BPH drug may lower prostate cancer incidence, effect on mortality unknown
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Dutasteride (Avodart) reduced the risk of prostate cancers and precursor lesions and improved outcomes related to benign prostatic hyperplasia (BPH) among men, a study concluded.
The Reduction by Dutasteride of Prostate Cancer Events (REDUCE) study was done in collaboration with the drug's maker, GlaxoSmithKline. The four-year, multicenter, randomized, double-blind, placebo-controlled, parallel-group study compared dutasteride, 0.5 mg daily, to placebo in men 50 to 75 years of age with a prostate-specific antigen (PSA) level of 2.5 to 10.0 ng/mL and one negative prostate biopsy (6 to 12 cores) within six months before enrollment. Results were reported in the April 1 New England Journal of Medicine.
Cancer was detected via biopsy or surgery in 659 of the 3,305 men in the dutasteride group and 858 of 3,424 men in the placebo group (relative risk reduction, 22.8%; 95% CI, 15.2 to 29.8; P<0.001). Among the 6,706 men who underwent a needle biopsy, there were 220 tumors with a Gleason score of 7 to 10 among 3,299 men in the dutasteride group and 233 among 3,407 men in the placebo group (P=0.81). In the placebo group, men with prostate cancer were withdrawn from the study, so during years 3 and 4, there were 12 tumors with a Gleason score of 8 to 10 in the dutasteride group, as compared with only 1 in the placebo group (P=0.003).
Researchers wrote that while dutasteride therapy may have played a role in reducing the number of cancers with Gleason scores of 8 to 10, more men in the placebo group may have had their tumors upgraded had the study protocols not required they be withdrawn. Researchers also said the data support the idea that the difference in the number of cancers with a Gleason score of 8 to 10 was due in part to dutasteride therapy.
However, an accompanying editorial cautioned that dutasteride (and finasteride, another drug in the 5a-reductase inhibitors class) do not prevent prostate cancer, but only shrink tumors that have a low potential for mortality. “The use of these drugs for prevention may be somewhat risky,” the editorial continued. “Because PSA levels are suppressed, men may have a false sense of security, and if prostate cancer ever develops, the diagnosis may be delayed until they have high-grade disease that may be difficult to cure.”