Long-term effects of finasteride in patients with benign prostatic hyperplasia: a double-blind, placebo-controlled, multicenter study. PROWESS Study Group

OBJECTIVES: To compare the long-term effects of finasteride (5 mg/day) and placebo in patients with moderate symptoms of benign prostatic hyperplasia (BPH). METHODS: Patients aged 50 to 75 years, with at least two urinary symptoms indicating moderate BPH, and an enlarged prostate, were followed in a 2-year double-blind, randomized, placebo-controlled multicenter study. The effects of finasteride versus placebo were assessed by total symptom score (modified Boyarsky), obstructive symptom score, maximal urinary flow rate, prostate volume, and urologic end points (acute urinary retention, BPH-related surgical intervention). RESULTS: Of the 3270 men enrolled, 3168 contributed data to the safety analysis, and 2902 to the efficacy evaluation. Significantly greater improvement with finasteride compared to placebo was observed at 12 and 24 months for total symptom score (mean -2.9 versus -1.9 at 12 months, P < or =0.001; -3.2 versus -1.5 at 24 months, P < or =0.001), obstructive symptom score (mean -1.9 versus -1.3 at 12 months, P < or =0.001; -2.1 versus -1.1 at 24 months, P < or =0.001), maximal urinary flow rate (mean +1.2 versus +0.6 mL/s at 12 months, P = 0.010; +1.5 versus +0.7 mL/s at 24 months, P = 0.002), and prostate volume (mean -14.2 versus +5.4% at 12 months, P < or =0.01; -15.3 versus +8.9% at 24 months, P < or =0.001). Greater improvements in placebo-adjusted total symptom score occurred in men with large prostates than in men with small prostates (mean -2.4 versus -1.1 at 12 months; -3.2 versus -1.3 at 24 months, placebo-adjusted data, P = 0.053). Fifteen of 1450 men (1.0%) in the finasteride group experienced an acute urinary retention event, compared with 37 of 1452 (2.5%) in the placebo group, and the corresponding figures for surgery were 51 of 1450 (3.5%) and 86 of 1452 (5.9%), respectively. The hazard rate for occurrence, computed using the log-rank statistic, decreased by 57% for acute urinary retention and by 40% for surgery accompanied by finasteride therapy compared to placebo. CONCLUSIONS: Finasteride causes long-term symptomatic improvement and reduces the risk of acute urinary retention or surgery. Men with enlarged prostates benefit most from finasteride treatment.