5-α Reductase Inhibitors and Risk of Overall and Lethal Bladder Cancer

Abstract

Abstract Purpose: To determine if an association exists between 5-α Reductase Inhibitor (5-ARI) use and the risk of overall bladder cancer or lethal bladder cancer. Materials and Methods: This prospective cohort study included 39,427 men in the United States who were part of the Harvard School of Public Health’s Health Professionals Follow-up Study. We identified men who did not carry a diagnosis of cancer (other than non-melanoma skin cancer) in 1996 and prospectively followed them for 5-ARI use, cancer incidence, metastases, and mortality until 2012 using biannual questionnaires and, beginning in 2000, an annual bladder cancer specific cancer survey for men carrying that diagnosis. The primary exposure variable was 5-ARI use Results: Over the course of 16 years (595,377 person-years) of follow-up, there were 943 diagnosed cases of bladder cancer, of which 159 were cases of lethal bladder cancer. Ever use of 5-ARIs was reported by 4105 men (10.4%) between 1996 and 2012. No association with 5-ARI ever use and bladder cancer was detected in either our age-adjusted model (HR 1.24, 95% CI 0.98-1.56) or in our multivariate analysis (HR 1.15, 95% CI 0.91-1.46, p=.25). Similarly, no significantly changed risk was of bladder cancer was detected when an analysis was conducted examining duration of 5-ARI exposure. Conclusions: There was no statistically significant relationship between 5-ARI usage, ever vs. never or duration of use, and the development of overall or lethal bladder cancer in either age adjusted or fully adjusted models.