5α-reductase inhibitors with or without alpha-blockers and risk of incident upper tract urothelial carcinoma in men with benign prostatic hyperplasia: Analysis of US insurance claims data

Background: Increasing data suggests that androgen receptor signaling may play an important role in the carcinogenesis of urothelial cancers. While the chemoprotective effect of 5-alpha reductase inhibitors (5-ARi) on bladder cancer risk in men with Benign Prostatic Hyperplasia (BPH) has been explored with conflicting results, the evidence regarding 5-ARi treatment, and the risk of incident Upper Tract Urothelial Carcinoma (UTUC) development is lacking. Therefore, our objective was to investigate the impact of the 5-ARi administration on the incidence of new UTUC cases using a large US database. Methods: The MerativeTM Marketscan® database was used to identify men ≥ 50 years old with a diagnosis of BPH and an active 5-ARi prescription between 2007 and 2021 and were subsequently matched with paired controls. A multivariable Cox regression model was implemented to ascertain the association of 5-ARi and/or alpha-blocker (α-B) medications on the incidence of UTUC. Additional subgroup analyses were conducted based on exposure risk (with a 2-year threshold) to investigate the relationship between 5-ARi and UTUC over time. Results: Overall, n=1,103,743 men BPH without prescriptions for BPH, n=31,142 men on 5-ARi, and n=160,049 using 5-ARi + α-B were identified. Over the follow-up period, a total of n=4,761 patients were diagnosed with UTUC. After matching, UTUC incidence ranged from 0.36% to 0.41% in men without active BPH therapy vs. 0.30% and 0.52% for the 5-ARi and 5-ARi + α-B groups, respectively. In multivariable analysis, the chemoprotective effect on UTUC risk was not observed for either 5-ARi monotherapy (adjusted hazard ratio [aHR]: 0.91, 95% CI: 0.58–1.44) or 5-ARi + α-B combination (aHR: 1.02, 95% CI: 0.87–1.19). This remained true for both short-term (≤ 2 years) and long-term (> 2 years) follow-up periods. Conclusions: The use of 5-ARi for BPH, whether used alone or in combination with α-B, is not associated with incident UTUC.