Patients with high-risk adenomas (HRAs) detected during colonoscopy should undergo an additional surveillance procedure even if intervening negative results are present, according to an observational study published in The American Journal of Gastroenterology.

Researchers recruited 891 participants from the observational study CSP #380. They gathered data from asymptomatic American veterans aged 50-75 years between 1994 and 1997. Participants had 3 or more colonoscopies at a minimum of 1-year intervals. HRA risk was evaluated in the third examination based on the previous 2 results.

HRAs were found in 12.8% (n=114) of third colonoscopy exams. Patients who had an HRA detected during the previous 2 exams were at highest risk for HRAs upon third examination (25.0%). Patients who had no HRA during their second endoscopy still had an increased odds ratio of HRA during follow-up screening at 3 years (OR, 3.41; 95% CI, 1.28-9.08), 5 years (OR, 3.14; 95% CI, 1.49-6.61), or 7 years (OR, 2.89; 95% CI, 1.08-7.74).

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The researchers observed a similar increased risk for HRAs during the third colonoscopy in patients who had at least 3 nonadvanced adenomas detected in their second colonoscopy which had been 3 years (OR, 4.61; 95% CI, 1.30–16.37), 5 years (OR, 6.37; 95% CI, 2.36–17.16), or 7 years (OR, 8.81; 95% CI, 2.26–34.26) prior to the third exam.

Limitations of the study included the study period and observational design. All colonoscopies were performed more than 20 years ago, and it remains unclear whether the results are generalizable to the colonoscopies of today. In addition, due to the study design, the intervals between exams varied greatly and were often shorter than current endoscopy guidelines.

The findings support current colorectal cancer surveillance guidelines. Patients who had an HRA during a first examination should proceed to have a third scan, even if no HRAs were found during their second colonoscopy.

Disclosures: Some authors declared receiving consulting or funding from the pharmaceutical industry. A complete list of disclosures can be found in the original study.


Sullivan B A, Redding T S, Hauser E R, et al. High-risk adenomas at screening colonoscopy remain predictive of future high-risk adenomas despite an intervening negative colonoscopy. [available online May 28, 2020]. Am J Gastroenterol. doi:10.14309/ajg.0000000000000677