Why colonoscopies are less effective at finding cancer and saving lives

Turning 50 has never been anyone’s favorite birthday — for more reasons than one.

You can’t argue at this point in your life that you’re just “middle-aged” anymore…

You start getting mail offers from AARP to join up…

And your doctor starts bugging you about getting a colonoscopy.

Of course, the age of the dreaded procedure has dropped as the rates of colorectal cancer in younger people started to climb. Now the experts advise regular screening should start at age 45.

But if your time has come, or maybe come and gone because you’ve put it off, you may be looking for some guidance before you jump up on that table and allow a camera on a flexible tube to pass up your rectum.

You’re not alone, especially after the controversial results of a major study appear to indicate the screening procedure fails to lower colorectal cancer risks or prevent cancer deaths.

A worthless screening tool?

The results of the Northern-European Initiative on Colorectal Cancer trial (NordICC), an “intention-to-screen analysis,” were recently published in the New England Journal of Medicine.

It involved 84,585 healthy men and women (ages 55 to 64) drawn from population registries in Poland, Norway, Sweden, and the Netherlands between 2009 and 2014. The participants were randomly assigned in a 1:2 ratio to either receive an invitation to undergo a single screening colonoscopy (the invited group) or to receive no invitation or screening (the group was called the usual-care group). 

The participants were followed for 10 years while researchers measured two primary outcomes: the risks of colorectal cancer and related death, as well as death from any cause.

And the findings were not what they expected…

Offering the screening procedure did not significantly reduce cancer deaths over 10 years.

In fact, cancer cases were only reduced by 18 percent in the group invited to have a colonoscopy, compared to the group that wasn’t invited to get a screening.

According to Jason A. Dominitz, MD, of the University of Washington School of Medicine in Seattle, and Douglas J. Robertson, MD, of the Geisel School of Medicine at Dartmouth in Hanover, New Hampshire, who wrote an editorial that accompanied the research, “The relatively small reduction in the risk of colorectal cancer and the nonsignificant reduction in the risk of death are both surprising and disappointing.”

Bear in mind that the American Cancer Society estimates the number of new colorectal cases for 2022 at 151,030.

Why the less-than-stellar results?

The colonoscopy procedure remains largely unchanged from when it was first created and used in 1969 when it was hailed as a life-saving resource that could one day make colorectal cancer extinct.

So why the disappointing findings from the large NordICC trial?

A “screening can only be effective if it is performed,” the writers of the editorial point out.

See, in the group that was invited to undergo colonoscopy screenings, less than half of the participants (42 percent) actually went through with the procedure.

Per an adjusted analysis, the researchers found that if every participant had a colonoscopy the incidence of colorectal cancer would have been reduced by 31 percent and the risk of related cancer death by 50 percent.

But even though a 31 percent reduction in the adjusted analysis was “a clinically relevant benefit,” it was still lower than what is anticipated in clinical guidelines based on observational and modeling studies.

Previous research has put reduced incidence and death from colon cancer as high as 70 percent.

The difference between those studies and the NordICC? It may be a “real-world” statement on how useful colonoscopy actually is.

Based on the modest results from the NordICC study, the researchers wonder if it might be hard to justify the risk and expense of this form of screening when simpler, less invasive strategies are available.

However, with increased levels of participation in screening and with high-quality examinations, higher reductions in the incidence of colorectal cancer and related death would be expected — even if the percentages may not be as high in reality as previously thought. 

If you’d like to know more about those risks and less invasive strategies, download our free report — Before you say ‘yes’ to a colonoscopy!


Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death — The New England Journal of Medicine

If You Invite 455 People to Colonoscopy, You’ll Stop One Case of Cancer — MedPage Today

Key statistics for colorectal cancer — American Cancer Society

The colonoscopy: A historical timeline — Gastroenterology Health Partners

Margaret Cantwell

By Margaret Cantwell

Margaret Cantwell began her paleo diet in 2010 in an effort to lose weight. Since then, the diet has been instrumental in helping her overcome a number of other health problems. Thanks to the benefits she has enjoyed from her paleo diet and lifestyle, she dedicates her time as Editor of Easy Health Digest™, researching and writing about a broad range of health and wellness topics, including diet, exercise, nutrition and supplementation, so that readers can also be empowered to experience their best health possible.