Aim: To investigate the value of retroflexion in detecting neoplasia in the distal rectum.
Methods: This was a prospective observational study performed in an academic endoscopy unit. Consecutive patients undergoing colonoscopy had careful forward viewing of the distal rectum by retroflexion. Of 1502 procedures, 1076 (72%) procedures were performed with a 140 degrees angle of view colonoscope and 426 (28%) were performed with a 170 degrees angle of view colonoscope. The outcome measurement was the yield of neoplasia in the distal rectum detected by forward viewing vs retroflexion.
Results: A total of 1502 patients, including 767 (51%) females and 735 (49%) males, with mean age of 58.8 +/- 12.5 years were enrolled. Retroflexion was successful in 1411 (93.9%) patients, unsuccessful or not performed because the rectum appeared narrow in 91 (6.1%). Forty patients had a polyp detected in the distal rectal mucosa. Thirty-three were visible in both the forward and retroflexed view (25 hyperplastic, 8 adenomatous). Seven polyps were visualized only by retroflexion (6 hyperplastic sessile polyps, one 4 mm sessile tubular adenoma). There was no significant difference in information added by retroflexion with 140 degrees vs 170 degrees angle of view instrument.
Conclusion: To our knowledge, this is the largest reported evaluation of retroflexion in the rectum. Routine rectal retroflexion did not detect clinically important neoplasia after a careful forward examination of the rectum to the dentate line. Since retroflexion has risks and may cause discomfort, the use of routine retroflexion should be at the discretion of the endoscopist.