The results of an 18-year study, just published in the New England Journal of Medicine, showed that finasteride does not increase the likelihood of death from prostate cancer in men who take the drug. Early results from the same study had suggested that finasteride might increase the risk of developing higher grade tumors; however, follow-up results from the long-term study show that men taking the drug do not have an increased risk.
Additionally, the results of the study show that taking finasteride actually decreases the likelihood of a diagnosis of prostate cancer in men by 30% and a diagnosis of “low-grade” cancer in men by 43%. By shrinking the healthy prostate tissue, finasteride decreases the chances of a false positive result in PSA screening tests and can avoid unnecessary surgery.
From the article in the NEJM:
“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.”
Read a summary of the NEJM article below:
Long-Term Survival of Participants in the Prostate Cancer Prevention Trial
Ian M. Thompson, Jr., M.D., Phyllis J. Goodman, M.S., Catherine M. Tangen, Dr.P.H., Howard L. Parnes, M.D., Lori M. Minasian, M.D., Paul A. Godley, M.D., Ph.D., M. Scott Lucia, M.D., and Leslie G. Ford, M.D.
N Engl J Med 2013; 369:603-610 August 15, 2013
BACKGROUND
In the Prostate Cancer Prevention Trial (PCPT), finasteride significantly reduced the risk of prostate cancer but was associated with an increased risk of high-grade disease. With up to 18 years of follow-up, we analyzed rates of survival among all study participants and among those with prostate cancer.
METHODS
We collected data on the incidence of prostate cancer among PCPT participants for an additional year after our first report was published in 2003 and searched the Social Security Death Index to assess survival status through October 31, 2011.
RESULTS
Among 18,880 eligible men who underwent randomization, prostate cancer was diagnosed in 989 of 9423 (10.5%) in the finasteride group and 1412 of 9457 (14.9%) in the placebo group (relative risk in the finasteride group, 0.70; 95% confidence interval [CI], 0.65 to 0.76; P<0.001). Of the men who were evaluated, 333 (3.5%) in the finasteride group and 286 (3.0%) in the placebo group had high-grade cancer (Gleason score, 7 to 10) (relative risk, 1.17; 95% CI, 1.00 to 1.37; P=0.05). Of the men who died, 2538 were in the finasteride group and 2496 were in the placebo group, for 15-year survival rates of 78.0% and 78.2%, respectively. The unadjusted hazard ratio for death in the finasteride group was 1.02 (95% CI, 0.97 to 1.08; P=0.46). Ten-year survival rates were 83.0% in the finasteride group and 80.9% in the placebo group for men with low-grade prostate cancer and 73.0% and 73.6%, respectively, for those with high-grade prostate cancer.
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.
Posted by Robert M. Bernstein M.D. 
