or off label). Therefore, testing using a validated NGS-based comprehensive genomic profiling assay performed in a CLIA-approved laboratory may be considered for some patients. A negative result should be interpreted with caution, as this does not exclude the presence of tumor mutations or amplifications. The liquid biopsy platform is in its early phase of development and more research would be necessary before it can be considered standard of care.
  • Gastric Cancer Version 3.2020: The genomic alterations of solid cancers may be identified by evaluating circulating tumor DNA (ctDNA) in the blood, hence a form of “liquid biopsy.” Liquid biopsy is being used more frequently in patients with advanced disease who are unable to have clinical biopsy for disease surveillance and management. The detection/alterations in DNA shed with gastric carcinomas can identify targetable alterations or the evolution of clones with altered treatment response profiles. In one study, a complete or partial response to immunotherapy was achieved by 63% of patients with advanced gastric carcinoma who tested positive for MSI by cell-free DNA analysis. In another study that analyzed the genomic alterations of 55 patients with advanced gastroesophageal adenocarcinomas using NGS performed on plasma-derived ctDNA 69% of patients had > 1 characterized alteration theoretically targetable by an FDA approved agent (on or off label). Therefore, testing using a validated NGS-based comprehensive genomic profiling assay performed in a CLIA-approved laboratory may be considered for some patients. A negative result should be interpreted with caution, as this does not exclude the presence of tumor mutations or amplifications. The liquid biopsy platform is in its early phase of development and more research would be necessary before it can be considered standard of care. 
  • Pancreatic Adenocarcinoma Version 1.2020:
    • New screening methods to identify patients with early pancreatic cancer than those with preinvasive lesions may prove to be beneficial in the future. Examples of techniques being investigated are microRNA biomarkers in whole blood and serum metabolism profiling. In addition, circulating cell-free DNA is being investigated as a possible biomarker for screening.
    • Algorithms for locally advanced, metastatic disease, disease progression and recurrence after resection have the following footnote: Tumor/somatic gene profiling is recommended for patients with locally advanced/metastatic disease who are candidates for anti-cancer therapy to identify uncommon mutations. Consider specifically testing for actionable somatic findings including, but not limited: fusions (ALK, NRG1, NTRK, ROS1) mutations (BRAF, BRCA 1/2, HER2, KRAS, PALB2), and mismatch repair (MMR) deficiency (detected tumor IHC, PCR or NGS). Testing on tumor tissue is preferred; however, cell-free DNA testing can be considered if tumor tissue testing is not feasible.  See Discussion section.

 

At this time the NCCN discussion section only includes information regarding cell-free DNA related to pancreatic cancer screening which states “is being investigated for a possible biomarker for screening” and does not include any additional information in the discussion section regarding the use of cell-free DNA testing for locally advanced disease, metastatic disease, disease progression or recurrence after resection to define what specific individuals this testing should be considered as an alternative to standard of care tissue biopsy. An update of the discussion section is currently in progress.

 

Biopsy

Although pathologic diagnosis is not required before surgery, it is necessary before administration of neoadjuvant therapy and for patients with locally advanced pancreatic cancer or metastatic disease. A pathologic diagnosis of adenocarcinoma of the pancreas is often made using fine-needle aspiration (FNA) biopsy with either EUS guidance (preferred) or CT. EUS-FNA is preferable to CT-guided FNA in patients with resectable disease because of better diagnostic yield, safety, and potentially low risk of peritoneal seeding with EUS-FNA when compared with percutaneous approach. Additional risks of CT-directed FNA biopsy include the potential for greater bleeding and infection because of the need to traverse vessels and bowel. EUS-FNA also gives the benefit of additional staging information at the time of biopsy.

 

EUS-FNA is highly accurate and reliable for determining malignancy. In rare cases when EUS-FNA cannot be obtained from a patient with borderline resectable or unresectable disease, other acceptable methods of biopsy exist. For instance, intraductal biopsies can be obtained via endoscopic cholangioscopy. A percutaneous approach or a laparoscopic biopsy are other alternatives, Pancreatic ductal brushings or biopsies can also be obtained at the time of ERCP, often revealing malignant cytology consistent with pancreatic adenocarcinoma.

 

Core needle biopsy is recommended if possible, for patients with borderline resectable disease to obtain adequate tissue for possible ancillary studies, such as genomic analysis or MSI testing.

 

At this time, the current NCCN guideline does not discuss or indicate when cell-free DNA testing should be performed as an alternative to standard of care tissue biopsy. An update of the discussion section is currently in progress.

 

Summary

Genetic biomarkers are associated in multiple advanced solid tumors, however, the Guardant360 evidence is most developed for genetic biomarkers in non-small cell lung cancer (NSCLC) using circulating tumor DNA (ctDNA) in selecting targeted therapy to predict response. The NCCN guideline for NSCLC recommends broad molecular profiling using clinically validated test(s) see medical policy 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer,

 

The current NCCN guidelines do not recommend the use of circulating tumor DNA (ctDNA) in breast cancer or colorectal cancer and while the guidelines may mention cell-free DNA as an option in pancreatic adenocarcinoma the current NCCN guideline does not discuss or indicate when cell-free DNA testing should be performed as an alternative to standard of care tissue biopsy. An update of the discussion section is currently in progress. In regards to esophageal and gastric cancers NCCN guidelines also mention the use of ctDNA, however, the guideline states “liquid biopsy platform is in its early phase of development and more research would be necessary before it can be considered standard of care.”

 

The detection of ctDNA is challenging because cell-free DNA is diluted by nonmalignant circulating DNA and usually represents a small fraction (<1%) of total cell-free DNA. Studies have demonstrated cell-free tumor DNA testing to generally have very high specificity, but significantly compromised sensitivity, with up to 30% false-negative rate. Standards for analytic performance characteristics of cell-free tumor DNA have not been established, and in contrast to tissue-based testing, no guidelines exist regarding the recommended performance characteristics of this type of testing. In addition, it is still difficult to separate specific ctDNA fragments from cfDNA. Selecting the best detection panel is also an ongoing challenge. Although ctDNA fragments are currently enriched based on ctDNA/cfDNA fragment length, more research in this area is needed to perform this is the best practice. A large quantity of prospective studies with ctDNA are still needed to prove its clinical utility. There are some lingering questions about how to make clinical decisions when ctDNA indicates a possible recurrence, but imaging does not provide an obvious confirmation during a follow-up, and the patients with ctDNA-positive whether they need intensive therapy. While studies may show promise in clinical validity for ctDNA using Gauardantt360 in advanced solid tumors other than NCSCL outcome study limitations in advanced solid tumors include small number of subjects and retrospective data collection. Also, since Guradant360 panel includes 55 genes an only a few are actionable based on current guidelines depending on the solid tumor, the clinical value of the entire panel in advanced solid tumors has not been established. The evidence is insufficient to determine the effects of the technology on net health outcomes.

 

Circulating Tumor Cells (CTCs)

In breast cancer, observations that estrogen receptor-positive tumors can harbor estrogen-receptor-negative circulating tumor cells (CTCs), that overt distant metastases and CTCs can have discordant human epidermal growth factor receptor 2 status compared with the primary tumor, and that the programmed death-ligand 1 is frequently expressed on CTCs in patients with hormone receptor-positive, HER2-negative breast cancer have suggested that trials investigating whether CTCs can be used to select targeted treatment are needed.

 

The clinical validity of each commercially available test must be established independently.

 

Prostate Cancer

Oncotype DX AR-V7 Nucleus Detect (Genomic Health, Inc.) is intended for use in patients with metastatic castration-resistant prostate cancer (mCRPC) who are considering androgen receptor signaling inhibitors (e.g. abiraterone, enzalutamide). This test identifies the presence of AR-V7 protein in the nucleus of circulating tumor cells (CTCs) in the blood to inform clinical decision-making. Not all mCRPC patients respond to androgen receptor (AR) targeted therapies, like abiraterone and enzalutamide. When AR-targeted therapy fails, acquired resistance could be the cause. The AR-V7 Nucleus Detect test identifies patients who will not benefit from AR-targeted therapies, is predictive of improved overall survival with taxanes versus AR-targeted therapies and provides easy to interpret results reported as either AR-V7+ (positive) or AR-V7- (negative). Patients eligible for this testing include those who have confirmed mCRPC, received and failed AR-targeted therapy (e.g. abiraterone, enzalutamide) and will guide subsequent therapeutic decision making.

 

In 2016 Schreiber et. al., a critical decision in the management metastatic castration-resistant prostate cancer (mCRPC) is when to administer an androgen receptor signaling (ARS) inhibitor or a taxane. Study was performed to determine if pretherapy nuclear androgen-receptor splice variant 7 (AR-V7) protein expression and localization on circulating tumor cells (CTCs) is a treatment-specific marker for response and outcomes between ARS inhibitors and taxanes. For this cross-sectional study at Memorial Sloan Kettering Cancer Center, 265 men with progressive mCRPC undergoing a change in treatment were considered; 86 were excluded because they were not initiating ARS or taxane therapy; and 18 were excluded for processing time constraints, leaving 161 patients for analysis. Between December 2012 and March 2015, blood was collected and processed from patients with progressive mCRPC immediately prior to new line of systemic therapy. Patients were followed up to 3 years. The main outcomes and measures included prostate specific antigen (PSA) response, time receiving therapy, radiographic progression-free survival (rPFS), and overall survival (OS). Overall, of 193 prospectively collected blood samples from 161 men with mCRPC, 191 were evaluable (128 pre-ARS inhibitor and 63 pretaxane). AR-V7–positive CTCs were found in 34 samples (18%), including 3% of first-line, 18% of second-line, and 31% of third- or greater line samples. Patients whose samples had AR-V7–positive CTCs before ARS inhibition had resistant posttherapy PSA changes (PTPC), shorter rPFS, shorter time on therapy, and shorter OS than those without AR-V7–positive CTCs. Overall, resistant PTPC were seen in 65 of 112 samples (58%) without detectable AR-V7–positive CTCs prior to ARS inhibition. There were statistically significant differences in OS but not in PTPC, time on therapy, or rPFS for patients with or without pretherapy AR-V7–positive CTCs treated with a taxane. A multivariable model adjusting for baseline factors associated with survival showed superior OS with taxanes relative to ARS inhibitors when AR-V7–positive CTCs were detected pretherapy (hazard ratio, 0.24; 95% CI, 0.10-0.57;P=.035).

 

In 2018, Scher et. al. performed a study to determine whether a validated assay for the nuclear-localized androgen receptor splice variant 7 (AR-V7) protein in circulating tumor cells can determine differential overall survival among patients with metastatic castration-resistant prostate cancer (mCRPC) treated with taxanes versus ARS inhibitors This blinded correlative study conducted from December 31, 2012, to September 1, 2016, included 142 patients with histologically confirmed mCRPC and who were treated at Memorial Sloan Kettering Cancer Center, The Royal Marsden, or the London Health Sciences Centre. Blood samples were obtained prior to administration of ARS inhibitors or taxanes as a second-line or greater systemic therapy for progressing mCRPC. The main outcomes and measures included overall survival (OS) after treatment with an ARS inhibitor or taxane in relation to pretherapy AR-V7 status. Among the 142 patients in the study (mean [SD] age, 69.5 [9.6] years), 70 were designated as high risk by conventional prognostic factors. In this high-risk group, patients positive for AR-V7 who were treated with taxanes had superior overall survival relative to those treated with ARS inhibitors (median overall survival, 14.3 vs 7.3 months; hazard ratio, 0.62; 95% CI, 0.28-1.39; P = .25). Patients negative for AR-V7 who were treated with ARS inhibitors had superior overall survival relative to those treated with taxanes (median overall survival, 19.8 vs 12.8 months; hazard ratio, 1.67; 95% CI, 1.00-2.81;P=.05). The authors concluded the validated nuclear-localized AR-V7 assay can be used to select a taxane or ARS inhibitor and provide individual patient benefit.

