Monopolar versus bipolar transurethral resection of bladder Tumour: post-hoc analysis of a prospective trial

Introduction Previously, in a randomised trial we demonstrated bipolar transurethral resection of bladder tumor (TURBT) could achieve a higher detrusor sampling rate than monopolar TURBT. We hereby report the long-term oncological outcomes following study intervention. Methods This is a post-hoc analysis of a randomized phase III trial comparing monopolar and bipolar TURBT. Only patients with pathology of non-muscle invasive bladder cancer (NMIBC) were included in the analysis. Per-patient analysis was performed. Primary outcome was recurrence-free survival (RFS). Secondary outcomes included progression-free survival (PFS), cancer-specific survival (CSS) and overall survival (OS). Results From the initial trial, 160 cases were randomised to receive monopolar or bipolar TURBT. 24 cases of non-urothelial carcinoma, 22 cases of muscle-invasive bladder cancer, and 9 cases of recurrences were excluded. A total of 97 patients were included in the analysis, with 46 in the monopolar and 51 in the bipolar group. The median follow-up was 97.1 months. Loss-to-follow-up rate was 7.2%. Regarding the primary outcome of RFS, there was no significant difference (HR = 0.731; 95%CI = 0.433–1.236; P = 0.242) between the two groups. PFS (HR = 1.014; 95%CI = 0.511–2.012; P = 0.969), CSS (HR = 0.718; 95%CI = 0.219–2.352; P = 0.584) and OS (HR = 1.135; 95%CI = 0.564–2.283; P = 0.722) were also similar between the two groups. Multifocal tumours were the only factor that was associated with worse RFS. Conclusion Despite the superiority in detrusor sampling rate, bipolar TURBT was unable to confer long-term oncological benefits over monopolar TURBT.