Dutasteride shown to reduce the risk of prostate cancer by 23 percent

Researchers from the Washington University School of Medicine in St. Louis presented their findings from the REDUCE - Reduction by Dutasteride of Prostate Cancer Events - trial to members of the American Urological Association (AUA) meeting in Chicago. The trial, which was conducted at 250 sites in 42 countries around the world, involved 8,200 men, ranging from 50 to 75. All of the participants had elevated PSA levels in the 2.5 - 10 ng/ml range, putting them at increased risk for prostate cancer. There was no evidence of any cancer in study participants prior to enrolling in the trial, suggesting that they either did not have cancer or their tumors were too small to be detected by the study pre-biopsy.

Each participant was randomly assigned to receive either a placebo or a daily 0.5 mg dose of dutasteride. Scheduled biopsies were performed after two years, then again after four years. The researchers found that of those men who took the placebo, prostate cancer was found in 17.2 percent, and just 13.4 percent in those given dutasteride. The difference was even more significant after four years: another 11.8 percent of men who received a placebo were diagnosed with prostate cancer, compared to just 9.1 percent who received dutasteride.

"In these men, the most likely explanation is that dutasteride worked by shrinking tumors and/or slowing their growth, thereby making them less likely to be detected by a biopsy," says Lead Investigator Gerald Andriole, M.D. "This drug has the potential to offer many thousands of men a way to reduce their risk of being diagnosed with prostate cancer and, as a result, more men could avoid treatment for prostate cancer and the cost and unwanted side effects associated with treatment," he adds.

Despite an earlier trial showing that a similar drug (finasteride) may have produced more aggressive tumors in men who had developed prostate cancer while on the drug, the researchers did not find any greater risk in those men who did develop prostate cancer to have aggressive tumors. In fact, the results were essentially the same: 6.8 percent of men in the placebo group were found to have aggressive, high-grade tumors compared to 6.7 percent of men in the dutasteride group. "We are very encouraged by this finding," Dr. Andriole says. "Clearly, the data show dutasteride did not lead to more high-grade tumors, even though they would have been easier to detect in the dutasteride-treated men due to their smaller prostates," he adds.

News Release: Data show dutasteride reduces prostate cancer diagnosis in men with increased risk    www.newswise.com  April 28, 2009