Proximal retroflexion versus second forward view of the right colon during screening colonoscopy: A multicentre randomized controlled trial.

Background: Colonoscopy is the gold standard investigation for the detection of colorectal cancer, but the right colon is more difficult to examine than the left colon. A second examination of the proximal colon has the potential to reduce rates of missed pathology.

Objective: To determine whether proximal retroflexion improves the adenoma detection rate or other outcomes in the right colon compared with the forward view.

Methods: We performed a multicentre randomized controlled trial of patients from the colorectal cancer screening programme with a positive faecal immunochemical test. Patients were randomized to a second right colon examination using proximal retroflexion or forward view.

Results: A total of 692 patients were included. A second examination of the right colon, with an average additional procedure time of 1.62 min, increased the adenoma detection rate by 11%, regardless of the method used (9% proximal retroflexion . 12% second forward view,  = 0.21). The adenoma miss rate was 19% (17% proximal retroflexion . 20% forward view,  = 0.28) The success rate of retroflexion was 83%, without secondary complications. In the 15.6% of patients in whom lesions were detected during the second pass, endoscopic follow-up was modified by reducing the time of the next colonoscopy.

Conclusions: A second examination of the right colon, either from retroflexion or second forward view, can increase adenoma detection rate and shorten surveillance intervals in patients undergoing screening colonoscopy. This should be emphasized during colonoscopy training and integrated into diagnostic colonoscopy practice.