The Long-Term Impact of 5-alpha Reductase Inhibitors on the Development of Bladder Cancer and the Need for Radical Cystectomy: A Nationwide Observational Study

Purpose: To investigate the long-term effects of taking 5-alpha reductase inhibitors (5ARIs) on the development of bladder cancer (BC) and the implementation of radical cystectomy (RC), a standard procedure for advanced BC. Materials and Methods: From the National Health Insurance Sharing Service database, males aged over 40 years who underwent serum prostate-specific antigen testing from 2006 through 2017 were identified, which is required for the prescription of 5ARIs. The association between the administration duration of 5ARIs and the practice for BC was analyzed. Results: Of the 3,843,968 subjects, 1,514,713 (39.4%) took 5ARIs for an average of 1.53 years, remaining 2,329,255 (60.6%) as non-5ARI counterparts. The incidence of BC was higher in the non-5ARI than in the 5ARI group (1.25% vs. 0.87%, p