Screening for disease is not as straightforward as it may seem on cursory examination. Sometimes it does not influence the course of the screened for disease and other times it may cause more harm than good as early intervention may result in more morbidity than if the disease had been undiagnosed. Then there is the issue of the age of the population to be screened. Obviously, the older the population the less they have to gain even from an effective screening procedure.
Screening for colon cancer is generally accepted as useful and effective. Mortality from the disease has decreased over the past 30 years. This observation suggests that screening and early diagnosis of premalignant lesions have been effective. But complicating this view is that the incidence of the disease has also fallen for unclear reasons. See Cancer Statistics 2024.
Let’s, however, assume that identifying premalignant lesions is useful and focus on the question of at what age should colonoscopy in patients already known to have such lesions be stopped. This issue was examined in Surveillance Colonoscopy Findings in Older Adults With a History of Colorectal Adenomas published by the JAMA Open Network. The complete paper is available for download below.
The patients studied were 70 to 85 years of age who received surveillance colonoscopy at a large, community-based US health care system between January 1, 2017 and December 31, 2019; had an adenoma detected 12 or more months previously; and had at least 1 year of health plan enrollment before surveillance. Individuals were excluded due to prior colorectal cancer (CRC), hereditary CRC syndrome, inflammatory bowel disease, or prior colectomy or if the surveillance colonoscopy had an inadequate bowel preparation or was incomplete.
Advanced neoplasia was defined as any CRC or advanced adenoma. Advanced adenoma was defined as a conventional adenoma with high-grade dysplasia or villous or tubulovillous histologic features or as any conventional adenoma 10 mm or greater in size.
In a large, integrated health care system, among 9740 surveillance colonoscopies in patients 70 to 85 years of age with a history of colorectal adenoma, detection of CRC or advanced neoplasia did not increase significantly with age over five years of observation. Overall, CRC detection was rare (0.3%), while detection of advanced neoplasia was more common (12.0%). Patients with a history of advanced adenoma vs nonadvanced adenoma were more likely to have CRC detected, though still rarely (0.5% vs 0.2%), and were more likely to have advanced neoplasia detected (16.5% vs 10.6%).
The two figures below summarize the study’s findings. NAA is non-advanced adenoma. AA is advanced adenoma. The first figure depicts the incidence of CRC while the second shows the incidence of advanced neoplasia. Notice how low was the incidence of cancer.
The very low incidence of CRC in elderly subjects with adenomas regardless of type suggests that there should be some age at which the risks of colonoscopy exceed any benefit. These risks increase with age, particularly among those aged 75 years or older, and include heart attack, stroke, sedation-related adverse events (eg, aspiration pneumonia), bleeding, infection, and perforation. The data in this study suggest that elderly people with adenomas considered to be at high risk of CRC are actually not at very high risk. And that the procedure should be limited to those with a life expectancy of at least 10 years. Both 80 year men and women in the US have life expectancies of less than 10 years. Those younger with comorbidities will also fall into this group.
The obvious next question is what about routine colonoscopy in people who do not have adenomas? At what age should colonoscopy no longer be recommended? Current guidelines provide no direction as to what age the procedure should be stopped in patients with or without lesions. Any recommendation I would make as to what age the scope should remain in the cabinet would be pure speculation, but my guess is that age 65 to 70 would be a good time to discard routine colonoscopy in patients with no lesions.