 

In 2018, Armstrong et. al. conducted and reported on the PROPHECY trial: multicenter prospective trial of circulating tumor cell (CTC) AR-V7 detection in men with metastatic castration-resistant prostate cancer (MCRPC) receiving abiraterone (A) or enzalutamide (E). The primary endpoint was association of baseline AR-V7 with radiographic/clinical progression free survival (PFS), using the Johns Hopkins modified-AdnaTest CTC AR-V7 mRNA assay and the Epic Sciences CTC nuclear AR-V7 protein assay. Overall survival (OS) and PSA decline were key secondary endpoints. Enrolled 118 men with mCRPC starting A/E; 52% had ≥5 Cellsearch CTCs, 36% had prior A/E. On study therapy was A (n = 56), E (n = 59) or both A/E (n = 3). AR-V7 detection by the JHU AR-V7 assay and the Epic AR-V7 assay were independently associated with worse PFS and OS after adjusting for CTC count and established clinical factors (see below table). Concordance between the two AR-V7 assays was 82%. Epic AR-V7 (+) men had more CTC phenotypic heterogeneity: 63% had Shannon Index > 1.5 vs 14% of AR-V7 (-) men; most CTCs in Epic AR-V7 (+) men were AR-V7 (-). We found genetic alterations of aggressive mCRPC in AR-V7 (+) and AR-V7 (-) men including gain of AR, MYCN, and MYC and loss of PTEN, TP53, and DNA repair enzymes in CTCs and ctDNA. The authors concluded they validated AR-V7 detection as an independent CTC-adjusted negative predictive biomarker of short PFS and OS with A/E treatment in men with mCRPC, identify CTC heterogeneity of AR-V7 expression, and highlight the importance of non-AR-V7 drivers of aggressive disease. Clinical Trial Information: NCT02269982.

 

OutcomeAR-V7 (JHU n = 116)
(+) n = 28 (24%) / (-) n = 88 (66%)
AR-V7 (Epic n = 105)
(+) n = 11 (10%) / (-) n = 94 (90%)
Median PFS (mo) 3.1 / 7.3 3.1 / 6.0
p-value 0.0003 0.007
HR* (95% CI) 2.4 (1.6-3.8) 2.4 (1.3-4.6)
HRo(95% CI) 2.4 (1.4-3.9) 2.2 (1.0-4.9)
Median OS (mo) 11.5 / 25.5 8.4 / 25.5
HR*(95% CI) 3.9 (2.1- 7.3) 4.5 (2.1-9.8)
HRo (95% CI) 4.6 (2.3-9.2) 3.6 (1.5-8.6)
≥ 50% confirmed PSA decline 11% / 28% 0% / 26%
Odds Ratio (95% CI) 0.31 (0.09-1.12) Not estimable

*univariate, oadjusted for Cellsearch CTC enumeration, PSA, Alk Phos, Hgb 

 

Clinically Useful

A test is clinically useful if the use of the results informs management decisions that improve the net health outcome of care. The net health outcome can be improved if patients receive correct therapy, or more effective therapy, or avoid unnecessary therapy or testing.

 

Circulating Tumor DNA (ctDNA)

Direct Evidence

Direct evidence of clinical utility is provided by studies that have compared health outcomes for patients managed with and without the test. The preferred evidence would be from randomized controlled trials (RCT).

 

Merker et. al. 2018 concluded that no such trials for clinical utility have been reported for circulating tumor DNA (ctDNA).

 

Chain of Evidence

To develop a chain of evidence or a decision model requires explication of the elements in the model elements in the model and evidence that is sufficient to demonstrate each of the links in the chain of evidence or the validity of the assumptions in the decision model.

 

A chain of evidence or a decision model requires details of the elements in the model and evidence that is sufficient to demonstrate each of the links in the chain of evidence or the validity of the assumptions in the decision model.

 

A chain of evidence of ctDNA tests could be established if the ctDNA test has a high agreement with standard tissue testing (clinical validity) for identifying drive mutations and the standard tissue testing has proven clinical utility with high levels of evidence. A chain of evidence can also be demonstrated if the ctDNA test is ale to detect drive mutations when standard methods cannot, and the information from the ctDNA test leads to management changes that improve outcomes.

 

The evidence is insufficient to demonstrate test performance for current available ctDNA tests except for lung cancer (see 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer (Liquid Biopsy); therefore, no inferences can be made about clinical utility.

 

Circulating Tumor Cells

Direct Evidence

Direct evidence of clinical utility is provided by studies that have compared health outcomes for patients managed with and without the test. Because these are intervention studies, the preferred evidence would be from RCTs.

 

Trials using CTCs to select treatment are ongoing.

 

Chain of Evidence

Indirect evidence on clinical utility rests on clinical validity. If the evidence is insufficient to demonstrate test performance, no inferences can be made about clinical utility.

 

The evidence is insufficient to demonstrate test performance for current available CTC tests; therefore, no inferences can be made about clinical utility.

 

The National Comprehensive Cancer Network (NCCN) current guideline for Prostate Cancer Version 2.2020 states “the panel recommends that use of AR-V7 tests can be considered to help guide selection of therapy in the post abiraterone/enzalutamide metastatic CRPC setting. (Category 2A: Based upon lower-level evidence there is uniform NCCN consensus that the intervention is appropriate).

 

Summary of Evidence

Circulating Tumor DNA (ctDNA)

Genetic biomarkers are associated in multiple advanced solid tumors, however, the evidence is most developed for genetic biomarkers in non-small cell lung cancer (NSCLC) using circulating tumor DNA (ctDNA) in selecting targeted therapy to predict response. The NCCN guideline for NSCLC recommends broad molecular profiling using clinically validated test(s) see medical policy 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer,

 

The detection of ctDNA is challenging because cell-free DNA is diluted by nonmalignant circulating DNA and usually represents a small fraction (<1%) of total cell-free DNA. Studies have demonstrated cell-free tumor DNA testing to generally have very high specificity, but significantly compromised sensitivity, with up to 30% false-negative rate. Standards for analytic performance characteristics of cell-free tumor DNA have not been established, and in contrast to tissue-based testing, no guidelines exist regarding the recommended performance characteristics of this type of testing. In addition, it is still difficult to separate specific ctDNA fragments from cfDNA. Selecting the best detection panel is also an ongoing challenge. Although ctDNA fragments are currently enriched based on ctDNA/cfDNA fragment length, more research in this area is needed to perform this is the best practice. A large quantity of prospective studies with ctDNA are still needed to prove its clinical utility. There are some lingering questions about how to make clinical decisions when ctDNA indicates a possible recurrence, but imaging does not provide an obvious confirmation during a follow-up, and the patients with ctDNA-positive whether they need intensive therapy. Also, the effectiveness of cell free DNA versus standard single lesion tumor biopsies has not been directly compared on large scale prospective cohorts of patients following progression on targeted therapy.

 

While studies may show promise in clinical validity for ctDNA using Gauardantt360 in advanced solid tumors other than NCSCL outcome study limitations in advanced solid tumors include small number of subjects and retrospective data collection. Also, since Guradant360 panel includes 55 genes and only a few are actionable based on current guidelines depending on the solid tumor, the clinical value of the entire panel in advanced solid tumors has not been established. The evidence is insufficient to determine the effects of the technology on net health outcomes.

 

The clinical validity of FoundationOne Liquid compared to tissue biopsy with FoundationOne comprehensive genetic testing was evaluated in four industry sponsored observational studies.  Published studies reporting clinical outcomes and/or clinical utility are lacking. The uncertainties concerning clinical validity and clinical utility preclude conclusions about whether variant analysis of ctDNA can replace variant analysis of tissue.The clinical value of the entire panel in advanced solid tumors has not been established The evidence is insufficient to determine the effects of the technology on net health outcomes.

 

In 2017, Vidal et. al. evaluated the clinical validity of OncoBEAM CRC in a retrospective-prospective study and while this study was promising clinical validity data needs replicated. The evidence is insufficient to determine the effects of the technology on net health outcomes.

 

The current NCCN guidelines do not recommend the use of circulating tumor DNA (ctDNA) in breast cancer or colorectal cancer and while the guidelines may mention cell-free DNA as an option in pancreatic adenocarcinoma the current NCCN guideline does not discuss or indicate when cell-free DNA testing should be performed as an alternative to standard of care tissue biopsy. An update of the discussion section is currently in progress. In regards to esophageal/esophagogastric junction and gastric cancers the NCCN guidelines mention the use of ctDNA, however, the guideline states “liquid biopsy platform is in its early phase of development and more research would be necessary before it can be considered standard of care.”

 

Circulating Tumor Cells

The use of circulating tumor cells (CTCs) has not been proven to impact meaningful health outcomes for most cancers. There is limited evidence to establish the clinical significance of circulating tumor cells (CTCs) and how identification can improve health outcomes. Studies suggest that the identification of circulating tumor cells (CTCs) may have a role in risk stratification and monitoring responses to treatment. National Comprehensive Cancer Network (NCCN) Prostate Cancer Version 2.2020 states “AR-V7 testing in circulating tumor cells (CTSs) can be considered to help guide selection of therapy in the post-abirterone/enzalutamide metastatic CRPC Setting.”  With the exception of testing for the AR-V7 variant in metastatic castrate-resistant prostate cancer (mCRPC) the role of this testing in patient management is not yet known. Larger longitudinal studies with standard techniques in clearly-defined populations of patients are needed to establish the role of this testing. The evidence is insufficient to determine the effects for the technology on net health outcomes except as indicated above for prostate cancer based on NCCN guideline recommendations. 

 

Monitoring Treatment Response in Cancer

Clinical Context and Test Purpose

Monitoring of treatment response in cancer may be performed by using tissue biopsy or imaging methods. Another proposed purpose of liquid biopsy testing in patients who have advanced cancer is to monitor treatment response, which could allow for changing therapy before clinical progression and potentially improve outcomes.

 

Patients

The relevant population of interest are patients being treated for cancer.

 

Interventions

The test being considered is liquid biopsy using either ctDNA or CTCs. For ctDNA tests, the best unit for quantifying DNA burden has not been established.

 

Comparators

Standard monitoring methods for assessing treatment response are tissue biopsy or imaging methods.

 

Outcome

The outcome of primary interest is progression-free survival.

 

The timing of interest for survival outcomes varies by type of cancer.

 

Clinically Valid

Circulating Tumor DNA (ctDNA)

Merker et. al (2018) identified several proof-of-principle studies demonstrating correlations between changes in ctDNA can identify the emergence of resistant variants.  However, they reported a lack of rigorous, prospective validation studies of ctDNA-based monitoring and concluded that clinical validity had not been established.

 

Circulating Tumor Cells (CTCs)

Systematic reviews and meta-analysis describing an association between circulating tumor cells (CTCs) and poor prognosis have been reported for metastatic breast cancer (MBC), colorectal cancer (CRC), hepatocellular cancer (HCC), prostate cancer, head and neck cancer and melanoma and are described below.

 

The clinical validity of each commercially available CTC test must be established independently.

