Why Americans should heed doctor's advice on colonoscopies after study questions effectiveness

Newly released results from a highly-anticipated medical trial show some confusing results.

ByLeslie Brinkley KGO logo

Tuesday, October 11, 2022

Doctors weigh in on study questioning effectiveness of colonoscopies

Many other studies show getting a colonoscopy reduced the odds of dying of colon cancer by 70%. In this new study, it had a lower number.

SAN FRANCISCO (KGO) -- It's a dreaded right of passage for adults - getting a colonoscopy at age 45 and up. But new just released results from a highly-anticipated medical trial show some confusing results.

In the medical community, the colon cancer screening trial was supposed to be the gold standard following 80,000 people over 10 years, some who got a colonoscopy and some who didn't.

The results came out on Sunday.

"They found that colonoscopies did not reduce the odds of finding colon cancer as much as we thought," said ABC7 News Special Correspondent Dr. Alok Patel.

Many other studies had shown getting a colonoscopy reduced the odds of dying of colon cancer by 70%.

In this new study, it only reduced the odds by 20%.

"We're not ready to say, no, we won't do colonoscopies for colon cancer screening. There's just too much data out there to support the real benefit in colon cancer prevention from colonoscopies," Dr. Drew Schembre, medical director of G.I. Services at John Muir Health.

"We want to figure out where this study fits in among all the studies," he said

This latest trial only studied people in Norway, Sweden and Poland. Doctors say diet and lifestyles are different in the U.S. and could bring different results.

"We know that some people in the U.S. have a higher incidence of getting colon cancer, such as Black Americans. Also, a lot of people out there have a family history and higher risk of colon cancer. So this study in no way disregards colonoscopies," Dr. Patel said.

Colonoscopies started being recommended for people over 50 in the mid-1990s. Katie Couric famously televised her colonoscopy after her husband died of cancer at age 42.

"The rate of colon cancer in a younger population, people of age 40 and up, has been going up over the last 20 years which is why the recommendation was changed recently to people to start getting colonoscopies at age 45. It's extremely important for anyone out there with questions to talk with a health care professional, talk to a GI doctor and not just listen to these headlines," Dr. Patel said.