Tuesday, April 19, 2022

AP story suggests liquid biopsies may be 'a new frontier in cancer screening for healthy people'

Liquid biopsies, or blood tests that look for cancer by checking for DNA fragments shed by tumor cells, are being billed "as a new frontier in cancer screening for healthy people."

A story in this week's San Francisco Chronicle by Associated Press medical writer Carla K. Johnson notes that these tests already are being "used in patients with cancer to tailor their treatment and check if tumors come back."

But one California-based company, Grail, is promoting the $949 test, the article says, "as a way to detect tumors in the pancreas, ovaries and other sites that have no recommended screening method."

Most insurance companies do not cover the cost, and the tests are being marketed "without endorsements from medical groups or a recommendation from U.S. health authorities," Johnson's piece says.

The Associated Press also observes that Federal Drug Administration "authorization, clearance or approval of such tests is required by law, but the agency historically has not enforced most regulatory requirements for ones – like Grail’s – that are designed, manufactured and used within a single laboratory."

The story quotes FDA spokesman Jim McKinney as reporting that the agency is working with Congress on legislation "to update the regulatory framework, which would include active oversight for such tests."

Although Grill intends to get FDA approval, it currently is marketing its test "as it submits data to the agency."

Meanwhile, Johnson's piece says, "U.S. government researchers are planning a large experiment — with 200,000 participants and possibly lasting seven years — to see if the blood tests can live up to the promise of catching more cancers earlier and saving lives."

Dr. Lori Minasian
"They sound wonderful, but we don't have enough information," the story quotes Dr. Lori Minasian of the National Cancer Institute's Division of Cancer Prevention, who is involved in planning the research. "We don't have definitive data that shows that they will reduce the risk of dying from cancer."

Whereas screening tests — mammography, PAP, colonoscopy, for example — look for one cancer at a time, claims Dr. Joshua Ofman, an executive at Grail, the new blood tests look for many cancers at once, a definite advantage.

More information on testing for disease can be found in "Rollercoaster: How a man can survive his partner's breast cancer," a VitalityPress book that I, Woody Weingarten, aimed at male caregivers.