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

ABSTRACT

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.