A comparison of NBI and WLI cystoscopy in detecting non-muscle-invasive bladder cancer: A prospective, randomized and multi-center study

Several single-center studies have investigated whether narrow-band imaging (NBI) cystoscopy is more effective in detecting primary and recurrent non-muscle invasive bladder cancer (NMIBC) compared with white-light imaging (WLI) cystoscopy. In this study, we further evaluated the diagnostic value of NBI cystoscopy compared with WLI cystoscopy for primary NMIBC in a multi-center study. Suspected bladder cancer patients from 8 research centers received both NBI and WLI. Two experienced doctors in each center were responsible for the NBI and WLI assessments, respectively. The number of tumors and position of each tumor were recorded and suspicious tissues were clamped and histologically examined. The sensitivity, specificity and false-positive rate of NBI and WLI were evaluated. Of the 384 patients, 78 had a confirmed urothelial carcinoma (UC). The sensitivities of NBI and WLI were 97.70% and 66.67%, respectively ( P < 0.0001); the specificities were 50% and 25%, respectively; and the false positive rates were 50% and 75%, respectively. Based on 300 valid biopsy specimens, the NBI and WLI sensitivities were 98.80% and 75.45%, respectively ( P < 0.0001). These results suggest that NBI has a high sensitivity and has superior early bladder tumor and carcinoma in situ (CIS) detection rates compared with WLI cystoscopy.