A recent study in the Journal of the American Medical Association supports the thinking that many adults over 75—even those with a history of certain types of colonic polyps—may derive only limited benefit from continued screening colonoscopy. It’s clear that the decision to continue screening in older adults should be an individual one, based on multiple factors, and made in conversation with a trusted health provider.
Currently the United States Preventive Services Task Force (USPSTF) recommends screening for colorectal cancer in average-risk adults ages 45 to 75 every 10 years but only endorses selective screening for adults ages 76 to 85, looking at overall health, prior screening history, and preferences.
Colonoscopy is generally safe, but risks increase with age and frailty. Serious complications are uncommon but include bleeding, perforation of the colon, and anesthesia-related problems such as breathing difficulties, low blood pressure, adverse drug reactions, or, rarely, pneumonia aspiration. More common complications are typically milder and include dehydration from bowel preparation, temporary dizziness or weakness, bloating, cramping, and short-lived grogginess or confusion after sedation. Because of these risks, the study’s findings may help inform decisions about whether continued screening is worthwhile for older adults.
For the study, which was published in April, researchers analyzed records from nearly 92,000 older veterans who had undergone colonoscopy before age 75 and followed their outcomes for up to a decade. They found that older adults were far more likely to die from causes other than colorectal cancer—and that applied even to those with a history of adenomas, a type of polyp that can become cancerous.
Specifically, the 10-year risk of death from causes other than colorectal cancer was nearly 50 percent, whereas the risk of death from colorectal cancer was less than 1 percent. That was also true for those with prior adenomas.
Surprisingly, there was little difference between the participants who were previously diagnosed with advanced adenomas and those previously diagnosed with non-advanced adenomas. (Advanced adenomas are larger or more abnormal polyps that carry a higher risk of becoming cancerous.) Those with adenomas found on prior colonoscopies did have a slightly higher risk of colorectal cancer than those without adenomas (1.1 percent vs. 0.7 percent). But for both groups, colorectal cancer mortality remained low relative to mortality from other causes (0.5 percent vs. 0.4 percent).
The study had its limitations. Notably, its population was 98 percent male. Further research is needed to determine whether the results are applicable to women, who, on average, have longer life expectancies and a lower risk of colorectal cancer.
Current guidance
There are, in fact, differing opinions about when to stop screening: According to the Task Force the benefits of screening all persons ages 76 to 85 are small—although individuals who have never been screened have a greater benefit from screening. The American Cancer Society and American Academy of Family Physicians also recommend that screening should be individualized for older adults ages 76 to 85 and may be beneficial for individuals who are in excellent health and have a life expectancy of more than 10 years, especially if they had no prior screening. However, in 2023, the American College of Physicians recommended discontinuing screening in asymptomatic adults at average risk if they are older than 75 or have a life expectancy of 10 years or less; life expectancy is something individuals should discuss with their physicians.
The takeaway: The JAMA study raises major questions about screening colonoscopy in older adults, even with a history of prior adenomatous polyps. Age alone should not be the sole determinate in deciding when to stop colonoscopies. Adults 75 years and older should discuss the advisability of a screening colonoscopy with their doctor. Older adults, and particularly those who are frail, have a higher risk of dying from something other than colorectal cancer than they do from dying from the cancer. Additionally, they face increased risks from having a colonoscopy—from the bowel preparation and sedation required for the procedure. All this should be factored into a decision about whether or not to get additional screening colonoscopies. The presence of increased risks for colon cancer—including a family history of colon cancer and certain underlying diseases such as inflammatory bowel disease—should also be considered.
An option being studied is annual fecal immunochemical testing (FIT)—a well-established alternative colorectal cancer screening test that involves collecting a small stool sample for lab analysis—instead of colonoscopy, particularly in healthy older patients with a history of adenomatous polyps. This would be a noninvasive way of evaluating for serious colon lesions.
