Yield of Repeat Forward-view Examination of the Right Side of the Colon in Screening and Surveillance Colonoscopy

Background And Aims: Colonoscopy is less protective for cancers of the right side of the colon than for distal colon cancers. Repeat examination of the right side of the colon has been suggested to increase adenoma detection and potentially provide greater protection against the development of cancers of the right side of the colon. Our prospective study assessed the yield of a second forward-view examination of the right side of the colon done immediately after the initial examination.

Methods: All men 50 to 75 years of age undergoing screening or surveillance colonoscopy at the West Haven Veterans Affairs Medical Center were invited to participate. A second forward-view examination was performed if the Boston Bowel Preparation Scale score was 8 to 9 (scale = 0-9) with right a side of the colon segment score of 2 to 3 (scale = 0-3). The primary outcome was the per-patient adenoma detection rate (including sessile serrated polyps) on a repeated examination of the right side of the colon, defined as the number of patients with ≥1 adenoma on the second examination of the right side of the colon divided by total number of patients. An increase in the adenoma detection rate (ADR) was a secondary outcome.

Results: Repeated examination of the right side of the colon, performed in 280 patients, revealed additional adenomas in 43 patients (15.4%; 95% confidence interval [CI] of difference, 11.3%-21.0%). The overall ADR increased by 3.2% (95% CI, 1.1%-5.3%) after the second examination of the right side of the colon; the ADR for the right side of the colon increased by 6.7% (95% CI, 3.8%-9.7%). Ten patients (3.6%) had a change in their screening/surveillance interval with the addition of findings on the second examination of the right side of the colon.

Conclusion: A substantial 15.4% of patients had additional adenomas detected on a second forward-view examination of the right side of the colon, whereas the overall ADR increased significantly by 3.2%. Given the lack of additional training or equipment required, repeated forward-view examination of the right side of the colon is a simple, readily available method to achieve a modest improvement in the ADR.