 

Metastatic Breast Cancer

In 2015, Zhang et. al. conducted a systematic review and meta-analysis of published literature on the prognostic relevance of circulating tumor cells (CTCs), including patients with early and advanced breast cancer. Forty-nine eligible studies enrolling 6,825 patients were identified. The presence of CTC was significantly associated with shorter survival in the total population. The prognostic value of CTC was significant in both early (DFS: HR, 2.86; 95% CI, 2.19-3.75; OS: HR, 2.78; 95% CI, 2.22-3.48) and metastatic breast cancer (PFS: HR, 1.78; 95% CI, 1.52-2.09; OS: HR, 2.33; 95% CI, 2.09-2.60). Further subgroup analyses showed that our results were stable irrespective of the CTC detection method and time point of blood withdrawal. The authors concluded the present meta-analysis indicates that the detection of CTC is a stable prognosticator in patients with early stage and metastatic breast cancer. However, further studies are required to explore the clinical utility of CTC in breast cancer.

 

In 2016, LV et. al. conducted a systematic review and meta-analysis to clarify the correlation between circulating tumor cells (CTCs) and the clinicopathological features and prognosis of metastatic breast cancer (MBC). This meta-analysis included 24 studies (3701 MBC patients), 13 prospective studies and 11 retrospective studies. We found that CTCs were more frequently detected with HER2 positive primary tumors (pooled RR = 0.73, 95 % CI = 0.63-0.84). Additionally, higher CTC numbers indicated a worse treatment response (RR = 0.56, 95 % CI = 0.40-0.79), poorer PFS (RR = 0.64, 95 % CI = 0.56-0.73) and poorer OS (RR = 0.69, 95 % CI = 0.64-0.75) in MBC patients.

 

In 2017, Wang et. al. conducted a systematic review and meta-analysis to determine the prognostic value of HER2-positive circulating tumor cells (CTCs) in patients with breast cancer. Four studies with a total of 550 patients with stage I to IV breast cancer were included. HER2-positive CTCs were not associated with worse overall survival (OS [overall survival]; HR [hazard ratio], 1.489, 95% confidence interval [CI], 0.873-2.540, P = .144) or progression-free survival (PFS; HR, 1.543; 95% CI, 0.636-3.744; P = .338). In patients without metastasis, HER2-positive CTCs were associated with worse OS (HR, 2.273; 95% CI, 1.340-3.853; P = .002) and worse PFS (HR, 2.870; 95% CI, 1.298-6.343; P = .009). There was no significant relationship between HER2-positive CTCs and survival in subgroups of patients with metastasis.

 

Colorectal Cancer

Koerkamp et. al. (2013) performed a systematic review and meta-analysis to investigate the prognostic value of tumor cells in blood circulating tumor cells (CTCs) or bone marrow (BM) (disseminated tumor cells) of patients with resectable colorectal liver metastases or widespread metastatic colorectal cancer (CRC). The following databases were searched in May 2011: MEDLINE, EMBASE, Science Citation Index, BIOSIS, Cochrane Library. Studies that investigated the association between tumor cells in blood or BM and long-term outcome in patients with metastatic CRC were included. Hazard ratios (HRs) and confidence intervals (CIs) were extracted from the included studies and performed random-effects meta-analyses for survival outcomes. The literature search yielded 16 studies representing 1,491 patients. The results of 12 studies representing 1,329 patients were suitable for pooled analysis. The overall survival (HR, 2.47; 95 % CI 1.74-3.51) and progression-free survival (PFS) (HR, 2.07; 95 % CI 1.44-2.98) were worse in patients with CTCs. The subgroup of studies with more than 35 % CTC-positive patients was the only subgroup with a statistically significant worse PFS. All eight studies that performed multivariable analysis identified the detection of CTCs as an independent prognostic factor for survival.

 

In 2014, Huang et. al. conducted a meta-analysis to assess the prognostic and predictive value of circulating tumor cells (CTCs) in patients with colorectal cancer treated with chemotherapy. A comprehensive literature search for relevant studies was conducted in PubMed, Embase, the Cochrane Database, the Science Citation Index and the Ovid Database, up to April, 2014. Using the random-effects model in Stata software, version 12.0, the meta-analysis was performed using odds ratios (ORs), risk ratios (RRs), hazard ratios (HRs) and 95% confidence intervals (CIs) as effect measures. Subgroup and sensitivity analyses were also performed. Thirteen eligible studies were included. Our meta-analysis indicated that the disease control rate was significantly higher in CRC patients with CTC-low compared with CTC-high (RR = 1.354, 95% CI [1.002–1.830], p = 0.048). CRC patients in the CTC-high group were significantly associated with poor progression-free survival (PFS; HR = 2.500, 95% CI [1.746–3.580], p < 0.001) and poor overall survival (OS; HR = 2.856, 95% CI [1.959–4.164], p < 0.001). Patients who converted from CTC-low to CTC-high or who were persistently CTC-high had a worse disease progression (OR = 27.088, 95% CI [4.960–147.919], p < 0.001), PFS (HR = 2.095, 95% CI [1.105–3.969], p = 0.023) and OS (HR = 3.604, 95% CI [2.096–6.197], p < 0.001) than patients who converted from CTC-high to CTC-low. This meta-analysis included several limitations: it was not conclusive regarding when CTCs should be evaluated after the initiation of chemotherapy and what levels of CTCs would be useful for clinical prognostication; this was a retrospective study and was based on published data from the studies included; several studies did not provider hazard ratios (HRs) directly and were estimated from the published data; although the meta-regression showed that sampling time and detection method were the sources of heterogeneity, heterogeneity could not be eliminated because of patient characteristics, chemotherapy strategies, and heterogeneous CTC populations; and most of the studies included did not comprehensively report patient status regarding surgery or neoadjuvant chemotherapy and could not conduct an in-depth subgroup analysis that adjusted for these factors. The authors concluded that further high-quality, well-designed, large-scale multicenter studies are required to explore whether an individualized therapeutic decision based on CTC levels would improve the prognosis of CRC patients.

 

Hepatocellular Cancer (HCC)

In 2015, Fan et. al. conducted a meta-analysis of available studies to assess the prognostic value of circulating tumor cells (CTCs) in patients diagnosed with hepatocellular carcinoma (HCC). Medline, Ovid Database, Embase, The Science Citation Index, and Cochrane library, search was conducted on all studies reporting the outcomes of interest. The studies were set up according to the inclusion/exclusion criteria. Using a random-effects model, meta-analysis was performed using hazard ratio (HR), risk ratio (RR) and their 95% confidence intervals (95% CIs) as effect measures. Heterogeneity of the studies was tested for each pooled analysis. Subgroup and sensitivity analyses were also performed. Twenty-three published studies that matched the selection criteria were included in this meta-analysis. CTC positivity was significantly associated with relapse free survival (RFS) (HR 3.03, 95% CI: [1.89-4.86]; p<0.00001) and Overall survival (OS) (HR 2.45, 95% CI: [1.73-3.48]; p<0.00001). CTC positivity were also significantly associated with TNM Stage (RR 1.30, 95% CI: [1.02-1.65]; p=0.03), Tumor size (RR 1.36, 95% CI: [1.09-1.69]; p=0.006), Vascular invasion (RR 1.99, 95% CI: [1.43-2.77]; p<0.0001), Portal vein tumor thrombus (RR 1.73, 95% CI: [1.42-2.11]; p=0.0001), Serum alpha-fetoprotein (AFP) level (RR 2.05, 95% CI: [1.18-3.54]; p=0.01). The authors concluded that the results support the notion of a strong prognostic value of CTC in HCC. CTC could be useful as an effective indicator to evaluate the poor clinicopathological prognostic factors in the progression of HCC. However, further well-designed, large-scale detailed and accurate studies are required to explore CTC predictive value for the prognosis of patients with HCC.

 

Prostate Cancer

Wang et. al. (2011) performed a meta-analysis on the most recently reported circulating tumor cells (CTCs) to assess its prognostic effect and to determine whether its detection in the peripheral blood of patients diagnosed with metastatic, castration-resistant prostate cancer (CPRC) and hormone refractory prostate cancer (HRPC) can be used as a prognostic factor for survival. Science Direct, EMBASE, PubMed, and Cell Research databases were searched for studies that assessed the prognostic relevance of the presence number of circulating tumor cells (CTC) detection in the peripheral blood (PB). A fixed effects model with relative risk (RR) and 95% confidence interval (95% CI) was used for analysis. A total of 4 studies, including 486 patients, were eligible for final analysis. Pooled analysis indicated the presence number of CTC per 7.5 ml peripheral blood is associated with a poor survival rate (RR=2.51, 95% CI 1.96-3.21). The authors concluded, the results of this study suggest that presence of unfavorable numbers of CTCs is associated with a relatively shorter survival in patients with prostate cancer. However, this data does not establish CTC as a true surrogate of outcome, in order to establish that CTC can be used a surrogate for survival benefit it will require further evaluation in multiple prospective, randomized phase 3 therapeutic trials powered on survival end points on CTC as a biomarker, with meta-analytic analyses.

 

In 2014, Ma et. al. conducted a systematic review and meta-analysis for the prognostic role of circulating tumor cells (CTCs) and disseminated tumor cells (DTCs) in patients with prostate cancer. Relevant literature was searched in Pubmed and Embase. Survival data of included study were extracted. Forrest plots were used to estimate the effect of CTCs/DTCs on the survival of patients. Publication bias was evaluated using Begg's test. The estimated HRs and 95 % confidence interval for the effect of CTCs/DTCs on overall survival (OS) and biochemical relapse-free survival (bRFS) or disease-free survival (DFS) were 2.43 [2.07, 2.86] (p<0.00001) and 2.15 [1.69, 2.73] (p<0.00001), respectively. Subgroup analysis revealed that CTCs were also relevant to poor prognosis (hazard ratio (HR) 2.43 [2.05, 2.89] for OS, HR 2.46 [2.08, 2.90] for bRFS/DFS). A similar result was yielded in DTCs (1.47 [1.21, 1.80] for DFS). CTCs/DTCs could also predict poor OS in metastatic prostate cancer (2.37 [1.99, 2.82], p<0.00001) and in localized stage (HR 1.84 [1.47, 2.28], p<0.00001). In addition, CTCs/DTCs detected by different methods, especially by CellSearch system (HR for OS 2.36 [1.95, 2.85] and HR for bRFS/DFS 2.53 [1.66, 3.85]), were relevant to poor prognosis. Available evidence supported the notion of the strong prognostic value of CTCs.

 

Head and Neck Cancer

Sun et. al (2017) conducted a meta-analysis of clinicopathological and prognostic significance of circulating tumor cells (CTCs) in patients with head and neck cancer. PubMed, MEDLINE, EMBASE, Science Citation Index Expanded and Cochrane Library were searched up to February 2017. The estimated hazard ratio (HR), risk ratio (RR) and their 95% confidence intervals (95% CIs) were set as effect measures. All analyses were performed by STATA 12.0.A total of 17 studies were included in this meta-analysis. Positive CTCs were significantly associated with poor overall survival (HR =2.80, 95% CI: 1.34-5.86), disease-free survival (HR =3.86, 95% CI: 2.03-7.36) and progression-free survival (HR =3.31, 95% CI: 1.71-6.42). CTC-positive patients tend to have higher recurrence (RR =2.13, 95% CI: 1.26-3.59) and regional lymph node metastasis (RR =1.18, 95% CI: 1.02-1.36) rate and a more advanced tumor stage (RR =1.16, 95% CI: 1.03-1.32). Limitations of this meta-analysis included: the use of extracted data and not original data; limited studies were used for the prognostic value, and the heterogeneity was relatively obvious; the results may be influenced by accidental factor; and multiple CTC detection methods were involved. The authors concluded CTC detection has a great potential application in head and neck cancer. Positive CTCs in patients with head and neck cancer can predict the poor prognosis and the high recurrence and tumor progression rate. However, future large-scale multicenter studies are needed using the same standardized detection platforms to reduce inconsistencies across studies to further assess CTCs in patients with head and neck cancer.

