PROSTATE TISSUE COMPOSITION AND RESPONSE TO FINASTERIDE IN MEN WITH SYMPTOMATIC BENIGN PROSTATIC HYPERPLASIA

Purpose: We sought to quantify prostate tissue changes induced by fina steride and to identify a predictor of finasteride response in men wit h symptomatic benign prostatic hyperplasia (BPH) via a randomized, pla cebo controlled, double-blind clinical trial. Materials and Methods: M en with symptomatic BPH (52 to 78 years old) were randomly assigned to 6 months of treatment with finasteride (26) or placebo (15). Outcome measures were clinical (urinary symptom score and flow rate), chemical (serum prostate specific antigen and dihydrotestosterone levels), vol umetric (transrectal ultrasound, and magnetic resonance imaging for wh ole and zonal prostate volumes) and histological (morphometry of prost ate sextant biopsies, separated into inner and outer gland segments, t o measure the percent epithelium, stroma and glandular lumen). Results : In the finasteride group we found a suggestion of decreasing symptom scores and increasing flow rates (not significant) with significant d ecreases (p<0.01) in prostate specific antigen (48%), dihydrotestoster one (74%) and prostate volume (21%). Finasteride treatment induced a 5 5% decrease in inner gland epithelium (p<0.01) with little effect on s troma or lumina. We also found a linear correlation between pretreatme nt inner gland epithelial content and prostate volume decrease induced by the drug (tau = 0.58, p=0.01). Conclusions: Finasteride treatment results in a major suppression of prostate epithelium, which is most p ronounced in the inner gland. Moreover, a finasteride induced prostate volume decrease was predictable by quantification of epithelial tissu es of the inner gland. These data lend additional support to the emerg ing concept of transition zone primacy in symptomatic BPH.