ABSTRACTObjectivesTo examine the oncological safety of simultaneous resection of bladder tumor and prostate in the presence of non-muscle invasive high-grade urothelial carcinoma of the bladder (UCB).Materials and MethodsBetween 2007 and 2019, 170 men with high–grade UCB who had a follow-up of at least 12 months were included in the study, including 123 with transurethral resection of bladder tumor (TURBT) only and 47 with simultaneous TURBT and transurethral resection of the prostate (TURP). We recorded and compared patients' clinicopathological parameters, recurrence, and progression rates during the follow–up period, as well as time to UCB recurrence in the bladder and the prostatic urethra/fossa.ResultsBaseline demographic and pathological characteristics were comparable between the groups. At a median follow-up of 31 months in both groups, there were no significant differences in recurrence rates in the bladder and the prostatic urethra/fossa in either group (34.1% and 7.3% vs. 36.2 and 6.4%, p=0.402, p=0.363). No statistically significant differences were found between the two groups in terms of follow-up time, elapsed time to recurrence, or and progression in the bladder or prostatic urethra/fossa.ConclusionsSimultaneous TURBT and TURP in the presence of high-grade UCB appears to be oncologically safe in selected patients.