 

Clinically Useful

Direct evidence of clinical utility is provided by studies that have compared health outcomes for patients managed with and without the test. The preferred evidence would be from randomized controlled trials (RCTs).

 

Circulating Tumor DNA (ctDNA)

Merker et. al (2018) the American Society of Clinical Oncology (ASCO) and College of American Pathologists jointly convened a panel to review the current evidence on the use of circulating tumor DNA (ctDNA) in patients with cancer. The literature search identified 1,338 references to which an additional 31 references were supplied by the expert panel. There were 77 articles selected for inclusion. They concluded that there is no evidence that changing treatment before clinical progression, at the time of ctDNA progression improves patient outcomes.

 

Circulating Tumor Cells

In 2014, Smerage et. al. reported on the results of a randomized controlled trial of patients with metastatic breast cancer (MBC) and persistently increased circulating tumor cell (CTC) levels to test whether changing chemotherapy after 1 cycle of first-line therapy could improve overall survival (OS) the primary study outcome. Patients with MBC who did not have increased CTCs at baseline remained on initial therapy until progression (arm A). Patients with initially increased CTCs that decreased after 21 days of therapy remained on initial therapy (arm B). Patients with persistently increased CTCs after 21 days of therapy were randomly assigned to continue initial therapy (arm C1) or change to an alternative chemotherapy (arm C2). Of 595 eligible and evaluable patients, 276 (46%) did not have increased CTCs (arm A). Of those with initially increased CTCs, 31 (10%) were not retested, 165 were assigned to arm B, and 123 were randomly assigned to arm C1 or C2. No difference in median OS was observed between arm C1 and C2 (10.7 and 12.5 months, respectively; P = .98). CTCs were strongly prognostic. Median OS for arms A, B, and C (C1 and C2 combined) were 35 months, 23 months, and 13 months, respectively (P < .001). The authors concluded this trial showed the prognostic significance of CTCs in patients with metastatic breast cancer receiving first-line chemotherapy. For patients with persistently increased CTCs after 21 days of first-line chemotherapy, early switching to an alternate chemotherapy was not effective in prolonging overall survival (OS). For this population, there is a need for more effective treatment than standard chemotherapy.

 

Trials demonstrating that use of CTCs to monitor treatment for the purpose of making treatment changes are needed to demonstrate clinical utility.

 

Indirect evidence on clinical utility rests on clinical validity. If the evidence is insufficient to demonstrate test performance, no conclusion can be made about clinical utility.

 

Summary of Evidence

For individuals who have cancer who receive testing of circulating tumor DNA (ctDNA) to monitor treatment response, the evidence includes observational studies. Given the different methodologies available to assess ctDNA, the clinical validity of each commercially available test must be established independently, and these data are lacking. Published studies reporting clinical outcomes and/or clinical utility are lacking. The uncertainties concerning clinical validity and clinical utility preclude conclusions about whether the use of ctDNA should be used to monitor treatment response. The evidence is insufficient to determine the effects of the technology on net health outcomes.

 

For individuals who have cancer who receive testing of circulating tumor cells (CTCs) to monitor treatment response, the evidence includes a randomized controlled trial, observational studies, and systematic reviews of observational studies. Given the different methodologies available to assess CTCs, the clinical validity of each commercially available test must be established independently, and these data are lacking. The available randomized controlled trial found no effect on overall survival when patients with persistently increased CTC levels after first-line chemotherapy were switched to an alternative cytotoxic therapy. Other studies reporting clinical outcomes and/or clinical utility are lacking. The uncertainties concerning clinical validity and clinical utility preclude conclusions about whether the use of CTCs should be used to monitor treatment response. The evidence is insufficient to determine the effects of the technology on net health outcomes.

 

Predicting Risk of Relapse/Recurrence

Clinical Context and Test Purpose

Monitoring for relapse after curative therapy in patients with cancer may be performed using imaging methods and clinical examination. Another proposed purpose of liquid biopsy testing in patients who have cancer is to detect and monitor for residual tumor, which could lead to early treatment that would eradicate residual disease and potentially improve outcomes.

 

Patients

The relevant population of interest are patients who have received curative treatment for cancer.

 

Interventions

The test being considered is liquid biopsy using either ctDNA or CTCs.

 

Comparators

Standard monitoring methods for detecting relapse are imaging methods and clinical examination.

 

Outcomes

The outcome of primary interest is progression-free survival.

 

The timing of interest for survival outcomes varies by type of cancer.

 

Clinically Valid

Circulating Tumor DNA (ctDNA)

Merker et. al (2018) identified several proof-of-principle studies demonstrating an association between persistent detection of ctDNA after local therapy and high-risk of relapse. However, current studies are retrospective and have not systematically confirmed that ctDNA is being detected before the metastatic disease has developed. They concluded that the performance characteristics had not been established for any assays.

 

The clinical validity of each commercially available CTC test must be established independently.

 

Signatera Assay

Is a circulating tumor DNA (ctDNA) for molecular residual disease (MRD) assessment and recurrence monitoring for patients previously diagnosed with cancer. Signatera assay can be used to detect recurrence earlier while it still may be resectable and reduce false positives.

 

Colon Cancer

2019 Reinert et. al., investigated the association of circulating tumor DNA (ctDNA) with recurrence using longitudinal data from ultradeep sequencing of plasma cell-free DNA in patients with colorectal cancer (CRC) before and after surgery, during and after adjuvant chemotherapy (ACT), and during surveillance. Outcomes were ctDNA measurement, clinical recurrence, and recurrence-free survival. A total of 130 patients with stages I to III CRC (mean [SD] age, 67.9 [10.1] years; 74 [56.9%] male) were enrolled in the study; 5 patients discontinued participation, leaving 125 patients for analysis. Preoperatively, ctDNA was detectable in 84 of 94 patients (89.4%). After definitive treatment, longitudinal ctDNA analysis identified 14 of 16 relapses (87.5%). At postoperative day 30, ctDNA-positive patients were 7 times more likely to relapse than ctDNA-negative patients (hazard ratio [HR], 7.2; 95% CI, 2.7-19.0; P < .001). Similarly, shortly after ACT ctDNA-positive patients were 17 times (HR, 17.5; 95% CI, 5.4-56.5; P < .001) more likely to relapse. All 7 patients who were ctDNA positive after ACT experienced relapse. Monitoring during and after ACT indicated that 3 of the 10 ctDNA-positive patients (30.0%) were cleared by ACT. During surveillance after definitive therapy, ctDNA-positive patients were more than 40 times more likely to experience disease recurrence than ctDNA-negative patients (HR, 43.5; 95% CI, 9.8-193.5 P < .001). In all multivariate analyses, ctDNA status was independently associated with relapse after adjusting for known clinicopathologic risk factors. Serial ctDNA analyses revealed disease recurrence up to 16.5 months ahead of standard-of-care radiologic imaging (mean, 8.7 months; range, 0.8-16.5 months). Actionable mutations were identified in 81.8% of the ctDNA-positive relapse samples.

 

Wang et. al. (2019) evaluated whether serial circulating tumor DNA (ctDNA) levels detected disease recurrence earlier, compared with conventional postoperative surveillance, in patients with resected colorectal cancer (CRC). This study included patients (n = 58) with stage I, II, or III CRC who underwent radical surgical resection at 4 Swedish hospitals from February 2, 2007, to May 8, 2013. Eighteen patients received adjuvant chemotherapy at the discretion of their clinicians, who were blinded to the ctDNA results. Blood samples were collected at 1 month after the surgical procedure and every 3 to 6 months thereafter for ctDNA analysis. Patients were followed up until metachronous metastases were detected, or for a median of 49 months. Data analysis was performed from March 1, 2009, to June 23, 2018. Sensitivity and timing of ctDNA positivity were compared with those of conventional surveillance modalities (computed tomographic scans and serum carcinoembryonic antigen tests) for the detection of disease recurrence. This study included 319 blood samples from 58 patients, with a median (range) age of 69 (47-83) years and 34 males (59%). The recurrence rate among patients with positive ctDNA levels was 77% (10 of 13 patients). Positive ctDNA preceded radiologic and clinical evidence of recurrence by a median of 3 months. Of the 45 patients with negative ctDNA throughout follow-up, none (0%; 95% CI, 0%-7.9%) experienced a relapse, with a median follow-up of 49 months. However, 3 (6%; 95% CI, 1.3%-17%) of the 48 patients without relapse had a positive ctDNA result, which subsequently fell to undetectable levels during follow-up. The authors concluded although these findings need to be validated in a larger, prospective trial, they suggest that ctDNA analysis could complement conventional surveillance strategies as a triage test to stratify patients with resected CRC on the basis of risk of disease recurrence.

 

Two cohort studies reported an association between positive ctDNA results using the Signatera assay and risk of recurrence of colon cancer. While these studies showed an association between ctDNA results and risk of recurrence, they are limited by their observational design and relatively small numbers of patients with positive results. Management decisions were not based on ctDNA test results. There are no controlled studies of management changes made in response to ctDNA test results compared to other risk factors, and no studies showing whether testing improved outcomes.

 

For individuals who have stage II or III colon cancer who receive circulating tumor DNA (ctDNA) testing, the evidence includes cohort studies. Relevant outcomes are disease-specific survival, test accuracy and validity, and change in disease status. Two cohort studies reported an association between positive ctDNA results and risk of recurrence of colon cancer. In one study, the recurrence rate among patients with positive ctDNA levels was 77% (10 of 13 patients); no patients with negative ctDNA experienced a relapse over a median followup of 49 months (range 11-70 months). In the other, the recurrence rate at 3 years was 70% in patients with a positive ctDNA test compared to 11.9% of those with a negative ctDNA test. While these studies showed an association between ctDNA results and risk of recurrence, they are limited by their observational design and relatively small numbers of patients with positive results. Management decisions were not based on ctDNA test results.There are no controlled studies of management changes made in response to ctDNA test results compared to other risk factors, and no studies showing whether testing improved outcomes. The evidence is insufficient to determine the effects of the technology on health outcomes.

 

Bladder Cancer

In 2019, Christensen et. al. addressed the prognostic and predictive impact of ultra-deep sequencing of cell-free DNA in patients before and after cystectomy and during chemotherapy. This study included 68 patients with localized advanced bladder cancer. Patient-specific somatic mutations, identified by whole-exome sequencing, were used to assess circulating tumor DNA (ctDNA) by ultra-deep sequencing (median, 105,000×) of plasma DNA. Plasma samples (n = 656) were procured at diagnosis, during chemotherapy, before cystectomy, and during surveillance. Expression profiling was performed for tumor subtype and immune signature analyses. Presence of ctDNA was highly prognostic at diagnosis before chemotherapy (hazard ratio, 29.1; P = .001). After cystectomy, ctDNA analysis correctly identified all patients with metastatic relapse during disease monitoring (100% sensitivity, 98% specificity). A median lead time over radiographic imaging of 96 days was observed. In addition, for high-risk patients (ctDNA positive before or during treatment), the dynamics of ctDNA during chemotherapy was associated with disease recurrence (P = .023), whereas pathologic downstaging was not. Analysis of tumor-centric biomarkers showed that mutational processes (signature 5) were associated with pathologic downstaging (P = .024); however, no significant correlation for tumor subtypes, DNA damage response mutations, and other biomarkers was observed. Our results suggest that ctDNA analysis is better associated with treatment efficacy compared with other available methods and a basis for clinical studies that evaluate early therapeutic interventions.

