Long-term Consequences of Finasteride vs Placebo in the Prostate Cancer Prevention Trial

Finasteride has been found to reduce the risk of low-grade prostate cancer but to have no impact on overall survival. The long-term adverse and beneficial consequences of finasteride have not been examined.

We used a linkage between data from the Prostate Cancer Prevention Trial (PCPT) and Medicare claims. Patients were examined by randomized study arm (finasteride vs placebo for 7 years) for long-term consequences of the intervention, including cardiac, endocrine, and sexual dysfunction, depression, diabetes, and benign prostatic hyperplasia (BPH)-related events. To examine time to events, we used cumulative incidence and Cox regression, adjusting for covariates. All statistical tests were two-sided.

A total of 13 935 of 18 880 participants (73.8%) in the PCPT were linked to Medicare claims, with median Medicare follow-up assessment time of 16 years from trial registration. There were no differences between finasteride and placebo participants with respect to important baseline factors or amount of Medicare follow-up assessment time. Finasteride patients had a 10% higher risk of new claims for depression (hazard ratio [HR] = 1.10, 95% confidence interval [CI] = 1.01 to 1.19, P = .04) and a 6% lower risk of procedures for BPH-related events (primarily lower urinary tract symptoms; HR = 0.94, 95% CI = 0.89 to 1.00, P = .03). No other differences were found in rates of long-term consequences of intervention in the two study arms.

Finasteride use is associated with reduced need for procedures for relief of BPH-related events and a modest increase in depression. Overall, there is little need to worry about long-term noncancer consequences of finasteride use in those who use it for treatment of symptomatic BPH, hair growth, or prevention of cancer.