Evidence for Variation in the Number of Colonoscopies Required To Achieve a Clear Colon

Evidence for Variation in the Number of Colonoscopies Required To Achieve a Clear Colon

Douglas K. Rex, MD, MASGE, reviewing Juul FE, et al. Gut 2022 Oct 28.

Ideally, patients presenting for colonoscopy should have a complete examination and identification and resection of all precancerous polyps in a well-prepared colon, followed by assignment to an appropriate surveillance interval, and all after a single colonoscopy. Variations in the assessment of bowel preparation quality or unwillingness to clear multiple polyps from the colon could result in repeated colonoscopies to complete initial clearance, which results in increased costs and burden to patients and health care systems.

The European Polyp Surveillance I and II trials are multicenter, multinational studies of surveillance in patients with low-risk adenomas (1 or 2 small tubular adenomas) and high-risk adenomas (3-10 adenomas ≥10 mm, high-grade dysplasia or villous patterns), respectively. The current study looked at variation among centers in the number of colonoscopies needed to achieve initial clearance before entry into randomized surveillance studies. 

Among 15,581 patients from 5 countries and 38 endoscopy centers, 1.5% of those with low-risk adenomas and 9.8% of those with high-risk adenomas underwent 2 or more baseline colonoscopies to complete initial clearance. The need for repeat colonoscopy varied from 0% to 11.8% across study centers for patients with low-risk adenomas and 0% to 63.9% among patients with high-risk adenomas. 

In the low-risk adenoma cohort, polyps left in situ (32.7%) and poor bowel preparation (31.7%) were the most common reasons for repeat colonoscopies. In the high-risk adenoma cohort, the most common reasons were polyps left in situ (27.2%), poor bowel preparation (20.1%), and piecemeal polyp resection (13.8%).

In the discussion, the authors commented that a root cause analysis performed by interviewing individual centers indicated that endoscopists who were overly cautious, wanting a check to ensure the colon was clear before surveillance, was the most common overall cause of repeat colonoscopies.

Douglas K. Rex, MD, FASGE


These data suggest that the number of polyps colonoscopists are willing to remove in 1 colonoscopy could become the target of quality improvement efforts.

Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.


Juul FE, Garborg K, Nesbakken E, et al. Rates of repeated colonoscopies to clean the colon from low-risk and high-risk adenomas: results from the EPoS trials. Gut 2022 Oct 28. (Epub ahead of print) (https://doi.org/10.1136/gutjnl-2022-327696)

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