NEW YORK (Reuters Health) – Finasteride reduces clinical progression of benign prostatic hyperplasia (BPH) over the long term in men with prostate volumes of 30 mL or greater, according to a post hoc analysis of data from the Medical Therapy of Prostatic Symptoms (MTOPS) trial published in the February 22nd online issue of The Journal of Urology.

The beneficial effects of finasteride on urinary symptoms and BPH outcomes are generally believed to be restricted to men with an enlarged prostate, and the drug is approved for the treatment of BPH symptoms in men with an enlarged prostate.

Dr. Steven A. Kaplan from Weill Cornell Medical College, New York and colleagues in the MTOPS research group used data from 1140 men from the finasteride and placebo treatment groups of MTOPS to assess the long-term effects of finasteride on urinary symptoms and clinical progression in the subgroups of men with a baseline prostate volume of less than 30 mL (smaller prostate) and those with a baseline prostate volume of 30 mL or more (enlarged prostate).

The mean decrease in symptom score from baseline was significantly higher with finasteride than with placebo in the enlarged prostate group, but not in the smaller prostate group in the intent-to-treat analysis.

In the per-protocol analysis, the differences between finasteride and placebo were significant for both prostate volume cohorts.

Finasteride treatment led to significant increases in maximum urinary flow only in the group of men with enlarged prostate, whereas postvoid residuals did not change significantly with finasteride treatment in either prostate volume group.

In both prostate volume groups, treatment with finasteride resulted in significant improvements in prostate volume relative to placebo treatment from baseline to study end.

Only in the enlarged prostate group, however, did treatment with finasteride lead to a significant increase relative to placebo in the cumulative percentage of men who did not meet the criteria for clinical progression of BPH.

“Given the significantly lower rate of clinical progression of BPH observed in men with prostate volume 30 mL or greater who were treated with finasteride compared to placebo,” the researchers conclude, “patients with symptomatic BPH with an enlarged prostate and their treating physicians should consider the benefits observed in this study from treatment with finasteride when determining treatment choice.”

The Journal of Urology 2011;185:1369-1373.