Colon cancer blood test offers new screening option

A blood test for colon cancer performed well in a study published Wednesday, offering a new kind of screening for a leading cause of cancer deaths.

The test looks for DNA fragments shed by tumor cells and precancerous growths. It’s already for sale in the U.S. for $895, but has not been approved by the Food and Drug Administration and most insurers do not cover it. The maker of the test, Guardant Health, anticipates an FDA decision this year.

In the study, the test caught 83% of the cancers but very few of the precancerous growths found by colonoscopy, the gold standard for colon cancer screening. Besides spotting tumors, colonoscopies can prevent the disease by removing precancerous growths called polyps.

But some people avoid the exam because of the hassle of getting time off work or the day-ahead preparation that involves drinking a strong laxative to empty the bowels.

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