Narrow band imaging colonoscopy is not better than white light colonoscopy in detecting the patients with colorectal polyps.

Cancer of the large bowel is the third most common cancer worldwide. It has been suggested that colorectal polyps are precursors of colorectal cancer. Consequently, early detection and removal of colorectal polyps is important in secondary prevention of colorectal cancer. A number of randomised trials comparing narrow band imaging colonoscopy (a high resolution endoscopic technique that enhances the fine structure of the mucosal surface) with white light colonoscopy for detection of colorectal polyps reported variable results.

This review analysed the role of narrow band imaging colonoscopy compared to the white light colonoscopy for detection of colorectal polyps. In total eight randomised trials with 3673 participants were able to provide data for our analyses. Narrow band imaging colonoscopy was not better than high definition white light colonoscopy for the detection of patients with colorectal polyps. We found weak evidence that narrow band imaging colonoscopy could be better than conventional white light colonoscopy for detection of patients with colorectal polyps.

Authors' conclusions: 

We could not find convincing evidence that NBI is significantly better than high definition WLC for the detection of patients with colorectal polyps, or colorectal adenomas. We found evidence that NBI might be better than standard definition WLC and equal to high definition WLC for detection the patients with colorectal polyps, or colorectal adenomas.

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Background: 

It has been suggested that narrow band imaging colonoscopy (NBI) might be better for detection of colorectal polyps than white light colonoscopy (WLC).

Objectives: 

To compare standard or high definition white light colonoscopy with narrow band imaging colonoscopy for detection of colorectal polyps.

Search strategy: 

We searched The Cochrane Library, MEDLINE, and EMBASE to August 2011. We scanned bibliographies of relevant publications and wrote to experts for additional trials.

Selection criteria: 

Two authors (NA and GB) independently applied the inclusion criteria and extracted the data to all potential studies without blinding.

Data collection and analysis: 

Authors extracted data independently. Trials with adequate randomisation, allocation concealment, and complete outcome data reporting, as well as without selective outcome reporting or other bias were classified as having a lowest risk of bias. Random-effects and fixed-effect meta-analyses were conducted.

Main results: 

We identified 11 randomised trials comparing WLC with NBI for detection of colorectal polyps. In total eight randomised trials with 3673 participants provided data for our analyses. There was no statistically significant difference between WLC (standard definition and high definition pooled) and NBI for the detection of patients with colorectal polyps (6 trials, n = 2832, RR 0.97, 95% CI 0.91 to 1.04), patients with colorectal adenomas (8 trials, n = 3673, RR 0.94, 95% CI 0.87 to 1.02), or patients with colorectal hyperplastic polyps (2 trials, n = 645, RR 0.87, 95% CI 0.76 to 1.00). Number of patients with at least one colorectal adenoma was not significantly different between WLC and NBI group irrespective of adenoma size (< 5 mm:RR 0.95, 95% CI 0.84 to 1.08, I2 = 56%; 6 to 9 mm: RR 1.06, 95% CI 0.81 to 1.39, I2 = 0%; ≥ 10 mm: RR 1.06, 95% CI 0.77 to 1.45, I2 = 0%). Number of patients with at least one colorectal polyp, or colorectal adenoma was significantly lower in the standard definition WLC group compared to NBI group in fixed-effect meta-analysis (RR 0.87, 95% CI 0.78 to 0.97, I2 = 78%; RR 0.87, 95% CI 0.77 to 0.99, I2 = 0%, respectively), but not significantly different in random-effects meta-analysis (RR 0.86, 95% CI 0.68 to 1.10, I2 = 78%). There was no statistically significant difference between high definition WLC and NBI in the number of patiens with at least one colorectal polyp or colorectal adenoma (RR 1.10, 95% CI 0.95 to 1.28; RR 0.87, 95% CI 0.77 to 0.99, I2 = 0%, respectively).

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