Cancer 'supertests' screen for more than 50 cancers. But are they saving lives?

What if there was a screening test to check for cancers — more than 50 of them — with a single blood draw? There is, though an increasing number of voices say that despite its promise, the jury is still out on whether it's effective at prolonging life.

The Galleri test, marketed by the biotech company Grail, looks for evidence of tumors and cancer cells in the blood before they can be seen in conventional screenings. And while Galleri is not yet FDA-approved, it’s available by prescription for about $1,000.

Benjamin Mazer is a physician specializing in pathology and laboratory medicine who wrote an Atlantic piece called “Cancer Supertests are Here, But Are They Really Such a Good Idea?”

He joins host Robin Young to discuss the pros and cons of the so-called "cancer-finding supertests."

Editor's note: A previous version of this story mischaracterized how the Galleri test works. We regret the error.