5-alpha reductase inhibitors (5-ARi) with or without alpha-blockers (α-B) for Benign Prostatic Hyperplasia do NOT lower the risk of incident Bladder Cancer: United States insurance claims data

Background: Chemoprotective effect of 5-alpha reductase inhibitors (5-ARi) on bladder cancer (BCa) risk in men with Benign Prostatic Hyperplasia (BPH) has been explored with conflicting results. We sought to examine the effect of 5-ARi on new BCa diagnoses in a large US database. Methods: Men ≥ 50 y/o with a prescription for 5-ARi after BPH diagnosis were identified in the IBM® Marketscan® Research de-identified Databases between 2007 and 2016 and matched with paired controls. Incident BCa diagnoses were identified after BPH diagnosis and/or pharmacologic treatment. Multivariable regression modeling adjusting for relevant factors was implemented. Sub-group analyses by exposure risk were performed to explore the association between 5-ARi and BCa over time. Administration of alpha-blockers (α-B) w/o 5-ARi was also examined. Results: In total, n = 24,036 men on 5-ARi, n = 107,086 on 5-ARi plus alpha-blockers, and n = 894,275 without medical therapy for BPH were identified. The percentage of men diagnosed with BCa was 0.8% for the 5-ARi, 1.4% for the 5-ARi + α-B, and 0.6% for the untreated BPH group of incident BCa (adjusted hazard ratio [aHR], 0.90, 95% confidence interval [CI] 0.56 - 1.47), and 1.08, 95%CI 0.89 - 1.30, respectively). This was also true at both shorter (≤ 2 yr) and longer-term (> 2 yr) follow up. In addition, α-B alone had no change in BCa risk (HR 1.06, 0.86-1.30). Conclusions: We did not find any diminished risk of new BCa in men treated with 5-ARi (i.e., chemoprotective effect). The current report suggests that 5-ARi do not change a man's bladder cancer risk.