Biopsies are a necessary burden for people with cancer. Taking a small sample of tissue and sending it through genetic and molecular analysis can help doctors not just diagnose cancer, but also learn more about its inner workings to find the best treatments based on which mutations are feeding the disease.
But tissue biopsies are invasive, and depending on where the tumors are in the body, they can be painful to obtain. For some people, there may not even be enough cancer tissue for doctors to get the answers they need.
In a press briefing previewing the upcoming American Association for Cancer Research annual meeting in Atlanta, researchers reported that a commercial blood test, called a liquid biopsy, was at least as effective as a tissue sample at identifying important mutations in non-small cell lung cancers, Time reports.
In a study funded by the manufacturer of the test, Guardant Health, 282 people at 28 centers in the U.S. with late-stage non-small cell lung cancer were tested both with Guardant’s liquid biopsy, called Guardant360, and their doctor’s choice of a tissue-based test to look for seven genetic markers in the tumors. Cancer experts have designated mutations in these markers as useful in guiding doctors to the appropriate therapies for attacking the cancer; a number of so-called targeted therapies designed to find and dismantle these mutations have been approved by the Food and Drug Administration (FDA) in recent years. Guardant 360 also looks for one genetic marker that can help to predict prognosis of these lung cancers.
The liquid biopsy was able to pick up these mutations at about the same rate as the tissue biopsies, which are currently the gold standard for testing. But the blood test also did so less invasively and took about half as long to produce results.
“This study shows that liquid biopsy is accurate and detects [markers] at the same rate as standard-of-care tissue testing of tumor tissue,” says Dr. Vassiliki Papadimitrakopoulou, professor of medicine at MD Anderson Cancer Center and lead author of the study. “This study gives us confidence that what is found in liquid biopsies really is what is found in the tumor.” (Papadimitrakopoulou serves on a number of advisory boards for pharmaceutical companies and received nominal fees as a consultant to Guardant in designing and running this trial.)