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The Effect of Right Colon Retroflexion on Adenoma Detection: A Systematic Review and Meta-analysis

Cohen, Jonah MD; Grunwald, Douglas MD; Grossberg, Laurie B. MD; Sawhney, Mandeep S. MD, MS

Journal of Clinical Gastroenterology: October 2017 - Volume 51 - Issue 9 - p 818–824
doi: 10.1097/MCG.0000000000000695
ALIMENTARY TRACT: Original Articles

Background: Although colonoscopy with polypectomy can prevent up to 80% of colorectal cancers, a significant adenoma miss rate still exists, particularly in the right colon. Previous studies addressing right colon retroflexion have revealed discordant evidence regarding the benefit of this maneuver on adenoma detection with concomitant concerns about safety and rates of maneuver success. In this meta-analysis, we sought to determine the effect of right colon retroflexion on improving adenoma detection compared with conventional colonoscopy without retroflexion, as well as determine the rates of retroflexion maneuver success and adverse events.

Methods: Multiple databases including MEDLINE, Embase, and Web of Science were searched for studies on right colon retroflexion and its impact on adenoma detection compared with conventional colonoscopy. Pooled analyses of adenoma detection and retroflexion success were based on mixed-effects and random-effects models with heterogeneity analyses.

Results: Eight studies met the inclusion criteria (N=3660). The primary analysis comparing colonoscopy with right-sided retroflexion versus conventional colonoscopy to determine the per-adenoma miss rate in the right colon was 16.9% (95% confidence interval, 12.5%-22.5%). The overall rate of successful retroflexion was 91.9% (95% confidence interval, 86%-95%) and rate of adverse events was 0.03%.

Conclusions: Colonoscopy with right-sided retroflexion significantly increases the detection of adenomas in the right colon compared with conventional colonoscopy with a high rate of maneuver success and small risk of adverse events. Thus, reexamination of the right colon in retroflexed view should be strongly considered in future standard of care colonoscopy guidelines for quality improvement in colon cancer prevention.

Supplemental Digital Content is available in the text.

Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA

J.C. received funding for this research from an NIH T32 grant.

The authors declare that they have nothing to disclose.

Address correspondence to: Mandeep S. Sawhney, MD, MS, Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Rabb-Rose 101, Boston, MA 02215 (e-mail:

Received April 29, 2016

Accepted August 8, 2016

Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.