Increasing adenoma detection rates in the right side of the colon comparing retroflexion with a second forward view: a systematic review

Background and aims: Right-sided lesions are often missed during standard colonoscopy (SC). A second forward-view examination or retroflexion in the right side of the colon have both been proposed as techniques to improve adenoma detection rate (ADR) in the right side of the colon. Comparative data on examining the right side of the colon with a second forward view or retroflexion is not known in a pooled analysis. We performed a systematic review of the literature to assess the yield of a second forward view compared with retroflexion examination for the detection of right-sided adenomas.

Methods: A systematic literature search was performed using the following databases: PubMed, Embase, Web of Science, and Cochrane. Only full-length published articles that provided information on adenoma detection and miss rates during either a second forward view or retroflexed view of the right side of the colon after the initial standard forward withdrawal (SC) were included. The following outcomes were assessed: comparison of adenoma miss rate (AMR) for second forward view versus retroflexion after SC, AMR of SC compared with second forward view, AMR of SC compared with retroflexion, and right-sided adenoma detection with second forward view and retroflexion. Pooled rates were reported as risk difference or odds ratios (OR) with 95% confidence intervals (CI) with a P value <.05 indicating statistical significance. Statistical analysis was performed with Review Manager v5.3.

Results: We identified 4 studies with 1882 patients who underwent a second forward view of the right side of the colon after an initial SC. The average age of the patients was 58.3 years. Data on right-sided ADR were available from all 4 studies for the second forward view; however, only 2 of the studies provided information on right-sided ADR with retroflexion. The pooled estimate of AMR of a single SC was 13.3% (95% CI, 6.6%-20%) compared with a second forward-view examination (n = 4), whereas it was 8.1% (3.7%-12.5%) compared with a retroflexion examination (n = 3). However, when the second forward view was compared with retroflexion in terms of AMR from an analysis of 3 eligible studies, there was no statistically significant difference (7.3% vs 6.3%; pooled OR, 1.2; 95% CI, 0.9-1.61; P = .21). Second forward view of the right side of the colon increased the right-sided ADR by 10% (n = 4; second forward view vs SC, 33.6% vs 26.7%) with a pooled risk difference of 0.09 (95% CI, 0.03-0.15; P < .01). Retroflexion increased the right-sided ADR by 6% (n = 3; retroflexion vs SC, 28.4% vs 22.7%) with a pooled risk difference of 0.06 (95% CI, 0.03-0.09; P < 01).

Conclusion: After SC withdrawal, a second forward view and retroflexed view of the right side of the colon are both associated with improvement in ADR. One of these techniques should be considered during SC to increase ADR and to improve the quality of colonoscopy.