Study measures risks of screening colonoscopies for older adults

The findings can help guide colorectal cancer screening decisions later in life

A new study sheds light on the potential harms of screening colonoscopies for adults ages 76 to 85, finding a small increase in risk for hospitalization and death in the weeks after the procedure.

“Few previous studies have looked at the risks of screening colonoscopies for this older age group,” said lead author Jessica Chubak, PhD, a senior investigator with Kaiser Permanente Washington Health Research Institute (KPWHRI). “This study addresses an important gap in the research about this widely used method of screening for colorectal cancer.”

What do we know already?

Colonoscopies are one of the most effective screening methods for detecting early colorectal cancer as well as precancerous polyps. The procedure involves a doctor using a long, flexible tube with a camera to look inside the colon.

The U.S. Preventive Services Task Force recommends that adults ages 45 to 75 have regular colorectal cancer screening, usually with a colonoscopy every 10 years or with stool-based tests every year. After age 75, however, the recommendations are more cautious, advising that screening decisions be made on an individual basis through age 85 (after which screening is no longer recommended). This reflects concern about whether the benefits of screening colonoscopies outweigh the chance of bleeding and other harms as people get older. The new study assessed whether there is evidence to support this concern.

What did the new study find?

Chubak and her team looked at data on 4,435 patients ages 76 to 85 who had a screening colonoscopy from 2010 to 2019. They compared them with over 30,000 patients of the same age who did not have a colonoscopy on specific dates during this time period. All the people in the study were members of Kaiser Permanente Washington, Kaiser Permanente Southern California, and Kaiser Permanente Northern California.

Among people who had a screening colonoscopy, 2.3% died or were hospitalized overnight within 30 days, compared with 1.17% of those who did not have a colonoscopy.

Other analyses suggested that the colonoscopy itself didn’t substantially increase people’s risk of death or hospitalization. Instead, the colonoscopy may have led to subsequent procedures that increased the chance of harm for older patients.

“For people ages 76 to 85 who are considering having a screening colonoscopy, these findings provide a clearer picture of the potential risks,” Chubak said. “This should help patients make better-informed decisions with their doctors about whether the benefits of this screening method outweigh the risks for them.”

The study was published in Cancer Epidemiology Biomarkers and Prevention. It was funded by the National Cancer Institute.

KPWHRI coauthors included Laura Ichikawa, MS; Rebecca Ziebell, BS; and Beverly Green, MD, MPH.

By Sophie Ramsey