Meta-analysis of narrow-band imaging versus conventional colonoscopy for adenoma detection

Background: At colonoscopy, missed adenomas have been well documented at approximately 22%. The challenge is in reducing this miss rate. Narrow-band imaging (NBI) has been extensively evaluated in prospective, randomized, controlled studies for polyp detection. Sample-size calculations show us that these studies may be underpowered, and hence a meta-analysis is required.

Objective: Our aim was to determine whether use of NBI enhances the detection of adenomas.

Design: Meta-analyses were conducted of 7 studies using NBI for adenoma detection rate. MEDLINE, Embase, PubMed, and Cochrane databases were searched by using a combination of the following terms: "colonoscopy," "NBI," and "electronic chromoendoscopy."

Patients: There was a total of 2936 patients in the NBI studies.

Interventions: Prospective, randomized trials of NBI versus standard white-light colonoscopy (WLC) were conducted. We excluded spray chromoendoscopy studies and studies of inflammatory bowel disease and polyposis syndromes.

Main outcome measurements: Adenoma and polyp detection rates and the number of polyps and adenomas detected per person.

Results: There was no statistically significant difference in the overall adenoma detection rate with the use of NBI or WLC (36% vs 34%; P = .413 [relative risk 1.06; 95% CI, 0.97-1.16]), and there was no statistically significant difference in polyp detection rate by using NBI or WLC (37% vs 35%; P = .289 [relative risk 1.22; 95% CI, 0.85-1.76]). When the number of adenomas and polyps per patient was analyzed, no significant difference was found between NBI and WLC (0.645 vs 0.59; P = .105 and 0.373 vs 0.348; P = .139 [weighted mean difference 0.19; 95% CI, ∞0.06 to 0.44], respectively).

Limitation: Variability in NBI studies can reduce the accuracy of this analysis.

Conclusions: NBI did not increase adenoma or polyp detection rates.