Diagnostic yield of scope retroflexion in the right colon: A prospective cohort study

Techniques have been implemented to improve colonoscopy adenoma detection rate (ADR) in the right colon.

We prospectively examined the additional diagnostic yield of right colon examination with colonoscope retroflexion in consecutive, symptomatic and screening-surveillance patients. Right colon was examined in forward-view first and thereafter, retroflexion was performed to re-inspect it.

Right colon examination in retroflexion was achieved in 620 (92%) patients. Increased inserted scope length to the cecum (OR: 0.48 [95% CI: 0.27-0.84]) and elderly status (OR: 0.53 [95% CI: 0.430-0.94]) predicted retrofexion failure. Forward-view colonoscopy detected 134 polyps and 112 adenomas in 105 and 85 patients, respectively. Scope retroflexion revealed 7 missed (6 adenomas--2 advanced) polyps in 7 patients; indicating 4.96 (95% CI: 1.37-8.55) % and 5.1 (95% CI: 1.12-9.05) % per-polyp and per-adenoma miss rates, respectively. In ITT analysis, per-patient polyp and adenoma miss rates were 1.041% and 0.89%, respectively. Among screening-surveillance patients, retroflexion detected 3 missed adenomas (2 advanced) in 3 patients, resulting in changed surveillance schedule in 2 of them (5.12 per 1000 screening-surveillance patients). Early study termination was favored by low right colon ADR improvement and lacking substantial surveillance interval change.

The additional diagnostic yield of scope retroflexion in the right colon is questionable.