J. Kellogg Parsons, MD, of the University of California in San Diego, and colleagues made the discovery after performing a secondary analysis of data from the Prostate Cancer Prevention Trial (PCPT). In the trial, investigators randomized men to receive finasteride 5 mg per day or placebo. Results showed that finasteride decreased the risk of prostate cancer by about 25%.
The secondary analysis focused on 9,253 men. After a mean follow-up of 5.3 years, the rate of clinical BPH was 11 per 1000 person-years in the finasteride arm compared with 19 per 1000 person-years in the placebo arm, a significant difference that translated into a 40% decreased risk of clinical BPH associated with finasteride use, the researchers reported online ahead of print in European Urology. Finasteride reduced the risk by 44% among men aged 65 or older.
The effect of the finasteride, which is a 5α-reductase inhibitor (5-ARI), on clinical BPH did not differ significantly by age, race, diabetes status, current smoking, or physical activity.
“These data provide the first clinical evidence that BPH may be prevented and directly inform the ongoing scientific and health policy dialogue with respect to the use of 5-ARIs for the chemoprevention of prostate cancer,” the authors wrote.
The investigators defined clinical BPH as the initiation of medical treatment, surgery, or sustained, clinically significant urinary symptoms (International Prostate Symptom Score of 8 or higher).
Dr. Parsons and his colleagues calculated that the number of men that needed to be treated with finasteride to prevent one case of clinical BPH over seven years was 58 for men aged 55-59; 42 for men aged 60-64; and 31 for men aged 65 or older.