 

Esophageal Cancer

A case study by Einstein et. al. of oligometastatic recurrent esophageal adenocarcinoma (EAC) with longitudinal ctDNA assessment using a personalized, tumor-informed assay. Our study has certain limitations. As a single-patient longitudinal study, this alone cannot establish ctDNA as a disease-monitoring tool. Another aspect is how often and how long a patient should be monitored in this setting. Although tumor burden may be undetectable by the ctDNA assay, the patient is still at risk and needs surveillance. However, given the features described, it is reasonable to test this assay’s utility in multiple disease settings as part of clinical trials in esophageal and other cancers. In summary, this is the first case report to our knowledge that compares serial radiographic and serum CEA assessment of EAC with longitudinal ctDNA analysis.

 

Circulating Tumor Cells (CTCs)

In 2014, Rack et. al. published results of a large multicenter study in which circulating tumor cells (CTCs) were analyzed in 2026 patients with early breast cancer before adjuvant chemotherapy and in 1492 patients after chemotherapy using the CellSearch System. After immuno-magnetic enrichment for cells expressing the epithelial-cell adhesion molecule, CTCs were defined as nucleated cells expressing cytokeratin and lacking CD45. The patients were followed for a median of 35 months (range = 0-54). Kaplan-Meier analyses and the log-rank test were used for survival analyses. All statistical tests were two-sided. Before chemotherapy, CTCs were detected in 21.5% of patients (n = 435 of 2026), with 19.6% (n = 136 of 692) of node-negative and 22.4% (n = 299 of 1334) of node-positive patients showing CTCs (P < .001). No association was found with tumor size, grading, or hormone receptor status. After chemotherapy, 22.1% of patients (n = 330 of 1493) were CTC positive. The presence of CTCs was associated with poor disease-free survival (DFS; P < .0001), distant DFS (P < .001), breast cancer-specific survival (P = .008), and overall survival (OS; P = .0002). CTCs were confirmed as independent prognostic markers in multivariable analysis for DFS (hazard ratio [HR] = 2.11; 95% confidence interval [CI] = 1.49 to 2.99; P < .0001) and OS (HR = 2.18; 95% CI = 1.32 to 3.59; P = .002). The prognosis was worst in patients with at least five CTCs per 30 mL blood (DFS: HR = 4.51, 95% CI = 2.59 to 7.86; OS: HR = 3.60, 95% CI = 1.56 to 8.45). The presence of persisting CTCs after chemotherapy showed a negative influence on DFS (HR = 1.12; 95% CI = 1.02 to 1.25; P = .02) and on OS (HR = 1.16; 95% CI = 0.99 to 1.37; P = .06). Although the presence of persisting CTCs after chemotherapy was associated with worse outcomes, survival of patients without CTCs before chemotherapy was the same irrespective of CTC status after chemotherapy. Limitations of this study included: the short median follow-up of 35 months; the number of cells detected by the CellSearch system is relatively low and limited to cells with expression of Epcam and cytokeratin; and CTCs with decreased epithelial marker expression as a result of the epithelial-mesenchymal transition could be missed by the CellSearch Methodology. The authors concluded, that the data offers support for the clinical potential of CTCs to assess the individual risk of patients at the time of primary diagnosis and may be used for treatment tailoring in the absence of other strong quantitative markers.

 

Smaller studies demonstrating association between persistent circulating tumor cells (CTCs) and relapse have been published in prostate cancer, colorectal cancer (CRC), bladder cancer, liver cancer (hepatocellular cancer HCC), and esophageal cancer and are described below.

 

Prostate Cancer 

Thalgott et. al. (2015) reported on a study regarding circulating tumor cells (CTCs) possibly being prognostic for biochemical recurrence-free survival (bRFS) in patients with locally advanced high-risk prostate cancer (LAPC) undergoing neoadjuvant chemotherapy (NCHT) and radical prostatectomy (RP). CTCs were detected before and after NCHT, after RP and at follow-up using the CellSearch System for 59 blood samples (20 ml) from patients with LAPC (n=15) and, additionally, for 15 control samples. The median 5-year progression risk was 90%. CTCs (≥1/20 ml) were detected in 53.3% of patients, with a detection rate of 18.6% in sample-adjusted analysis. CTCs were detected at baseline in 20% of patients with LAPC and 6.7% of controls (p=0.6). CTC findings displayed no association with clinicopathological characteristics. The median bRFS of CTC-negative versus CTC-positive patients was 43.7 (95% confidence interval not reached) vs. 29.2 months (95% confidence interval=26.8-60.6 months), without statistical significance (p=0.76).

 

Colorectal Cancer

In 2013, Deneve et. al. reported on a study related to the capture of viable circulating tumor cells (CTCs) in the liver of colorectal cancer patients (CRC). The incidence and number of circulating tumor cells (CTCs) in the peripheral blood of colorectal cancer patients are lower than in other cancer types, which may point to a particular biology of colorectal cancer affecting CTC detection. They detected CTCs in the peripheral and mesenteric blood of colorectal cancer patients by use of 2 independent technologies on the basis of different biological properties of colon cancer cells. Seventy-five patients diagnosed with localized (M0, n = 60) and metastatic (M1, n = 15) colorectal cancer were included. Peripheral and mesenteric blood samples were collected before tumor resection. We performed CTC enumeration with an EpCAM-independent enrichment method followed by the Epispot assay that detected only viable CK19-releasing CTCs. In parallel, we used the FDA-cleared EpCAM-dependent CellSearch as the reference method. The enumeration of CK19-releasing cells by the CK19-Epispot assay revealed viable CTCs in 27 of 41 (65.9%) and 41 of 74 (55.4%) (P = 0.04) patients in mesenteric and peripheral blood, respectively, whereas CellSearch detected CTCs in 19 of 34 (55.9%) and 20 of 69 (29.0%) (P = 0.0046) patients. In mesenteric blood, medians of 4 (range 0-247) and 2.7 CTCs (range 0-286) were found with Epispot and CellSearch (P = 0.2), respectively, whereas in peripheral blood, Epispot and CellSearch detected a median of 1.2 (range 0-92) and 0 CTCs (range 0-147) (P = 0.002). A considerable portion of viable CTCs detectable by the Epispot assay are trapped in the liver as the first filter organ in CRC patients. The authors concluded, future investigations should focus on defining the best markers of the subpopulation of functional CTCs that are the metastasis initiating cells, defining the role of EpCAM in liver metastases formation, and identifying factors from colon CTCs able to induce the prometastatic microenvironment of the liver.

 

Bladder Cancer

Rink et. al. (2012) prospectively analyzed the prognostic role and HER2 expression of circulating tumor cells (CTCs) in peripheral blood of patients prior to radical cystectomy with clinically non-metastatic urothelial carcinoma of the bladder (UCB). Blood samples from 100 consecutive UCB patients treated with radical cystectomy (RC) were investigated for the presence (CellSearch system) of CTC and their HER2 expression status (immunohistochemistry). HER2 expression of the corresponding primary tumors and lymph node metastasis were analyzed using fluorescence in situ hybridization. Blood samples were taken preoperatively. Patients underwent RC with lymphadenectomy. Outcomes were assessed according to CTC status. HER2 expression of CTC was compared with that of the corresponding primary tumor and lymph node metastasis. CTC were detected in 23 of 100 patients (23%) with non-metastatic UCB (median: 1; range: 1-100). Presence, number, and HER2 status of CTC were not associated with clinicopathologic features. CTC-positive patients had significantly higher risks of disease recurrence and cancer-specific and overall mortality (p values: ≤ 0.001). After adjusting for effects of standard clinicopathologic features, CTC positivity remained an independent predictor for all end points (hazard ratios: 4.6, 5.2, and 3.5, respectively; p values ≤ 0.003). HER2 was strongly positive in CTC from 3 of 22 patients (14%). There was discordance between HER2 expression on CTC and HER2 gene amplification status of the primary tumors in 23% of cases but concordance between CTC, primary tumors, and lymph node metastases in all CTC-positive cases (100%). The study was limited by its sample size.

 

In 2014, Gazzaniga et. al. performed study to investigate whether the presence of circulating tumor cells (CTCs) may improve prognostication in a large population of patients with Stage I bladder cancer who were all candidates for conservative surgery. A prospective single center trial was designed to correlate the presence of CTC to local recurrence and progression of disease in high-risk T1G3 bladder cancer. One hundred two patients were found eligible, all candidate to transurethral resection of the tumor followed by endovesical adjuvant immunotherapy with BCG. Median follow-up was 24.3 months (minimum-maximum: 4-36). The FDA-approved CellSearch System was used to enumerate CTC. Kaplan-Meier methods, log-rank test and multivariable Cox proportional hazard analysis was applied to establish the association of circulating tumor cells with time to first recurrence (TFR) and progression-free survival. CTC were detected in 20% of patients and predicted both decreased TFR (log-rank p < 0.001; multivariable adjusted hazard ratio [HR] 2.92 [95% confidence interval: 1.38-6.18], p = 0.005), and time to progression (log-rank p < 0.001; HR 7.17 [1.89-27.21], p = 0.004).

 

Liver Cancer

Schulze et. al. (2013) investigated the prognostic relevance of EpCAM-positive circulating tumor cells (CTCs) in patients with HCC. Current imaging technologies do not sufficiently detect micrometastasis and therefore do not allow adequate stratification of patients with hepatocellular carcinoma (HCC) for curative or systemic therapy. Blood from 78 patients (19 patients in the control cohort and 59 patients with HCC) was tested for CTCs with the CellSearch system. Correlation analysis to overall survival (OS), the Barcelona Clinic Liver Cancer (BCLC) staging system, macroscopic and microscopic vascular invasion and alpha-fetoprotein (AFP) levels were performed. They detected ≥1 CTC in 18/59 HCC patients and in 1/19 patients with cirrhosis or benign hepatic tumor (p = 0.026). OS was significantly shorter (460 vs. 746 days) in the CTC-positive cohort (p = 0.017). Comparing BCLC stages, significant differences in CTC detection rates were also observed: BCLC stages A 1/9, B 6/31 and C 11/19 (p = 0.006). Ten of 18 patients with macroscopic and 10/16 patients with microscopic vascular invasion exhibited positive findings in CTC testing (p = 0.004 and p = 0.006). The authors concluded, CTC results correlated to AFP (cutoff > 400 ng/mL) levels (p = 0.050). The study demonstrates frequent presence of EpCAM-positive CTC in patients with intermediate or advanced HCC and its prognostic value for OS with possible implications for future treatment stratification.

 

Esophageal Cancer

In 2012, Vashist et. al. assessed the impact of disseminated tumor cells (DTC) in bone marrow on recurrence and survival in complete resected esophageal cancer (EC) in prospective study. Current modalities to predict tumor recurrence and survival in EC are insufficient. They enrolled 370 consecutive EC patients (1995-2009). All tumors, 189 squamous cell carcinomas and 181 adenocarcinomas, were completely surgically resected (R0), and patients received neither neoadjuvant nor adjuvant therapy. Disseminated tumor cells were detected by an immunocytochemical cytokeratin assay in preoperatively taken bone marrow aspirates. The results were correlated with clinic-pathological parameters and clinical outcome. Overall 120 (32.4%) patients harbored DTC in their bone marrow. Presence of DTC significantly correlated with aggressive tumor biology as indicated by increased tumor size (P = 0.026), regional (P = 0.002) and distant (P = 0.012) lymph node metastases, and higher relapse rate (P < 0.001, χ test). A gradual decrease in disease-free (P < 0.001) and overall (P < 0.001, log-rank test) survival was observed between DTC-negative and DTC-positive patients and was evident in subgroup analysis stratified for nodal status, lymph node yield, lymph node ratio, and tumor subtypes. Disseminated tumor cells were identified as a strong independent prognosticator of tumor recurrence (hazard ratio [HR] 4.0, 95% confidence interval [CI]: 2.96-5.45, P < 0.001) and overall survival (HR 3.1, 95% CI: 2.37-4.09, P < 0.001, Cox regression analysis).

