Comparison of adenoma detection by colonoscopy between polypectomy performed during both insertion and withdrawal versus during withdrawal only: a multicenter, randomized, controlled trial

Background and aim: In standard colonoscopy, the colonoscope is inserted into the cecum, and inspection of the colonic mucosa and polypectomy are performed during withdrawal. The colon configuration can differ between the insertion and withdrawal phases, and some polyps found in the insertion phase can be missed during withdrawal. A few single-center studies investigated whether detection of polyps during the insertion phase affects the adenoma detection rate (ADR). However, the effectiveness of this strategy is unknown because of conflicting results. We aimed to determine whether polypectomy together with careful inspection during insertion increases the ADR compared with standard colonoscopy. Methods: A randomized, controlled, multicenter trial was conducted at three university hospitals. Patients aged 50 to 80 years were randomly assigned to the study group or control group. For patients in the study group, polypectomy was performed together with careful inspection during both colonoscope insertion and withdrawal. In the control group, polyps were inspected and removed only during colonoscope withdrawal. The primary endpoint was the ADR, which was defined as the percentage of patients with ≥ 1 adenoma. Results: A total of 1142 patients were enrolled (study group, n = 571; control group, n = 571). The ADR was similar in the 2 groups (study group, 44.1%; control group, 43.1%; P = 0.72). In the control group, 12 polyps that had been detected during colonoscope insertion were not found during withdrawal (polyp miss rate: 2.1%, 12/571). Conclusion: Polypectomy and careful inspection during both colonoscope insertion and withdrawal did not improve the overall ADR compared with standard colonoscopy (NCT01925833).