Liquid biopsy, a genetic test that can eliminate some of the most serious potential drawbacks of traditional tissue biopsy, is gaining more traction in cancer care. But there remain significant barriers to its widespread use.
Liquid biopsy, a genetic test that can eliminate some of the most serious potential drawbacks of traditional tissue biopsy, is gaining more traction in cancer care. But there remain significant barriers to its widespread use.
What Is a Liquid Biopsy?
An essential element of cancer care, tumor tissue biopsies can confirm a cancer diagnosis, identify the cell type of a tumor, and determine whether a patient’s tumor contains specific genetic alterations that may make them candidates for targeted therapies. However, tumor tissue biopsies require invasive procedures (including surgery), and some patients may not be candidates due to poor health or a tumor’s specific location in the body.
To overcome these barriers, researchers have developed technologies for capturing and analyzing DNA and other types of genetic material released by patients’ tumor cells into their blood. The removal of blood or other bodily fluids to detect cancerous cells or cancerous DNA is called liquid biopsy. Liquid biopsies have the benefit of being non-invasive, which means they can be done more frequently to better track tumors and mutations over time. They may also be used to validate the efficacy of a cancer treatment or monitor patients for potential relapse. And they can be a less costly alternative to the genomic analysis of tissue biopsies.
On June 1, 2016, the Food and Drug Administration approved the first liquid biopsy test for use in cancer. The test detects key mutations that make patients with advanced non-small cell lung cancer candidates for treatment with the targeted therapy erlotinib (Tarceva®). The FDA previously approved this test for this indication using tumor specimens; the new approval is for the detection of the same mutation using blood samples.
But barriers to using biomarker testing are common. Respondents to ACCC’s Trending Now in Cancer Care survey indicate that insufficient insurance coverage, reimbursement, and protocols are among the issues working against the widespread implementation of biomarker testing in oncology practices. Accordingly, the adoption of biomarker testing has been slow.
A study presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting found that of nearly 3,500 patients with advanced NSCLC, 90% had been given at least one biomarker test. However, only 46% of these patients had been given all five of the biomarker tests commonly used for NSCLC. There is also evidence of significant disparities in the use of biomarker testing among different racial groups. Another study presented at the same ASCO meeting revealed that 39% of Black patients with metastatic NSCLC underwent next-generation sequencing, compared to 50% of their White counterparts.
Cost & Coverage Barriers
The process of paying for expensive molecular tests and for the expertise of the multiple professionals required to interpret test results and formulate treatment plans is inconsistent and complex. This is especially the case with newer technologies such as liquid biopsy, which can come with higher price tags. Physicians, pathologists, and patients often do not know the costs of molecular testing services until they are reimbursed or billed. The confusion that results is distressing for both patients and providers.
Payers also structure their policies for biomarker coverage in multiple ways, making them difficult to understand. While some reimburse for many types of tests, others reimburse for only the most basic tests, or for tests for very specific clinical conditions and genes. This wide variation often increases the challenge of assessing and tracking numerous coverage policies.
To learn more about the status of liquid biopsies in community cancer centers, listen to the ACCC CANCER BUZZ podcast, What You Need to Know About Liquid Biopsy. There, J. Nicholas Bodor, MD, PhD, MPH—assistant professor in the Department of Hematology/Oncology at Fox Chase Cancer Center—and Kathryn A. Phillips, PhD—professor of health economics and health services research and director of the Center for Translational and Policy Research on Personalized Medicine at the University of California San Francisco—address the feasibility of offering liquid biopsies in community cancer centers and the pros and cons of doing so.
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