 

Clinically Useful

Circulating Tumor DNA (ctDNA) and Circulating Tumor Cells (CTCs)
Direct Evidence

Direct evidence of clinical utility is provided by studies that have compared health outcomes for patients managed with and without the test. The preferred evidence would be from randomized controlled trials (RCTs).

 

Merker et. al. (2018) concluded that there is no evidence that early treatment before relapse, based on changes in circulating tumor DNA (ctDNA), improves patient outcomes.

 

No trials were identified demonstrating that treatment before relapse based on changes in circulating tumor cells (CTCs) improves patient outcomes.

 

Chain of Evidence

Indirect evidence on clinical utility rests on clinical validity.  If the evidence is insufficient to demonstrate test performance, no inferences can be made about clinical utility.

 

A chain of evidence to demonstrate clinical utility requires an evidence-based management pathway. There is not a clear evidence-based  management pathway for the use of ctDNA or CTCs to guide early treatment before relapse/recurrence.

 

Summary of Evidence

There is no direct evidence that using circulating tumor DNA (ctDNA) or circulating tumor cells (CTCs) to predict the risk of relapse/recurrence improves the net health outcome compared with standard methods. Given the different methodologies available to assess ctDNA and CTCs, the clinical validity of each commercially available test must be established independently, and these data are lacking. The evidence is insufficient to demonstrate test performance for currently available ctDNA and CTCs tests and therefore, no conclusion can be made about the clinical utility through a chain of evidence. Further high quality, well designed, large prospective studies are needed to explore and establish whether individualized therapeutic decisions based on ctDNA and CTC assays would improve net health outcomes. The evidence is insufficient to determine the effects of the technology on net health outcomes.

 

Screening for Cancer in Asymptomatic Individuals

Clinical Context and Test Purpose

It has been proposed that liquid biopsies could be used to screen asymptomatic patients for early detection of cancer, which could allow for initiating treatment at an early stage, potentially improving outcomes.

 

Patients

The relevant population of interest are asymptomatic individuals.

 

Interventions

The test being considered is liquid biopsy using either ctDNA or CTCs.

 

Comparators

Standard screening methods.

 

Outcomes

The outcome of primary interest is progression free survival.

 

The timing of interest for survival outcomes varies by type of care.

 

Diagnosis of cancer that is not present or would not have become clinically important (false-positives and over-diagnosis) would lead to unnecessary treatment and treatment related morbidity.

 

Clinically Valid

Circulating Tumor DNA (ctDNA)

Merker et. al. (2018) reported there is no evidence of clinical validity for the use of ctDNA in asymptomatic individuals.

 

Circulating Tumor Cells (CTCs)

Systematic reviews with meta-analyses have evaluated the diagnostic accuracy of CTCs in patients with gastric and bladder/urothelial cancer. Reported sensitivity was low in both cancers (42% and 35%) overall. Sensitivity was lower in patients with early-stage cancer, suggesting that the test would not be useful as an initial screen.

 

The clinical validity of each commercially available CTC test must be established independently.

 

Clinically Useful

A test is clinically useful if the use of the results informs management decisions that improve the net health outcomes of care. The net health outcome can be improved if patients receive correct therapy, or more effective therapy, or avoid unnecessary therapy, or avoid unnecessary testing.

 

Circulating Tumor DNA (ctDNA) and Circulating Tumor Cells (CTCs)
Direct Evidence

Direct evidence of clinical utility is provided by studies that have compared health outcomes for patients managed with and without the test. Because these are intervention studies, the preferred evidence would be from randomized controlled trials (RTCs).

 

To evaluate the utility of the tests for screening, guidelines would be needed to establish criteria for screening intervals and appropriate follow-up for positive tests. After such guidelines are established, studies demonstrating the liquid biopsy test performance as a cancer screening test would be needed.

 

Chain of Evidence

Indirect evidence on clinical utility rests on clinical validity. If the evidence is insufficient to demonstrate test performance, no inferences can be made about clinical utility. Also, a chain of evidence requires an evidence-based management pathway. There is not a clear, evidence-based management pathway for the use of ctDNA or CTCs for the screening of asymptomatic patients.

 

The evidence is insufficient to demonstrate test performance for currently available ctDNA and CTC tests as a screening test for cancer; therefore, no inferences can be made about clinical utility through a chain of evidence.

 

Summary of Evidence

For individuals who are asymptomatic and at high-risk for cancer who receive testing of ctDNA to screen for cancer, no evidence was identified. Relevant outcomes are overall survival (OS), disease-specific survival, test accuracy, and test validity. Published data on clinical validity and clinical utility are lacking. The evidence is insufficient to determine the effects of the technology on health outcomes.

 

For individuals who are asymptomatic and at high-risk for cancer who receive testing of CTCs to screen for cancer, the evidence includes observational studies. Relevant outcomes are overall survival (OS), disease-specific survival, test accuracy, and test validity. Given the breadth of methodologies available to assess CTCs, the clinical validity of each commercially available test must be established independently, and these data are lacking. Published studies reporting clinical outcomes and/or clinical utility are lacking. The evidence is insufficient to determine the effects of the technology on health outcomes.

 

 

Practice Guidelines and Position Statements

In 2018, the American Society of Clinical Oncology (ASCO) and College of American Pathologists issued a joint review on circulating tumor DNA in patients with cancer which states: Some ctDNA assays have demonstrated clinical validity and utility with certain types of advanced cancer; however, there is insufficient evidence of clinical validity and utility for the majority of ctDNA assays in advanced cancer. Evidence shows discordance between the results of ctDNA assays and genotyping tumor specimens and supports tumor tissue genotyping to confirm undetected results from ctDNA tests. There is no evidence of clinical utility and little evidence of clinical validity of ctDNA assays in early-stage cancer, treatment monitoring, or residual disease detection. There is no evidence of clinical validity and clinical utility to suggest that ctDNA assays are useful for cancer screening, outside of a clinical trial. Given the rapid pace of research, re-evaluation of this literature will shortly be required, along with the development of tools and guidance for clinical practice.

 

National Comprehensive Care Network (NCCN)

Anal Carcinoma Version 2.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in anal carcinoma is not included in this NCCN guideline.

 

Bladder Cancer Version 6.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in bladder cancer is not included in this NCCN guideline.

 

Breast Cancer Version 5.2020

Monitoring Metastatic Disease

The clinical use of circulating tumor cells (CTC) in metastatic breast cancer is not yet included in the NCCN guidelines for Breast Cancer for disease assessment and monitoring. Patients with persistently increased CTC after 3 weeks of first line chemotherapy have a poor PFS (progressive free survival) and OS (overall survival). In spite of its prognostic ability, CTC count has failed to show a predictive value. A prospective, randomized phase 3 trial (SWOG S0500) evaluated the clinical utility of serial enumeration of CTC in patients with metastatic breast cancer. According to the study results, switching to an alternative cytotoxic therapy after 3 weeks of first line chemotherapy in patients with persistently increased CTC did not affect either PFS (progressive free survival) or OS (overall survival).

 

Cervical Cancer Version 2.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in cervical cancer is not included in this NCCN guideline.

 

Colon Cancer Version 4.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in colon cancer is not included in this NCCN guideline.

 

Multigene Assays

Several multigene assays have been developed in hopes of providing prognostic and predictive information to aid in decisions regarding adjuvant therapy in patients with Stage II or III colon cancer.

 

In summary, the information from these tests can further inform risk of recurrence over the other risk factors, but the panel questions the value added. Furthermore, there is no evidence of predictive value in terms of the potential benefit of chemotherapy to any of the available multigene assays. The panel believes there are insufficient data to recommend the use of multigene assays to determine adjuvant therapy.

 

Rectal Cancer Version 6.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in rectal cancer is not included in this NCCN guideline.

 

Esophogeal and Esophagogastric Junction Cancers Version 2.2019
Principles of Pathologic Review and Biomarker Testing

Liquid Biopsy

The genomic alterations of solid cancers may be identified by evaluating circulating tumor DNA (ctDNA) in the blood, hence a form of “liquid biopsy.” Liquid biopsy is being used more frequently in patients with advanced disease who are unable to have clinical biopsy for disease surveillance and management. The detection/alterations in DNA shed with esophageal and EGJ carcinomas can identify targetable alterations or the evolution of clones with altered treatment response profiles. Therefore, for patients who are unable to undergo a traditional biopsy, testing using a validated NGS-based comprehensive genomic profiling assay performed in a CLIA-approve laboratory may be considered, A negative result should be interpreted with caution as this does not exclude the presence of tumor mutations or amplifications.

 

Discussion Section

Liquid Biopsy

The genomic alterations of solid cancers may be identified by evaluating circulating tumor DNA (ctDNA) in the blood, hence a form of “liquid biopsy.” Liquid biopsy is being used more frequently in patients with advanced disease who are unable to have clinical biopsy for disease surveillance and management. The detection/alterations in DNA shed with esophageal and EGJ carcinomas can identify targetable alterations or the evolution of clones with altered treatment response profiles. In a study that analyzed the genomic alterations of 55 patients with advanced gastroesophageal adenocarcinomas using NGS performed on plasma-derived ctDNA 69% of patients had > 1 characterized alteration theoretically targetable by an FDA approved agent (on or off label). Therefore, testing using a validated NGS-based comprehensive genomic profiling assay performed in a CLIA-approved laboratory may be considered for some patients. A negative result should be interpreted with caution, as this does not exclude the presence of tumor mutations or amplifications. The liquid biopsy platform is in its early phase of development and more research would be necessary before it can be considered standard of care. 

 

The current NCCN guideline does not indicate specific recommendations related to this testing as an alternative to standard of care tissue biopsy in which they infer “may be considered for some patients” and also states “more research would be necessary before it can be considered standard of care.”

 

Gastric Cancer Version 3.2020
Principles of Pathologic Review and Biomarker Testing

Liquid Biopsy

The genomic alterations of solid cancers may be identified by evaluating circulating tumor DNA (ctDNA) in the blood, hence a form of “liquid biopsy.” Liquid biopsy is being used more frequently in patients with advanced disease who are unable to have clinical biopsy for disease surveillance and management. The detection/alterations in DNA shed gastric carcinomas can identify targetable alterations or the evolution of clones with altered treatment response profiles. Therefore, for patients who are unable to undergo a traditional biopsy, testing using a validated NGS-based comprehensive genomic profiling assay performed in a CLIA-approve laboratory may be considered, A negative result should be interpreted with caution as this does not exclude the presence of tumor mutations or amplifications.

