A drug commonly used to treat enlarged prostates may also slow the growth of prostate cancer tumors, a new study has found.
Canadian researchers said their findings indicate dutasteride -- sold as Avodart – could be used to treat men with early-stage prostate cancer and reduce their need for debilitating treatments that sometimes cause impotence and incontinence.
As many as one in six men are diagnosed with prostate cancer, but most have non-aggressive tumors that are slow-growing and not life-threatening. For these men, doctors often recommend “watchful waiting” - monitoring the disease closely – instead of aggressive surgery, radiation or chemotherapy.
The new research suggests Avodart might be an additional option for men with low-risk prostate cancer.
“Our trial is the first study to show the benefits of [Avodart] to reduce the need for aggressive treatment in men undergoing active surveillance for low-risk prostate cancer…delaying their time to pathological progression and initiation of primary therapy,” said Neil Fleshner from Princess Margaret Hospital, Toronto, lead author of the study, published in The Lancet.

Fleshner’s study involved 302 low-risk prostate cancer patients -- aged 48 to 82 years. Half were given the drug, the others received a dummy pill. The men then underwent biopsies at 18 months and three years to measure their disease progression.
Researchers found men given the drug were “significantly” less likely to experience a progression in the cancer than those who did not. About 48 percent who were given the placebo experienced disease progression, compared to just 38 percent of the men receiving the drug.
In addition, men treated with Avodart were more likely to have no cancer detected in their final biopsy. In 50 of the men, doctors could find no cancer at all.
In an accompanying commentary, Chris Parker from the Royal Marsden National Health Service Foundation Trust, noted the study does not address more aggressive forms of prostate cancer.
“These data are consistent with the hypothesis that dutasteride reduces the volume of low-grade prostate cancers but has no effect, or even an adverse effect, on the progression of high-grade disease,” Parker wrote. “Thus, although reducing overall prostate cancer detection, dutasteride could plausibly have no effect (or possibly a deleterious one) on prostate cancer mortality.”