Comparison of polyp detection during both insertion and withdrawal versus only withdrawal of colonoscopy: A prospective randomized trial

Background and Aims: Polyps seen and not removed during colonoscope insertion are sometimes unable to be found during withdrawal. We aimed to evaluate whether additional inspection and polypectomy during insertion increases adenoma detection rate (ADR) compared with inspection and polypectomy entirely during withdrawal. Methods: A total of 421 patients aged ≥ 45 years and undergoing colonoscopy were prospectively randomized to receive inspection and polypectomy during both insertion and withdrawal (study group) or inspection and polypectomy entirely during withdrawal (control group). The primary outcome was the ADR. Secondary outcomes included other adenoma-related parameters and procedure-related measures. Results: Baseline demographics, procedure indications, preparation quality, total procedure time, sedative doses, colonoscopy difficulty, and patient discomfort were similar between the groups. The insertion time was significantly longer in the study group (11.1 ± 4.8 vs 6.2 ± 4.7 min, P < 0.0001). The withdrawal time was significantly longer in the control group (29.2 ± 9.8 vs 23.1 ± 7.9 min, P < 0.0001). There was no significant difference in the ADR (63.5% [study group] vs 68.1% [control group]), the mean adenoma per procedure (1.6 ± 2.0 vs 1.9 ± 2.4), or the mean adenoma per positive procedure (2.5 ± 2.0 vs 2.7 ± 2.5) between groups. The proximal colon ADR was significantly higher in the control group compared with the study group (56.2% vs 46.0%, P = 0.041). Conclusions: Additional inspection and polypectomy during colonoscope insertion did not improve ADR compared with inspection and polypectomy entirely during withdrawal. These results do not support an additional role for routine inspection during insertion (clinical trial registration number: NCT03444090).