5α-Reductase Inhibitors and Risk of Kidney and Bladder Cancers in Men with Benign Prostatic Hyperplasia: A Population-Based Cohort Study

Background: Preclinical evidence suggests that 5a-reductase inhibitors (5ARi), commonly used to treat benign prostatic hyperplasia (BPH), are associated with reduced incidence of certain urologic cancers, yet epidemiologic studies are conflicting. This study aimed to determine whether 5ARi’s are associated with a reduced risk of kidney and bladder cancers.
Methods: We conducted a new-user active-comparator cohort study in the United Kingdom Clinical Practice Research Datalink. From a base cohort of patients with incident BPH, new users of 5ARi’s and a-blockers were identified. Patients were followed up until a first ever diagnosis of kidney or bladder cancer, death from any cause, end of registration, or December 31, 2017. Cox proportional hazards models were used to calculate HRs and 95% confidence intervals (CI) for incident kidney and bladder cancer.
Results: There were 5,414 and 37,681 new users of 5ARi’s and a-blockers, respectively. During a mean follow-up of 6.3 years, we found no association between the use of 5ARi’s and kidney (adjusted HR, 1.26; 95% CI,0.74–2.12; n = 23) or bladder (adjusted HR, 0.89; 95% CI, 0.64–1.23; n = 57) cancer risk compared with a-blockers. Similar results were observed across sensitivity analyses.
Conclusions: In this study, we found no association between the use of 5ARi’s and kidney or bladder cancer incidence in men with BPH when compared with a-blocker use. Impact: The findings of this study indicate that 5ARi’s are unlikely to reduce kidney or bladder cancer risk.