A meta-analysis of narrow band imaging for the diagnosis and therapeutic outcome of non-muscle invasive bladder cancer

To assess the additional detection rate (ADR) of within-patient comparisons of Narrow band imaging (NBI) and white light cystoscopy (WLC) for non-muscle invasive bladder cancer (NMIBC) detection and compare the impact of NBI and WLC on bladder cancer recurrence risk. We searched relevant studies from PubMed, Embase, Medline, Web of Science and the Cochrane Library database for all articles in English published beforeJuly26th, 2016. Pooled ADR, diagnostic accuracy, relative risk (RR) and their 95% confidence intervals (CIs) were calculated. Twenty-five studies including 17 full texts and eight meeting abstracts were included for analysis. Compared to WLC, pooled ADR of NBI for NMIBC diagnosis was 9.9% (95% CI: 0.05-0.14) and 18.6% (95% CI: 0.15-0.25) in per-patient and per-lesion analysis, respectively. Pooled ADR of NBI for carcinoma in situ (CIS) diagnosis was 25.1% (95% CI: 0.09-0.42) and 31.1% (95% CI: 0.24-0.39) for per-patient and per-lesion analyses, respectively. The pooled sensitivity of NBI was significantly higher than WLC both at the per-patient (95.8% vs. 81.6%) and per-lesion levels (94.8% vs. 72.4%). In addition, NBI significantly reduced the recurrence rate of bladder cancer with a pooled RR value of 0.43 (95% CI: 0.23-0.79) and0.81 (95% CI: 0.69-0.95) at month three and twelve, respectively. NBI is a valid technique that improves the diagnosis of NMIBC and CIS compared to standard WLC either at per-patient or per-lesion level. It can reduce the recurrence rate of bladder cancer accordingly.