Photodynamic Diagnosis-Assisted Transurethral Resection Using Oral 5-Aminolevulinic Acid Decreases the Risk of Repeated Recurrence in Non-Muscle-Invasive Bladder Cancer: A Cumulative Incidence Analysis by the Person-Time Method

Clinical evidence regarding risk reduction of repeated bladder recurrence after initial photodynamic diagnosis (PDD)-assisted transurethral resection of bladder tumor (TURBT) is still limited in patients with non-muscle-invasive bladder cancer (NMIBC). We analyzed patients with primary NMIBC undergoing TURBT without any adjuvant treatment to compare the risk of cumulative recurrence between the conventional white-light (WL)-TURBT and PDD-TURBT. Out of 430 patients diagnosed with primary NMIBC from 2010 to 2019, 40 undergoing WL-TURBT and 60 undergoing PDD-TURBT were eligible. Multivariate Cox regression analysis for time to the first recurrence demonstrated that PDD assistance was an independent prognostic factor with better outcome (p = 0.038, hazard ratio = 0.39, and 95% confidence interval 0.16-0.95). While no patient experienced more than one recurrence within 1000 postoperative days in the PDD-TURBT group, five out of 40 patients treated by WL-TURBT experienced repeated recurrence. The comparison of cumulative incidence per 10,000 person-days between the two groups revealed that PDD assistance decreased by 6.6 recurrences per 10,000 person-days (exact p = 0.011; incidence rate ratio 0.37, Clopper-Pearson confidence interval 0.15-0.82). This is the first study addressing PDD assistance-induced risk reduction of repeated bladder recurrence using the person-time method. Our findings could support clinical decision making, especially on adjuvant therapy after TURBT.