Purpose: To evaluate the diagnostic accuracy of a second look narrow-band imaging (NBI) cystoscopy in the follow-up of patients with NMIBC as compared to a second white light cystoscopy (WLI).
Patients and methods: From August 2013 to October 2014, 600 patients with history of non-muscle invasive bladder cancer (NMIBC), who presented for follow-up cystoscopy at an academic outpatient clinic, were randomized to flexible WLI-cystoscopy plus second look NBI-cystoscopy (n = 300) or flexible WLI-cystoscopy plus second look WLI-cystoscopy (n = 300) in the same session. We analysed the detection rate of bladder tumours in second look cystoscopy as primary endpoint. In addition, we evaluated recurrence rates before study enrolment and after transurethral resection (TUR-BT) in each group.
Results: In 600 patients with a history of NMIBC, 78 out of 300 patients (26%) with WLI-NBI-cystoscopy and 70 out of 300 patients (23%) with WLI-WLI-cystoscopy were diagnosed with cancer recurrence (p = 0.507). Overall, WLI-NBI detected 404 and WLI-WLI 234 lesions, respectively. The second look cystoscopy detected 57 additional cancer lesions: 45 tumours in 18 patients with WLI-NBI and 12 tumours in 9 patients with WLI-WLI (p = 0.035). After initial examination without tumour detection an improvement was determined by the second cystoscopy in 3 patients (75 vs. 78 pat.) with WLI-NBI and in only one patient (69 vs. 70 pat.) with WLI-WLI (p = 0.137). Second look cystoscopy did not influence the detection of carcinoma in situ in both groups (p = 0.120). After TUR-BT the median recurrence-free survival was 4 months in 57 recurring patients (73%) in the group with WLI-NBI- and 6 months in 56 patients (80%) with WLI-WLI-cystoscopy (p = 0.373), respectively.
Conclusion: Our study showed no differences in per-patient tumour detection between WLI and NBI. Although NBI has significant benefits for detecting individual lesions overlooked by WLI-cystoscopy, this did not positively affect recurrence-free survival after transurethral resection.
Keywords: Bladder tumours; Narrow-band cystoscopy; Transurethral resection.