CNN –
A new European study of colonoscopies, the largest of its kind, has complicated results and left some people wondering whether they should have the procedure to screen for colon cancer.
“I think the biggest message is that colon cancer screening is effective, and you should get screened,” Dr. Jason Dominitz told CNN. He is the national director of gastroenterology for the Veterans Health Administration and co-authored an editorial accompanying the study in The New England Journal of Medicine.
In a colonoscopy, a doctor inserts a long, flexible tube into the rectum. A small video 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 may cut out tissue that looks suspicious and biopsie it.
Doctors do colonoscopies when someone has symptoms of colon cancer, and they do them to detect colon cancer in someone who has no symptoms. There are other methods of screening for colon cancer, such as checking for occult blood in the stool, but if something looks suspicious on these tests, doctors often recommend a colonoscopy.
“Colonoscopy is ultimately the test that is done to evaluate colon cancer,” Dominitz said.
Dominitz helped CNN sort through the results of this new study to see what it means for you. Spoiler Alert: Colonoscopies Save Lives!
What did this new study show about the effectiveness of colonoscopies?
In this study, about 12,000 people in Sweden, Poland and Norway received colonoscopies. They saw a 31% reduction in the risk of colon cancer and a 50% reduction in the risk of dying from colon cancer compared to people who were not invited to have a colonoscopy.
Was this what you would expect?
Some US studies have suggested that colonoscopies are even more effective. One study followed nearly 90,000 health professionals for 22 years. Some of them chose to have a screening colonoscopy, and some did not. The researchers estimated that screening colonoscopy was associated with a 40% reduction in the risk of developing colon cancer and a 68% reduction in the risk of dying from colon cancer.
Why would there be different success rates in the three European countries compared to the US?
Dominitz says one reason could be that most people in the European study were not sedated when they had their colonoscopy. Only 23% of patients in the European study received sedation, but virtually everyone who had a colonoscopy in the US received it. Colonoscopies can be uncomfortable, and doctors may unknowingly be less thorough if people are in pain. Thoroughness (getting the scope into the folds and crevices of the colon) is important to find growths called polyps. The more polyps doctors can find, the more they can reduce a person’s risk of being diagnosed with or dying from colon cancer.
Bottom line: Should you still be screened for colon cancer?
Yes! Generally speaking, you should start getting regular colonoscopies at age 45. For people who are at high risk due to family history or other factors, it’s even younger; see these recommendations from the US Centers for Disease Control and Prevention and the American Cancer Society. And screening doesn’t have to involve a colonoscopy. There are other tests as well, but colonoscopy is the most common.
In the European study, people were invited to have colonoscopies. Why should they be invited? Colon cancer screening is not standard practice in these countries?
Only recently have Sweden, Poland and Norway begun screening their populations for colon cancer. Their programs began around 2015, and in the study, people were invited to have screening colonoscopies from 2009 to 2014. Patients were followed for about 10 years to see if they developed cancer colon
How many of the study participants said yes to the invitation to get a colonoscopy?
In the European study, 28,000 people aged 55 to 64 were invited to have a screening colonoscopy. Only 42% said yes.
Why so few?
Dominitz believes that’s partly because people in those countries weren’t used to the idea of getting screening colonoscopies. They hadn’t had them before, and their friends and family probably hadn’t either. Also, at the time of the study, there was no campaign to encourage colonoscopies, or Katie Couric (or Ryan Reynolds) to raise awareness about colon cancer.