Colonoscopies may need to be done only every 15 years for some people. Here’s why.

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Experts say a colonoscopy remains the most effective way to detect colorectal cancer. stefanamer/Getty Images
  • Researchers report that the period between colonoscopies can be extended from 10 to 15 years for people with an initial negative screening and no family history of colorectal cancer.
  • They said extending the time period between colonoscopies for this group would only miss two colorectal cancer cases per 1,000 individuals.
  • Experts note that colorectal cancer screenings are still vital as this deadly disease is treatable if caught early.

Colonoscopies may not need to be performed for some people as frequently as previously believed, according to a study published today in the journal JAMA Oncology.

Researchers say the commonly accepted 10-year period between colonoscopies could be expanded to 15 years for people with a negative initial screening and no family history of colorectal cancer.

The cohort study out of Sweden looked at 110,074 individuals with no family history of colorectal cancer and negative results on their first screening as an “exposed” group, compared to 1,981,332 matched individuals in a control group.

In the first group, risks of colorectal cancer and colorectal cancer-specific death were lower for 15 years, suggesting that extending the screening interval from 10 to 15 years would miss only two colorectal cases and only one colorectal cancer-related death per 1,000 individuals.

The researchers looked at data from Swedish nationwide register to examine colorectal cancer diagnoses and colorectal cancer-specific mortality among individuals without a family history of the disease. Individuals with inflammatory bowel disease were excluded from the study.

The exposed group included people who had their first colonoscopy with negative findings at ages 45 to 69 years between 1990 and 2016.

The control group included people matched by gender, birth year, and baseline age (the age of their matched exposed individual when the exposed individual’s first negative colonoscopy was performed).

People in the control group either didn’t have a colonoscopy during the follow-up or underwent a colonoscopy that resulted in a colorectal cancer diagnosis.

Up to 18 control factors were matched with each exposed individual. Researchers followed up with subjects from 1990 to 2018 and data was analyzed from November 2022 to November 2023.

Of the 110,074 people in the exposed group, 59% were females. In the control group, 59% of the group was also female.

The median age in both groups was 59 years. During up to 29 years of follow-up with people with an initial negative colonoscopy, 484 colorectal cancer diagnoses and 112 cancer-specific deaths occurred.

After a first colonoscopy with a negative finding, the risks of colorectal cancer and colorectal cancer-specific death in the exposed group were significantly lower than those in their matched controls for 15 years.

The 10-year cumulative risk of colorectal cancer in year 15 in the exposed group was 72% that of the 10-year cumulative risk of colorectal cancer in the control group.

The researchers said extending the colonoscopy screening interval from 10 to 15 years in people with a first negative colonoscopy would miss the early detection of only two colorectal cases and the prevention of one cancer-specific death.

The researchers also said the 10-year interval between colonoscopy screenings for those with negative first screenings could potentially be extended to 15 years.

“A longer interval between colonoscopy screenings could be beneficial in avoiding unnecessary invasive examinations,” researchers said.

In pointing out the importance of colorectal cancer screenings, the research team highlighted that colorectal cancer “is a major public health challenge, being the third most common cancer and the second most common cause of cancer deaths in the world.”

The researchers did concede that “there is limited evidence supporting this specific time interval for repeat colonoscopy.”

Dr. Anton Bilchik is a surgical oncologist, the chief of medicine, and the director of the Gastrointestinal and Hepatobiliary Program at Providence Saint John’s Cancer Institute in California.

Bilchik, who was not involved in the research, told Medical News Today the research is a cohort study and therefore the results need to be interpreted cautiously.

“It is neither a prospective study nor is it a randomized trial,” Bilchik said. “Given the rapid increase in early onset colorectal cancer many new cases are likely to be missed. This study does not control for missed polyps and/or cancers that occur 10 to 15 percent of the time, which may be detected with more frequent colonoscopies.”

Bilchik also said the study doesn’t discuss stool-based tests, which he said are sensitive, inexpensive, and can be considered as an alternative in this cohort of people.

“Since they provide no data on how colonoscopies done every 15 (years) rather than 10 may reduce complications, it is not clear what the benefit is in reducing colonoscopies,” Bilchik said.

He noted that screening rates for colorectal cancer vary from 20% to 60% depending on socioeconomics and the area in which the subjects live, screening rates that are lower than goal.

“The national goal is 80 percent,” Bilchik said. “This study may be interpreted incorrectly, further reducing the need for colonoscopy and/or stool tests, which have been shown to save many lives by removing precancerous polyps or detecting colon cancer at an early stage.”

Dr. Dale Whitebloom, the chief medical officer at digestive health provider U.S. Digestive Health who was not involved in the research, told Medical News Today that colorectal cancer is the second deadliest cancer, but there are many available treatments when it is caught at an early stage.

“As we’re starting to see an alarming increase of cases of colon cancer in young people, it’s vitally imperative that [gastrointestinal] doctors and researchers continue to stress the importance of early detection and screening – awareness is an important tool to have in our tool kit,” Whitebloom said.

“It’s vital for individuals – including younger people — to be aware of early signs and symptoms, understand the risk for younger people, have the most up-to-date recommendations, and have access to most effective screening tools.”

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