"Long-Term Survival of Participants in the Prostate Cancer Prevention Trial"
NEJM Aug
http://www.nejm.org/doi/full/10.1056/NEJMoa1215932 
"CONCLUSIONS

Finasteride reduced the risk of prostate cancer by about one third. High-grade prostate cancer was more common in the finasteride group than in the placebo group, but after 18 years of follow-up, there was no significant between-group difference in the rates of overall survival or survival after the diagnosis of prostate cancer. (Funded by the National Cancer Institute.)"