Douglas Corley, MD, discusses study that questions colonoscopy benefits

Douglas Corley, MD, PhD

A recent New England Journal of Medicine study raised questions about the effectiveness of colonoscopies to prevent colon cancer deaths, and experts quoted in an NPR story said there is more to consider than what was covered in the large European study.

One of those experts quoted was Douglas Corley, MD, gastroenterologist with The Permanente Medical Group  and a physician-researcher at the Kaiser Permanente Division of Research in Northern California. Dr. Corley noted in the NPR article that the study looked at colonoscopies done from 2009 to 2014, but the methods in performing colonoscopies and the physicians’ skills have improved since then.

“The detection rate for polyps is much higher than it was 10 to 15 years ago,” Dr. Corley said. “The physician’s skill at detecting and removing polyps is better,” so if the study was done today “the benefit that we would expect to find now would be higher.”

Related story: “Erasing outcome disparities for colon cancer screening”

The NEJM study found that the participants only saw an 18% reduction in colorectal cancer among the men and women invited to get a colonoscopy. However, the NPR story noted that more than half of people invited to get a colonoscopy failed to show up.

The story also cited a 2018 Kaiser Permanente study that found a 67% reduction in cancer deaths among people who got a screening colonoscopy. It mentioned that Kaiser Permanente provides other screenings along with colonoscopies, including less invasive stool-based home testing or fecal immunochemical test known as FIT, which is mailed to members’ homes.

Dr. Corley noted that the European study only focused on colonoscopies and didn’t test the effectiveness of other screenings such as the home tests and sigmoidoscopies. He said that while each screening has its “pluses and minuses,” he encouraged people at risk for colon cancer because of things such as family history to follow up with their doctor or get screened.

Note: Read the full story on the NPR site.

Related story: “Permanente physicians lead expansion of at-home colorectal cancer screening”