The ability to detect cancer from a blood sample may not be far off
Judging from developments in 2019, liquid biopsy is set take off in clinical diagnostics, though it’s unlikely to find a place in the physician office anytime soon.
The National Cancer Institutes defines liquid biopsy as a test done on a sample of blood to look for cancer cells from a tumor that are circulating in the blood or for pieces of DNA from tumor cells that are in the blood. It may also be used to help plan treatment or to find out how well treatment is working, or if cancer has returned.
Here are a few blood-biopsy developments in 2019.
Lung cancer
Biodesix, Inc., a Boulder, Colorado-based lung cancer diagnostic company, announced in July it had entered into an agreement with Thermo Fisher Scientific to bring a blood-based next-generation sequencing (NGS) assay to market with premarket approval classification from the U.S. Food and Drug Administration. The program will focus on an NGS-based solution for patients with advanced non-small-cell lung cancer. The assay is said to enable reproducible detection and analysis of tumor DNA and RNA across all major classes of somatic mutations from a single vial of blood within two days.
Early cancer detection
GRAIL (Menlo Park, California) announced data from the Circulating Cell-free Genome Atlas (CCGA) study that it says demonstrates the ability of its investigational multi-cancer blood test to detect a strong signal for 12 cancer types at early stages with a specificity of at least 99 percent (or a false positive rate of one percent or less). In addition, the test identified where the cancer originated in the body (the tissue of origin) with high accuracy.
Detection rates (sensitivity) for the 12 deadly cancer types ranged from 59 to 86 percent at early stages (stages I-III). A combined analysis of this group of cancers showed robust detection at early stages (34 percent, 77 percent, and 84 percent at stages I, II, and III, respectively). In addition, a tissue-of-origin result was provided for 94 percent of all cancers detected and, of these, the test correctly identified the tissue of origin in 90 percent of cases.
The 12 pre-specified cancer types were anorectal, colorectal, esophageal, gastric, head and neck, hormone receptor negative breast, liver, lung, ovarian, and pancreatic cancers, as well as multiple myeloma and lymphoid neoplasms. Together, these cancer types account for approximately 63 percent of all cancer deaths in the United States, according to the company.
Blood biopsy beats tissue testing
In February, Guardant Health (Redwood City, California) announced positive results from a lung-evaluation study that compared the Guardant 360® assay to tissue testing for the identification of guideline-recommended biomarkers in first-line advanced non-small-cell lung cancer patients. The company reported that investigators found that the assay identified guideline-recommended biomarkers in 77 patients, while tissue testing identified them in 60. For each patient in whom Guardant360 identified a target of an FDA-approved drug, tissue also detected the same alteration. Additionally, Guardant360 results were reported in an average of nine days, versus 15 days for tissue.
Alzheimer’s detection
Blood biopsy may also yield information about non-cancer conditions. A report at the Alzheimer’s Association International Conference in Los Angeles in July described methods for measuring abnormal versions of amyloid protein – the building block of one of the hallmark brain lesions of Alzheimer’s disease – in blood, and correlating it with established Alzheimer’s markers. Two additional reports described new blood-based methods for assessing alpha synuclein, which contributes to the brain changes of Parkinson’s disease and Dementia with Lewy Bodies; and neurofilament light, which may turn out to be the most reliable indicator of general brain cell damage.
Currently, the brain changes that occur before Alzheimer’s dementia symptoms appear can only be reliably assessed by positron-emission tomography (PET) scans, and from measuring amyloid and tau proteins in spinal fluid, according to the association. These methods are expensive and, in the case of a spinal tap, invasive. And, too often, they are unavailable, not covered by insurance or difficult to access.