CNN
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A new European study of colonoscopy — the largest of its kind — yielded mixed results, leaving some people wondering if they should be screened for colon cancer.
“I think the most important message is that colon cancer screening works and you should get screened,” Dr. Jason Dominitz told CNN. He is the National Director of Gastroenterology at the Veterans Health Administration, where he co-authored an editorial that accompanies the NEJM study.
During a colonoscopy, the doctor inserts a long, flexible tube into the rectum. A tiny camera at the end of the tube allows the doctor to see inside the colon. They look for precancerous polyps and cancerous growths, as well as any other abnormalities, and they can remove tissue that looks suspicious and take a biopsy.
Doctors do colonoscopies when someone has symptoms of colon cancer, and they screen people for colon cancer in people who don’t have symptoms. There are other ways to screen for colon cancer, such as checking for hidden blood in the stool, but if it looks suspicious on these tests, doctors usually recommend a colonoscopy.
“A colonoscopy is ultimately a test to evaluate colon cancer,” Dominitz said.
Dominitz helped CNN put together the results of this new study to see what it means for you. Spoiler alert: Colonoscopy saves lives!
What does this new study show about the effectiveness of colonoscopy?
In the study, about 12,000 people in Sweden, Poland and Norway underwent colonoscopy. They found a 31 percent lower risk of developing colon cancer and a 50 percent lower risk of dying from colon cancer, compared with those who were not invited for a colonoscopy.
Is this about anticipation?
Some studies in the United States suggest that colonoscopy is more effective. One study followed nearly 90,000 healthcare professionals for 22 years. Some of them opted for colonoscopy, while others did not. The researchers estimated that colonoscopy was associated with a 40% lower risk of colon cancer and a 68% lower risk of dying from colon cancer.
Why would the three European countries have different success rates compared to the US?
One reason, Dominitz said, may be that the majority of people in the European study had their colonoscopy without a sedative. In the European study, only 23 percent of patients received sedatives, but nearly everyone who had a colonoscopy in the United States received sedatives. Colonoscopy can be uncomfortable, and if people are in pain, doctors may even check less thoroughly without realizing it. Thoroughness — the folds and crevices that bring the scope into the colon — is important for finding growths called polyps. The more polyps doctors can find, the better they can reduce a patient’s risk of being diagnosed with or dying from colon cancer.
Bottom Line: Should You Still Get Screened for Colon Cancer?
Yes! In general, you should start having regular colonoscopies at age 45. It’s even younger for people at high risk because of family history or other factors; see these recommendations from the Centers for Disease Control and Prevention and the American Cancer Society. And screening doesn’t have to involve colonoscopy. There are other tests, but colonoscopy is the most common.
In the European study, people were invited to undergo colonoscopy. Why do you have to invite them? Isn’t colon cancer screening standard practice in those countries?
Only recently have Sweden, Poland and Norway started screening their populations for colon cancer. Their project began around 2015, and in the study, people were invited to have colonoscopies between 2009 and 2014. The patients were then followed for about 10 years to see if they developed colon cancer.
How many study participants agreed to an invitation to a colonoscopy?
In the European study, 28,000 people aged 55 to 64 were invited for colonoscopy. Only 42% said yes.
Why so few?
Part of the reason, Dominitz thinks, is that people in those countries aren’t used to the idea of a colonoscopy. They didn’t have it before, and their friends and family probably didn’t either. Also, during the study period, there was no campaign to encourage colonoscopy — no Katie Couric (or Ryan Reynolds) to raise awareness about colon cancer.