Clinical experience of the detection of prostate cancer in patients with benign prostatic hyperplasia treated with finasteride

The clinical experience relating to the detection of prostate cancer in patients participating in 2 large multicenter clinical trials of finasteride in the treatment of benign prostatic hyperplasia is reviewed. A total of 1,645 patients 40 to 83 years old with benign prostatic hyperplasia was randomized to receive 1 or 5 mg. finasteride or placebo once a day for 12 months in a double-blind fashion followed by an open extension study in which all patients were treated with 5 mg. finasteride daily. At entry, all patients were to have a maximum urinary flow rate of 15 ml. per second or less with a voided volume of 150 ml. or more, an enlarged prostate and symptoms of urinary obstruction. Patients with a prostate specific antigen level of 40 ng./ml. or more, or any finding suggestive of prostate cancer were excluded. During the study period 32 cases of prostate cancer were diagnosed: 12 were detected during the 12 months of the controlled study and were evenly distributed among the treatment groups (4 on placebo, and 3 on 1 mg. and 5 on 5 mg. finasteride) and 20 cases were detected in the extension study. From these results we conclude that finasteride-treated patients should be evaluated periodically by digital rectal examination, careful monitoring of prostate specific antigen levels and appropriate investigation of any suspicious findings.