Narrow-band imaging does not improve detection of colorectal polyps when compared to conventional colonoscopy: a randomized controlled trial and meta-analysis of published studies

Background: A colonoscopy may frequently miss polyps and cancers. A number of techniques have emerged to improve visualization and to reduce the rate of adenoma miss. Methods: We conducted a randomized controlled trial (RCT) in two clinics of the Gastrointestinal Department of the Sanitas University Foundation in Bogota, Colombia. Eligible adult patients presenting for screening or diagnostic elective colonoscopy were randomlsy allocated to undergo conventional colonoscopy or narrow-band imaging (NBI) during instrument withdrawal by three experienced endoscopists. For the systematic review, studies were identified from the Cochrane Library, PUBMED and LILACS and assessed using the Cochrane risk of bias tool. Results: We enrolled a total of 482 patients (62.5% female), with a mean age of 58.33 years (SD 12.91); 241 into the intervention (NBI) colonoscopy and 241 into the conventional colonoscopy group. Most patients presented for diagnostic colonoscopy (75.3%). The overall rate of polyp detection was significantly higher in the conventional group compared to the NBI group (RR 0.75, 95% CI 0.60 to 0.96). However, no significant differences were found in the mean number of polyps (MD -0.1; 95% CI -0.25 to 0.05), and the mean number of adenomas (MD 0.04 95% CI -0.09 to 0.17). Meta-analysis of studies (regardless of indication) did not find any significant differences in the mean number of polyps (5 RCT, 2479 participants; WMD -0.07 95% CI -0.21 to 0.07; I2 68%), the mean number of adenomas (8 RCT, 3517 participants; WMD -0.08 95% CI -0.17; 0.01 to I2 62%) and the rate of patients with at least one adenoma (8 RCT, 3512 participants, RR 0.96 95% CI 0.88 to 1,04; I2 0%). Conclusion: NBI does not improve detection of colorectal polyps when compared to conventional colonoscopy (Australian New Zealand Clinical Trials Registry ACTRN12610000456055).