 

Discussion Section

Liquid Biopsy

The genomic alterations of solid cancers may be identified by evaluating circulating tumor DNA (ctDNA) in the blood, hence a form of “liquid biopsy.” Liquid biopsy is being used more frequently in patients with advanced disease who are unable to have clinical biopsy for disease surveillance and management. The detection/alterations in DNA shed with gastric carcinomas can identify targetable alterations or the evolution of clones with altered treatment response profiles. In one study, a complete or partial response to immunotherapy was achieved by 63% of patients with advanced gastric carcinoma who tested positive for MSI by cell-free DNA analysis. In another study that analyzed the genomic alterations of 55 patients with advanced gastroesophageal adenocarcinomas using NGS performed on plasma-derived ctDNA 69% of patients had > 1 characterized alteration theoretically targetable by an FDA approved agent (on or off label). Therefore, testing using a validated NGS-based comprehensive genomic profiling assay performed in a CLIA-approved laboratory may be considered for some patients. A negative result should be interpreted with caution, as this does not exclude the presence of tumor mutations or amplifications. The liquid biopsy platform is in its early phase of development and more research would be necessary before it can be considered standard of care. 

 

The current NCCN guideline does not indicate specific recommendations related to this testing as an alternative to standard of care tissue biopsy in which they infer “may be considered for some patients” and also states “more research would be necessary before it can be considered standard of care.”

 

Hepatobiliary Cancers Version 5.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in hepatobiliary cancers, particularly hepatocellular carcinoma (HCCH) is not included in this NCCN guideline.

 

Kidney Cancer Version 2.2021

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in kidney cancer is not included in this NCCN guideline.

 

Ovarian Cancer Including Fallopian Tube Cancer and Primary Peritoneal Cancer Version 1.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in ovarian cancer is not included in this NCCN guideline.

 

Pancreatic Adenocarcinoma Version 1.2020

In the locally advanced algorithm there is the following footnote: Tumor/somatic gene profiling is recommended for patients with locally advanced/metastatic disease who are candidates for anti-cancer therapy to identify uncommon mutations. Consider specifically testing for actionable somatic findings including, but not limited: fusions (ALK, NRG1, NTRK, ROS1) mutations (BRAF, BRCA 1/2, HER2, KRAS, PALB2), and mismatch repair (MMR) deficiency (detected tumor IHC, PCR or NGS). Testing on tumor tissue is preferred; however, cell-free DNA testing can be considered if tumor tissue testing is not feasible. See Discussion section.

 

In the metastatic disease algorithm there is the following footnote: Tumor/somatic gene profiling is recommended for patients with locally advanced/metastatic disease who are candidates for anti-cancer therapy to identify uncommon mutations. Consider specifically testing for actionable somatic findings including, but not limited: fusions (ALK, NRG1, NTRK, ROS1) mutations (BRAF, BRCA 1/2, HER2, KRAS, PALB2), and mismatch repair (MMR) deficiency (detected tumor IHC, PCR or NGS). Testing on tumor tissue is preferred; however, cell-free DNA testing can be considered if tumor tissue testing is not feasible. See Discussion section.

 

In the disease progression algorithm there is the following footnote: In the metastatic disease algorithm there is the following footnote: Tumor/somatic gene profiling is recommended for patients with locally advanced/metastatic disease who are candidates for anti-cancer therapy to identify uncommon mutations. Consider specifically testing for actionable somatic findings including, but not limited: fusions (ALK, NRG1, NTRK, ROS1) mutations (BRAF, BRCA 1/2, HER2, KRAS, PALB2), and mismatch repair (MMR) deficiency (detected tumor IHC, PCR or NGS). Testing on tumor tissue is preferred; however, cell-free DNA testing can be considered if tumor tissue testing is not feasible. See Discussion section.

 

In the recurrence after resection algorithm there is the following footnote: Tumor/somatic gene profiling is recommended for patients with locally advanced/metastatic disease who are candidates for anti-cancer therapy to identify uncommon mutations. Consider specifically testing for actionable somatic findings including, but not limited: fusions (ALK, NRG1, NTRK, ROS1) mutations (BRAF, BRCA 1/2, HER2, KRAS, PALB2), and mismatch repair (MMR) deficiency (detected tumor IHC, PCR or NGS). Testing on tumor tissue is preferred; however, cell-free DNA testing can be considered if tumor tissue testing is not feasible. See Discussion section.

 

Discussion Section

Pancreatic Cancer Screening

New screening methods to identify patients with early pancreatic cancer than those with preinvasive lesions may prove to be beneficial in the future. Examples of techniques being investigated are microRNA biomarkers in whole blood and serum metabolism profiling. In addition, circulating cell-free DNA is being investigated as a possible biomarker for screening. One study showed that methylation patterns in cell-free plasma DNA can differentiate between pancreatitis and pancreatic cancer with sensitivity of 91.2% and specificity of 90.8%.

 

At this time the NCCN discussion section only includes information regarding cell-free DNA related to pancreatic cancer screening which states “is being investigated for a possible biomarker for screening” and does not include any additional information in the discussion section regarding the use of cell-free DNA testing for locally advanced disease, metastatic disease, disease progression or recurrence after resection to define what specific individuals this testing should be considered as an alternative to standard of care tissue biopsy. An update of the discussion section is currently in progress.

 

Biopsy

Although pathologic diagnosis is not required before surgery, it is necessary before administration of neoadjuvant therapy and for patients with locally advanced pancreatic cancer or metastatic disease. A pathologic diagnosis of adenocarcinoma of the pancreas is often made using fine-needle aspiration (FNA) biopsy with either EUS guidance (preferred) or CT. EUS-FNA is preferable to CT-guided FNA in patients with resectable disease because of better diagnostic yield, safety, and potentially low risk of peritoneal seeding with EUS-FNA when compared with percutaneous approach. Additional risks of CT-directed FNA biopsy include the potential for greater bleeding and infection because of the need to traverse vessels and bowel. EUS-FNA also gives the benefit of additional staging information at the time of biopsy.

 

EUS-FNA is highly accurate and reliable for determining malignancy. In rare cases when EUS-FNA cannot be obtained from a patient with borderline resectable or unresectable disease, other acceptable methods of biopsy exist. For instance intraductal biopsies can be obtained via endoscopic cholangioscopy. A percutaneous approach or a laparoscopic biopsy are other alternatives, Pancreatic ductal brushings or biopsies can also be obtained at the time of ERCP, often revealing malignant cytology consistent with pancreatic adenocarcinoma.

 

Core needle biopsy is recommended if possible for patients with borderline resectable disease to obtain adequate tissue for possible ancillary studies, such as genomic analysis or MSI testing.

 

At this time the current NCCN guideline does not discuss or indicate when cell-free DNA testing should be performed as an alternative to standard of care tissue biopsy. An update of the discussion section is currently in progress.

 

Penile Cancer Version 2.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in penile cancer is not included in this NCCN guideline.

 

Prostate Cancer Version 2.2020

AR-V7 testing in circulating tumor cells (CTCs) can be considered to help guide selection of therapy in the post-abirterone/enzalutamide metastatic CRPC Setting (Discussed in more detail below under Progression After Enzalutamide or Abiraterone).

 

Progression after Enzalutamide and Abiraterone

Patients with disease progression after enzalutamide or abiraterone have the following options: docetaxel (category 1), abiraterone if previously given enzalutamide therapy, enzalutamide if previously given abiraterone, radium-223 for bone-predominate disease without visceral metastases (category 1), sipuleucel-T if asymptomatic or minimally symptomatic and without visceral metastases, life expectancy > 6 months, and ECOG score 0-1, pembrolizumab if MSI-H/dMMR (category 2B0, clinical trial, or secondary hormone therapy. All patients can continue through all treatment options and should receive best supportive care.

 

No randomized trials that compare taxane chemotherapies versus novel hormonal therapies in this setting have been reported, and some data suggest cross-resistance between abiraterone and enzalutamide. One molecular biomarker that may aid appropriate selection of therapy after progression on abiraterone or enzalutamide is the presence of androgen receptor splice variant 7 (AR-V7) in circulating tumor cells (CTCs). Lack of response of men with metastatic CRPC to abiraterone and enzalutamide was associated with detection of AR-V7 mRNA in CTCs using an RNA based polymerase chain reaction (PCR) assay. AR-V7 presence did not preclude clinical benefit from taxane chemotherapies (docetaxel and cabazitaxel). Men with AR-V7 positive CTCs exhibited superior progression-free survival with taxanes compared to novel hormonal therapies (abiraterone and enzalutamide); the two classes of agents resulted in comparable progression-free survival in men with AR-V7 negative CTCs. A confirmatory study used a different CTC assay that detected nuclear localized AR-V7 protein using immunofluorescence. Men with AR-V7 positive CTCs had superior OS with taxanes versus abiraterone or enzalutamide, whereas OS was not different between the two classes of agents among patients with AR-V7 negative CTCs. A blinded, correlative study at 3 cancer centers assessed the correlation between AR-V7 results before second-line treatment and OS in men with metastatic CRPC. Approximately half of the validation cohort received taxane therapy in first line, whereas half received an androgen receptor signaling inhibitor. In a high-risk subset of this cohort, patients negative for AR-V7 had superior OS if they were treated with an androgen receptor signaling inhibitor than if they were treated with taxane (median OS, 19.8 versus 12.8 months; HR, 1.67; 95% CI, 1.00-2.81; P = .05). Thus AR-V7 may be a useful predictive biomarker in men with metastatic CRPC after progression on abiraterone or enzalutamide.

 

These clinical experiences suggest that AR-V7 assays are promising predictors of abiraterone and enzalutamide resistance. Furthermore, the prevalence of AR-V7 positivity is only 3% in patients prior to treatment with enzalutamide, abiraterone and taxanes, so the panel believes AR-V7 detection would not be useful to inform treatment decisions in the naïve setting. On the other hand, the prevalence of AR-V7 positivity is higher after progression on abiraterone or enzalutamide (19%-39%), but data have already shown that abiraterone/enzalutamide crossover therapy is rarely effective and taxanes are more effective in this setting. The panel recommends that us of AR-V7 tests can be considered to help guide selection of therapy in the post abiraterone/enzalutamide metastatic CRPC setting.

 

Small Bowel Adenocarcinoma Version 2.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in small bowel adenocarcinoma is not included in this NCCN guideline.

 

Testicular Cancer Version 3.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in testicular cancer is not included in this NCCN guideline.

 

Thyroid Carcinoma Version 2.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in thyroid carcinoma is not included in this NCCN guideline.

 

Uterine Neoplasms Version 2.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in uterine neoplasms is not included in this NCCN guideline.

 

Vulvar Cancer Version 3.2020

The clinical use of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in vulvar cancer is not included in this NCCN guideline.

 

Regulatory Status

The CellSearch™ system (Janssen Diagnostics, formerly Veridex) is the only U.S. Food and Drug Administration (FDA) approved device for monitoring patients with metastatic disease and CTCs. In 2004, the CellSearch™ system was cleared by the FDA for marketing through the 510(k) process for monitoring metastatic breast cancer, in 2007 for monitoring metastatic colorectal cancer, and in 2008 for monitoring metastatic prostate cancer. The system uses automated instruments manufactured by Immunicon for sample preparation (Cell Tracks® AutoPrep) and analysis (CellSpotterAnalyzer®), together with supplies, reagents, and epithelial cell control kits manufactured by Veridex.

 

In August 2020, FoundationOne Liquid CDx (Foundation Medicine), a qualitative next generation sequencing-based diagnostic for circulating cell-free DNA in plasma,was approved by the FDA through the premarket approval process (P190032). The plasma test is approved as a companion diagnostic for selecting NSCLC patients who have EGFR exon 19 deletions and EGFR exon 21 L858R substitution variants, although information on multiple solid tumor biomarkers is also assessed. Genomic findings for biomarkers other than EGFR are not validated for choosing a particular corresponding treatment.. Prior versions of FoundationOne Liquid CDx were previously marketed as FoundationACT and FoundationOne laboratory developed test (LDT). Liquid biopsy for NSCLC is further addressed in medical policy 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer.

