A new study has shown that dutasteride, a drug commonly used to treat men with an enlarged prostate gland, may also slow the growth of early-stage prostate cancer among men participating in "active surveillance" of their disease according to researchers at ASCO's fourth annual Genitourinary Cancers Symposium.

"In some cases, we treat prostate cancer that may never become life-threatening. I'm hoping that these results, showing that men may be able to take a drug that slows the cancer's growth, may allow more men to pursue active surveillance for even longer periods," said lead author Neil Fleshner, M.D., Head of Urology at the University Health Network in Toronto, Ontario, Canada, and the Love Chair in Prostate Cancer Prevention at the Princess Margaret Hospital in Toronto.

In the REDEEM (Reduction by Dutasteride of Clinical Progression Events in Expectant Management of Prostate Cancer) study, researchers tested whether the drug dutasteride could control the growth of low-risk, early-stage prostate cancer and further reduce the potential use of more aggressive therapy in men following watchful waiting.

In the study, 302 men with early-stage prostate cancer were randomly given either dutasteride or placebo for three years. Prostate biopsies were taken at 18 and 36 months or if they were warranted because of indications of disease progression. Investigators found that those taking dutasteride had a longer time to cancer progression compared to those taking placebo. In the dutasteride group, 54 of the men (38 percent) experienced some progression of their cancer, compared to 71 (49 percent) of the placebo group. There was a reduced relative risk for cancer progression of 38.9 percent in the dutasteride group.

They also found that those men taking dutasteride had less chance of finding cancer on re-biopsy. Fifty of the men (36 percent) in the drug group and 31 (23 percent) in the placebo group had no cancer detected on their final biopsy. In addition, those who were given dutasteride had lower levels of prostate cancer-related anxiety based on results of a standardized test.

"Even though men realize that if they reach a certain age, many will have some sort of prostate cancer that likely will never give them problems, there is still anxiety associated with monitoring and not treating it," Dr. Fleshner said.