Surveillance of non-muscle-invasive bladder cancer with blue-light cystoscopy: a meta-analysis

Objective: To compare the value of flexible blue-light cystoscopy (BLC) vs flexible white-light cystoscopy (WLC) in the surveillance setting of non-muscle-invasive bladder cancer (NMIBC). Methods: All major databases were searched for articles published before May 2023 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The primary outcome was the accuracy of flexible BLC vs WLC in detecting bladder cancer recurrence among suspicious bladder lesions. Results: A total of 10 articles, comprising 1634 patients, were deemed eligible for the quantitative synthesis. In the meta-analysis focusing on the detection of disease recurrence, there was no difference between flexible BLC and WLC (odds ratio [OR] 1.08, 95% confidence interval [CI] 0.82–1.41)]; the risk difference (RD) showed 1% of flexible BLC, corresponding to a number needed to treat (NNT) of 100. In the subgroup meta-analysis of detection of carcinoma in situ (CIS) only, there was again no significant difference between flexible BLC and WLC (OR 1.19, 95% CI 0.82–1.69), BLC was associated with a RD of 2% (NNT = 50). The positive predictive values for flexible BLC and WLC in detecting all types of recurrence were 72% and 66%, respectively, and for CIS they were 39% and 29%, respectively. Conclusion: Surveillance of NMIBC with flexible BLC could detect more suspicious lesions and consequently more tumour recurrences compared to flexible WLC, with a increase in the rate of false positives leading to overtreatment. A total of 100 and 50 flexible BLC procedures would need to be performed to find on additional tumor and CIS recurences, respectively. A risk-stratified strategy for patient selection could be considered when using flexible BLC for the surveillance of NMIBC patients.