Men who take Avodart (dutasteride) to treat an enlarged prostate apparently have a reduced risk for developing prostate cancer, a new study indicates.

Avodart and a similar drug, Propecia (finasteride), are technically classified as 5-alpha-reductase inhibitors. They suppress the potent male hormone dihydrotestosterone and thereby inhibit growth of the prostate in men with benign prostatic hyperplasia, commonly known as BPH.

Dr. Gerald L. Andriole from Washington University School of Medicine in St. Louis, Missouri, and colleagues used data from three recently completed trials to investigate whether dutasteride treatment, in comparison to treatment with an inactive placebo, had a meaningful effect on the rate of prostate cancer detection.

The cumulative rate of prostate cancer detected during the first 24 months of dutasteride treatment was 1.1 percent, compared with 1.9 percent in patients treated with placebo, the researchers report in the medical journal Urology.

Additional cancers reported between month 24 and month 27 slightly changed the cumulative incidence rates (1.2 percent for dutasteride, 2.5 percent for placebo), resulting in a 51 percent lower risk of prostate cancer for the dutasteride group relative to the placebo group.

Referring to another study, Andriole told Reuters Health: “The results from the Prostate Cancer Prevention Trial (PCPT), which shows that finasteride reduces the incidence of prostate cancer, strongly suggest that 5-alpha-reductase inhibition will play a key role in the reduction in risk of prostate cancer development and progression.”

Based on these findings, the investigators write, a trial “has been designed to establish further the efficacy of dutasteride” for the prevention of prostate cancer.

“We anticipate complete enrollment of the trial by the spring of 2005,” Andriole said, “and results should be available after participating men complete 4 years of treatment and their end-of-study biopsies.”

SOURCE: Urology, September 2004.