 

Tumor TypeBiomarker(s) DetectedTherapy
Non-small cell lung cancer (NSCLC) EGFR Exon 19 deletions and EGFR Exon 21 L858R substitution IRESSA® (gefitinib)
TAGRISSO® (osimertinib)
TARCEVA® (erlotinib)

 

In August 2020 Guardant360 CDx (Guardant Health) a qualitative next generation sequencing-based diagnostic of circulating cell-free DNA in plasma, was approved by the FDA through the premarket approval process (P200010). The plasma test is approved as a companion diagnostic for selecting NSCLC patients who have EGFR exon 19 deletions, L858R substitution variants, or T790M variants, for treatment with osimertinib (Tagrisso), although information on multiple solid tumor biomarkers is also assessed. Genomic findings for biomarkers other than EGFR are not validated for choosing a particular corresponding treatment.. Prior version of Guardant360 CDx was previously marketed as Guardant360. Liquid biopsy for NSCLC is further addressed in medical policy 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer.

 

Clinical laboratories may develop and validate tests in-house and market them as a laboratory service; laboratory developed tests (LDTs) must meet the general regulatory standards of the Clinical Laboratory Improvement Amendments (CLIA). Circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) (liquid biopsy) for cancer management is available under the auspices of Clinical Laboratory Improvement Amendments.  Laboratories that offer LDTs must be licensed by CLIA for high complexity testing. To date, the U.S. Food and Drug Administration (FDA) has chosen not to require any regulatory review of this test.

 

Prior Approval:

Not applicable

 

Policy:

See related medical policies

  • 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer (Liquid Biopsy)
  • 02.04.78 Molecular Analysis for Targeted Therapy of Non-Small Cell Lung Cancer
  • 02.04.77 Proteomic Testing for Targeted Therapy in Non-Small Cell Lung Cancer
  • 02.04.55 Epidermal Growth Factor Receptor (EGFR) Testing
  • 02.04.20 KRAS/NRAS and BRAF Mutational Analysis
  • 02.04.63 Expanded Genetic Panels to Identify Targeted Cancer Therapy

 

Oncotype DX AR-V7 testing from circulating tumor cells (CTCs) is considered medically necessary for individuals with metastatic castrate resistant prostate cancer (mCRPC) considering second line therapy when ALL of the following criteria are met:

  • Progression* on androgen receptor – signaling inhibitor (ARSi) therapy enzalutamide (Xtandi) or abiraterone (Zytiag); AND
  • AR-V7 will be assessed to guide subsequent therapeutic decision making.

 

*Progressive mCRPC is defined by the Prostate Cancer working Group 2 guidelines as the following: a minimum of 2 rising prostate-specific antigen (PSA) levels 1 or more weeks apart, new lesions by bone scintigraphy, and/or new or enlarging soft tissue lesions by computed tomography (CT) or magnetic resonance imaging (MRI). 

 

The detection and use of circulating tumor DNA (ctDNA) or circulating tumor cells (CTCs) (liquid biopsy) is considered investigational for all indications, including but not limited to the following commercially available tests:

  • Cancer Intercept
  • CellMax - First Sight CRC Colorectal Cancer Early Detection Test
  • CellMax – LBx Liquid Biopsy
  • CellMax – PanCa Monitoring Test
  • CellMax – Prostate Cancer Test
  • CellSearch
  • Circulogene
  • ClearID Biomarker Expression Assays
  • ClearID Breast Cancer
  • ClearID Lung Cancer
  • ClearID Solid Tumor Panel
  • Colvera
  • FoundationOne Liquid CDx (except for non-small cell lung cancer see medical policy 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer [Liquid Biopsy])
  • Guardant 360 CDx (except for non-small cell lung cancer see medical policy 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer [Liquid Biopsy])
  • IVDiagnostics
  • LiquidGx
  • OncoBEAM for Colorectal Cancer
  • OncoBEAM for Melanoma
  • Oncotype DX AR-V7 Nucleus Detect not meeting the above criteria
  • PlasmaSelect64
  • Signatera Bladder
  • Signatera Breast
  • Signatera Colon
  • Target Selector

 

Genetic biomarkers are associated in multiple advanced solid tumors, however, the evidence is most developed for genetic biomarkers in non-small cell lung cancer (NSCLC) using circulating tumor DNA (ctDNA) in selecting targeted therapy to predict response. The NCCN guideline for NSCLC recommends broad molecular profiling using clinically validated test(s) see medical policy 02.04.79 Circulating Tumor DNA for Management of Non-Small Cell Lung Cancer.

 

The use of circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) has not been proven to impact meaningful health outcomes for most advanced solid tumor cancers in selecting targeted therapy to predict response. It is still difficult to separate specific ctDNA fragments from cfDNA and selecting the best detection panel is also an ongoing challenge. Studies have demonstrated cell-free tumor DNA testing to generally have very high specificity, but significantly compromised sensitivity, with up to 30% false-negative rate. Standards for analytic performance characteristics of cell-free tumor DNA have not been established, and in contrast to tissue-based testing, no guidelines exist regarding the recommended performance characteristics of this type of testing.

 

The clinical validity of each commercially available test must be established independently. While studies may show promise in clinical validity for ctDNA in advanced solid tumors other than NCSCL to select targeted therapies to predict response a limitation in outcome studies in advanced solid tumors include small number of subjects and retrospective data collection. There are some lingering questions about how to make clinical decisions when ctDNA indicates a possible recurrence, but imaging does not provide an obvious confirmation during a follow-up, and the patients with ctDNA-positive whether they need intensive therapy. Also, the effectiveness of cell free DNA versus standard single lesion tumor biopsies has not been directly compared on large scale prospective cohorts of patients following progression on targeted therapy. A large quantity of prospective studies with ctDNA are still needed to prove its clinical utility.

 

The current NCCN guidelines do not recommend the use of circulating tumor DNA (ctDNA) in breast cancer or colorectal cancer and while the guidelines may mention cell-free DNA as an option in pancreatic adenocarcinoma the current NCCN guideline does not discuss or indicate when cell-free DNA testing should be performed as an alternative to standard of care tissue biopsy. An update of the discussion section is currently in progress. In regards to esophageal/esophagogastric junction and gastric cancers the NCCN guidelines mention the use of ctDNA, however, the guideline states “liquid biopsy platform is in its early phase of development and more research would be necessary before it can be considered standard of care.” See Practice Guideline and Position Statements above.

 

National Comprehensive Cancer Network (NCCN) Prostate Cancer Version 2.2020 states “AR-V7 testing in circulating tumor cells (CTSs) can be considered to help guide selection of therapy in the post-abirterone/enzalutamide metastatic CRPC Setting.”

 

There is limited evidence to establish the clinical significance of circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) and how identification can improve health outcomes. Some studies may suggest that the identification of circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) may have a role in selecting targeted therapies to predict response, risk stratification, monitoring responses to treatment and in predicting risk of relapse/recurrence, however, a limitation in outcome studies in advanced solid tumors includes small number of subjects and retrospective data collection. Selecting the best detection panel is also an ongoing challenge. While a few genetic biomarkers may be actionable based on current guidelines depending on the solid tumor, the clinical value of an entire panel in advanced solid tumors using circulating tumor DNA (ctDNA) or circulating tumor cells (CTCs) has not been established. The National Comprehensive Cancer Network (NCCN) Prostate Cancer Version 2.2020 states “AR-V7 testing in circulating tumor cells (CTCs) can be considered to help guide selection of therapy in the post-abirterone/enzalutamide metastatic CRPC Setting.” With the exception of testing for the AR-V7 variant in metastatic castrate-resistant prostate cancer (mCRPC) the role of this testing in patient management in all other advanced solid tumors remains insufficient. Further studies are needed to establish the role of this testing. The evidence is insufficient to determine the effects for the technology on net health outcomes.

 

Procedure Codes and Billing Guidelines:

To report provider services, use appropriate CPT* codes, Modifiers, Alpha Numeric (HCPCS level 2) codes, Revenue codes, and/or diagnosis codes.

  • 81445 Targeted genomic sequence analysis panel, solid organ neoplasm, DNA analysis, and RNA analysis when performed, 5-50 genes (eg, ALK, BRAF, CDKN2A, EGFR, ERBB2, KIT, KRAS, NRAS, MET, PDGFRA, PDGFRB, PGR, PIK3CA, PTEN, RET), interrogation for sequence variants and copy number variants or rearrangements, if performed
  • 81455 Targeted genomic sequence analysis panel, solid organ or hematolymphoid neoplasm, DNA analysis, and RNA analysis when performed, 51 or greater genes (eg, ALK, BRAF, CDKN2A, CEBPA, DNMT3A, EGFR, ERBB2, EZH2, FLT3, IDH1, IDH2, JAK2, KIT, KRAS, MLL, NPM1, NRAS, MET, NOTCH1, PDGFRA, PDGFRB, PGR, PIK3CA, PTEN, RET), interrogation for sequence variants and copy number variants or rearrangements, if performed
  • 81479 Unlisted molecular pathology procedure
  • 86152 Cell enumeration using immunologic selection and identification in fluid specimen (eg, circulating tumor cells in blood).
  • 86153 Cell enumeration using immunologic selection and identification in fluid specimen (eg, circulating tumor cells in blood); physician interpretation and report.
  • 0091U Oncology (colorectal) screening, cell enumeration of circulating tumor cells, utilizing whole blood, algorithm, for the presence of adenoma or cancer, reported as a positive or negative result (CellMax – First Sight CRC [Colorectal Cancer Early Detection Test])
  • 0239U Targeted genomic sequence analysis panel, solid organ neoplasm, cell-free DNA analysis of 311 or more genes, interrogation for sequence variants, including sequence variants, including substitutions, insertions, deletions, select rearrangements, and copy number variations (FoundationOne Liquid CDx)

 

 

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  • National Comprehensive Cancer Network (NCCN) Rectal Cancer Version 6.2020.
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  • National Comprehensive Cancer Network (NCCN) Hepatobiliary Cancers Version 5.2020.
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  • National Comprehensive Cancer Network  (NCCN) Gastric Cancer Version 3.2020.
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  • National Comprehensive Cancer Network (NCCN) Kidney Cancer Version 1.2021.
  • National Comprehensive Cancer Network (NCCN) Small Bowel Adenocarcinoma Version 2.2020.
  • National Comprehensive Cancer Network (NCCN) Testicular Cancer Version 3.2020.
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Policy History:

  • September 2020 - Annual Review, Policy Revised
  • September 2019 - Annual Review, Policy Revised
  • December 2018 - Interim Review, Policy Revised
  • September 2018 - Annual Review, Policy Revised
  • September 2017 - Annual Review, Policy Renewed
  • September 2016 - Annual Review, Policy Renewed
  • October 2015 - Annual Review, Policy Renewed
  • November 2014 - Annual Review, Policy Revised
  • January 2014 - Annual Review, Policy Renewed
  • January 2013 - Annual Review, Policy Renewed
  • January 2012 - Annual Review, Policy Renewed
  • January 2011 - Annual Review, Policy Renewed

Wellmark medical policies address the complex issue of technology assessment of new and emerging treatments, devices, drugs, etc.   They are developed to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. Wellmark medical policies contain only a partial, general description of plan or program benefits and do not constitute a contract. Wellmark does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Wellmark or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. Our medical policies may be updated and therefore are subject to change without notice.

 

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