Estrogen reduction by aromatase inhibition for benign prostatic hyperplasia: results of a double-blind, placebo-controlled, randomized clinical trial using two doses of the aromatase-inhibitor atamestane. Atamestane Study Group.

BACKGROUND: The concept of estrogen withdrawal by an aromatase inhibitor in the treatment of benign prostatic hyperplasia (BPH) was assessed in a prospective, randomized, double-blind, placebo-controlled multicenter trial. METHODS: Two hundred and ninety-two patients with clinical symptoms of BPH were randomly allocated to one of the following treatments for 48 weeks: placebo or the selective aromatase inhibitor, atamestane, at a daily dose of 100 mg or 300 mg. Both doses of atamestane significantly reduced serum concentrations of estradiol and estrone, and produced a slight, dose-dependent, counter-regulatory increase in peripheral androgen concentration. RESULTS: Clinical symptoms improved during treatment in all three groups. Even after 48 weeks, the effect of active treatment did not exceed the effect seen with placebo. Overall tolerance of 100 mg atamestane was excellent, but 300 mg showed a slightly increased incidence of side effects compared with placebo. CONCLUSIONS: The conclusion from this study is that the reduction in estrogen concentration using the selective aromatase inhibitor atamestane has no effect on clinically established BPH.