Dutasteride May Slow Prostate Cancer Progression

Neil Fleshner, MD

Dutasteride, a 5α-reductase inhibitor approved for the treatment of benign prostatic hyperplasia, may postpone disease progression in men with low-risk prostate cancer who have opted for an active surveillance strategy, as well as the need to start primary therapy, new data suggest.

Neil Fleshner, MD, professor of the Department of Surgery at Princess Margaret Hospital in Toronto, Canada, and colleagues elsewhere randomized 302 patients to treatment with once-daily dutasteride 0.5 mg or placebo. The analysis included men ranging from age 48 to 82 years who had low-risk localized prostate cancer and were undergoing active surveillance as part of the joint Canadian-US REduction by Dutasteride of Clinical Progression Events in Expectant Management (REDEEM) trial.

Participants were followed for 3 years, with 12-core prostate biopsy samples obtained after 18 months and 3 years. The primary endpoint was time to prostate cancer progression, which was defined as either pathological progression or therapeutic progression. The term therapeutic progression referred to the decision to start prostate cancer treatment.

By 3 years, 54 (38%) of 144 dutasteride-treated men had prostate cancer progression (pathological or therapeutic) versus 70 (48%) of 145 control patients (hazard ratio [HR], 0.62; 95% CI, 0.43-0.89), P = .009).

By 18 months, 142 men in the dustasteride group and 144 men in the control group had undergone at least 1 post-baseline biopsy. Disease progression was documented in 32 (23%) dutasteride-treated and 50 (35%) placebo-treated men (HR, 0.56; 95% CI, 0.36-0.87).

Sexual adverse events or breast enlargement or tenderness was reported by 35 (24%) men who received the 5α-reductase inhibitor and 23 (15%) control patients. Eight (5%) men in the dutasteride and 7 (5%) controls had cardiovascular adverse events.

The researchers also assessed anxiety related to prostate cancer and prostate cancer treatment at 3 years using the Memorial Anxiety Scale for Prostate Cancer (MAX-PC) questionnaire. The questionnaire is a validated 24-item scale that evaluates prostate-cancer-related general anxiety, fear of recurrence, and anxiety specifically related to prostate-specific antigen testing.

Results showed that men treated with dutasteride had significantly lower overall anxiety scores than controls. The authors said that the decreased anxiety was largely due to a reduction in their fear of recurrent disease.

The researchers acknowledged that the potential for side effects related to 5α-reductase inhibitor therapy may be a concern for some patients. Nonetheless, their results demonstrate for the first time that dutasteride may be a “beneficial adjunct” to active surveillance in the low-risk prostate cancer population.

Fleshner NE, Lucia MS, Egerdie B, et al. Dutasteride in localised prostate cancer management: the REDEEM randomised double-blind, placebo-controlled trial [published online ahead of print January 24, 2012]. Lancet. 2012;379(9821):1103-1111.