Purpose: We determined the effect of long-term treatment with finasteride on the incidence of acute urinary retention (AUR) and benign prostatic hyperplasia (BPH) related surgery in men with BPH.
Materials and methods: The Proscar (Merck and Co., Inc., Whitehouse Station, New Jersey) Long-Term Efficacy and Safety Study (PLESS) was comprised of 3040 men with enlarged prostates, moderate to severe symptomatic BPH and no clinical evidence of prostate cancer. Patients were randomized to placebo or 5 mg finasteride daily for 4 years. Of the 3016 randomized patients with available efficacy data 62% completed the original 4-year study (1006 on finasteride and 891 on placebo) and 89% of these (908 from the original finasteride arm and 785 from the placebo arm) continued in a 2-year open extension on finasteride. Followup was attempted in discontinued patients. Complete 6-year outcomes data, including 6-year followup in 770 men who had discontinued treatment during years 1 to 6, were available for 2463 (82%) of the 3016 originally randomized patients.
Results: For patients on continuous finasteride treatment the decrease in incidence of AUR and/or BPH related surgery in the 4-year base study was sustained during the open extension. In patients who were switched from placebo to finasteride in the extension, the incidence of AUR and/or BPH related surgery was similar to that in the continuous finasteride arm.
Conclusions: The 6-year data from PLESS confirmed and further extended the findings from the original 4-year trial, demonstrating that finasteride treatment led to a sustained decrease in the incidence of AUR and/or BPH related surgery in men with BPH and enlarged prostates.