At Technology Review, Antonio Regalado argues that shelling out money for a blood-based cancer-screening test like that from Pathway Genomics might not do any good yet.
Pathway says its $699 test can detect mutations linked to cancer within blood samples obtained from customers, thus catching any disease early. This, the Verge's Arielle Duhaime-Ross says, would be a big deal for medicine. But she and Regalado note there isn't much data showing that the test can do that.
Pathway CEO Jim Plante, though, tells the Verge that the CancerIntercept test has been validated using "hundreds of samples."
"The sensitivity of the test is very high and it can be used to potentially catch cancers at a much earlier stage," he adds.
Still, Pathway's chief medical officer tells Duhaime-Ross that these validation tests were run on people with known, well-defined cancers, not people not yet diagnosed with any disease. Glenn Braunstein, the CMO, adds that the company is pursuing longitudinal studies to determine whether positive findings lead to cancer diagnoses.
"Even if it's premature, what's important about Pathway's test is that it's a clear sign of things to come," Regalado says. Liquid biopsies do have the potential to find tumors early, but he adds they need to be fully vetted to deal with false positives, mutations that accumulate in people as they age, and how to interpret these mutations clinically.