Objective Colonoscopy, the gold standard colorectal cancer (CRC) screening test, has known diagnostic limitations. Advances in endoscope technology have focused to improve mucosal visualization. In addition to increased angle of view and resolution features, recent colonoscopes have non-white light optics, such as Narrow Band Imaging (NBI), to enhance image contrast. We aimed to study the neoplasia diagnostic characteristics of NBI, by comparing the neoplasm miss rate when the colonoscopy was performed under NBI versus white light (WL).
Design Randomized controlled trial.
Setting US Veterans hospital.
Patients Elective colonoscopy adults.
Intervention We randomly assigned patients to undergo a colonoscopic examination using NBI or WL. All patients underwent a second examination using WL, as the reference standard.
Main outcome measures The primary end point was the difference in the neoplasm miss rate, and secondary outcome was the neoplasm detection rate.
Results In 276 tandem colonoscopy patients, there was no significant difference of miss or detection rates between NBI or WL colonoscopy techniques. Of the 135 patients in the NBI group, 17 patients (12.6%; 95%CI:7.5-19.4%) had a missed neoplasm, as compared with 17 of the 141 patients (12.1%; 95%CI:7.2-18.6%) in the WL group, with a miss rate risk difference of 0.5% (95%CI: -7.2 - 8.3). 130 patients (47%) had at least 1 neoplasm. Missed lesions with NBI showed similar characteristics to those missed with WL. All missed neoplasms were tubular adenomas, the majority (78%) was ≤5 mm and none were larger than 1 cm (one sided 95%CI: up to 1%). Nonpolypoid lesions represented 35% (13/37) of missed neoplasms.
Interpretation NBI did not improve the colorectal neoplasm miss rate compared to WL - the miss rate for advanced adenomas was less than 1% and for all adenomas was 12%. The neoplasm detection rates were similarly high using NBI or WL -almost a half of the study patients had at least one adenoma. ClinicalTrials.gov Identifier: NCT00628147.