Results of a second examination of the right side of the colon in screening and surveillance colonoscopy: a systematic review and meta-analysis

Background Screening colonoscopy is less effective in preventing proximal colon cancers than distal colon cancers. A repeat examination of the right side of the colon may increase the lesion detection. The study aimed to assess the results of a second examination of the right side of the colon with forward-view or retroflexion colonoscopy performed immediately after the initial examination. Materials and methods We carried out a meta-analysis of all primary studies that performed a second examination of the right side of the colon with forward-view or retroflexion colonoscopy performed immediately after the initial examination. Results Six cohorts of five studies with 4155 participants were included in the final study. The adenoma detection rate (ADR) was 28.8% of the combined examinations compared with 24.1% of the single examination (P < 0.001), for a pooled odds ratio of 1.34 [95% confidence interval (CI): 1.13-1.59]. For retroflexion assessment, ADR was achieved in 25.4% patients in the combined group, compared with 22.3% in the single examination group (P = 0.002), for a pooled odds ratio of 1.19 (95% CI: 1.06-1.33). For forward-view assessment, ADR was achieved in 46.0% patients in the combined group, compared with 33.5% in the single examination group (P < 0.001), for a pooled odds ratio of 1.76 (95% CI: 1.40-2.22). Conclusion For ADR of the right side of the colon, a repeat examination could lead to a modest improvement in the detection of lesions in the proximal colon, irrespective of forward-view or retroflexion assessment. Copyright (C) 2018 Wolters Kluwer Health, Inc. All rights reserved.