Neil E. Fleshner, MD, MPH, of the University of Toronto, and colleagues conducted a randomized, double-blind, placebo-controlled study to investigate the safety and efficacy of dutasteride, a 5α-reductase inhibitor, for men with low-risk prostate cancer.
Participants with low-volume, Gleason score 5 to 6 prostate cancer, who chose to be followed with active surveillance, were enrolled and randomly allocated to receive once-daily dutasteride (144 men) or matching placebo (145 men). The time to prostate cancer progression was the primary endpoint.
The researchers found that, by three years, significantly fewer men in the dutasteride group (38%) had pathologic or therapeutic prostate cancer progression compared with those in the control group (48%), which translated into a 38% decreased risk of progression in the dutasteride recipients, according to a report published online in The Lancet.
The adverse event incidence was similar between the groups. Researchers observed sexual adverse events, breast enlargement, or breast tenderness in 24% of the dutasteride group and 15% of controls, and 5% of subjects in each group had cardiovascular adverse events. The investigators observed no prostate cancer-related deaths or cases of metastatic disease.
“Findings from our study show that dutasteride could be a beneficial adjunct to active surveillance for men with low-risk prostate cancer, delaying their time to pathological progression and initiation of primary therapy,” the authors wrote.