By Jocelyn KaiserDetecting many kinds of cancers early, with a simple blood test for DNA shed by tumor cells, is a seductive prospect.
Such tests, often called liquid biopsies, are now stepping out of the lab. This week a pioneering real-world study confirms some of their promise—and highlights a potential drawback that may soon confront physicians, regulators, and the public: a small but not insignificant number of alarming but false detections.In the first trial of such a test in a large, general population, instead of in groups with known tumors or at high risk of cancer, researchers screened nearly 10,000 women with CancerSEEK, an assay for circulating tumor DNA developed at Johns Hopkins University.