Systematic review and meta-analysis of narrow band imaging for non-muscle-invasive bladder cancer

To assess the effect of narrow band imaging-guided transurethral resection of bladder tumor compared with white light on recurrence rates in non-muscle-invasive bladder cancer. A systematic review of the literature from inception to November 2020 using Medline, EMBASE and CENTRAL was undertaken. Randomized controlled trials comparing transurethral resection of bladder tumor undertaken with narrow band imaging with those undertaken with white light that reported recurrence rates of at least 12 months were included in the analysis. Primary outcomes were recurrence rates at 12 and 24 months. Secondary outcomes were reported adverse effects. A total of 387 abstracts were screened, of which 14 full text identified and three studies included in the meta-analysis (921 patients). Meta-analysis did not show a statistically significant benefit to narrow band imaging at 12 months; risk ratio 0.75 (95% confidence interval 0.50-1.14, P = 0.18, I-2 = 61%). No included studies provided recurrence data beyond 12 months. Adverse effects were reported in one study and no significant difference of complication rate was observed between the two groups. Risk of bias was assessed to be generally low, and grading of recommendations assessment development and evaluations were of high certainty. This meta-analysis of randomized controlled trials shows no difference in recurrence rates using narrow band imaging, although a trend in its favor was identified. Limitations include the varied reporting and administration of adjuvant therapies. Further well-designed trials are required to examine the benefit of this technology.