FDA approves first blood test screening for colon cancer

WASHINGTON ( DC News Now ) — A new blood test may make it much easier and cheaper to screen for signs of colon cancer.

Test manufacturer Guardant said the Food and Drug Administration (FDA) approved its Shield test for screening in adults 45 years and older who have an average risk of colon cancer.

The test isn’t a replacement for colonoscopies but provides a noninvasive approach to screening.

Dr. John Marshall, the chief of hematology and oncology at MedStar Georgetown University Hospital, said anything that improves the screening process in general, “is a win.”

“This is a new way to test for if you have an early cancer or an early polyp in the colon that doesn’t involve your poop, that doesn’t involve a bowel prep,” Marshall said. “So for a lot of people, this means you’ve got no more excuse not to get screening for colon cancer.”

Doctors can already order Shield for patients as a laboratory test with an out-of-pocket price of $895. However, FDA approval is expected to increase coverage by private and government insurance.

The test looks for DNA fragments shed by tumor cells and precancerous growths. In a study published in March, the test caught 83% of the cancers but very few of the precancerous growths found by colonoscopy for colon cancer screening .

The test missed 17% of cancers, a performance that is on par with stool-based tests.

“Colonoscopy in the United States remains the gold standard. But let’s face it, we have younger people getting colon cancer,” Marshall said.

He said people who need to get a colonoscopy need to take a day off of work.

“There’s anesthesia, there’s the bowel prep and for many, that’s a barrier to having this testing,” Marshall added. “We do have very good stool testing and that’s a good test as well.”

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.

In the U.S., screening is recommended for healthy adults aged 45 to 75 because they are at average risk for colon cancer.

“A colonoscopy is done every so many years, maybe five, maybe 10 year interval for a colonoscopy. Don’t think that if your blood test is negative or your stool test is negative, that you’re also good for 5 to 10 years. That’s a test that has to be repeated much more often in order for it to be effective. So the big worry I have for this kind of announcement, in this kind of new technology is that people will go in negative blood tests, they think they’re done, they don’t need another one for 5 to 10 years. That’s not the way this works. Does work for colonoscopy, doesn’t work for these tests,” Marshall said.

Physicians will be able to run the Shield test after taking a simple blood draw, Guardant said in a statement. The company plans to launch its product “in the near future.”

The annual rate of U.S. colon cancer screening is nearly 60%, well short of the 80% of age-eligible adults goal set by the American Cancer Society and other groups.

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