NEW YORK (Reuters Health) – While the risk of prostate cancer appears to be reduced in men taking dutasteride, there are indications that cancer may emerge once the drug is discontinued.
That finding comes from a 2-year follow-up of men who had participated in the 4-year REDUCE trial, which compared prostate cancer rates in men receiving the 5-alpha-reductase inhibitor (5ARI) dutasteride versus those given placebo.
The REDUCE trial included men at increased risk of prostate cancer due to older age (50-75 years) and increased PSA levels (2.5-10 ng/mL) with a prior negative prostate biopsy. Compared to placebo, dutasteride reduced the relative risk of biopsy-detectable prostate cancer during the study by 22.8%.
The main aim of the current REDUCE Follow-Up Study was to assess the occurrence of prostate cancer in the 2 years following the conclusion of the REDUCE study. A total of 2751 of the original participants were enrolled. During that time, no drugs were provided and all biopsies were performed for cause.
Very few prostate cancers were detected during follow-up, but there more in the former dutasteride group. Specifically, there were 14 cases among former dutasteride recipients compared to 7 among the former placebo group, report Dr. Robert L. Grubb, at Washington University School of Medicine in St. Louis, Missouri, and colleagues.
They suggest, in their report in the March issue of the Journal of Urology, “A possible reason for this difference is that any prostate cancer that may have been suppressed by dutasteride during REDUCE was no longer being suppressed for those subjects who did not continue 5ARI therapy.”
This is supported by the fact that, among the former dutasteride-treated patients, prostate cancer rates during follow-up were 0.9% in those who continued to take a 5ARI compared to 1.3% for those who did not continue on a 5ARI, the authors point out.
Still, no high grade prostate cancers (Gleason score 8-10) were detected during the follow-up study in either the former dutasteride or placebo groups, according to the report, and no new safety issues emerged.
Dr. Grubb and colleagues caution that, while the study provides real-world observational data, it has limitations. No statistical tests were conducted, because the subjects were not randomized in the follow-up study, and most data were based on subject recollection.
Given that, they conclude only that findings show “a low rate of new prostate cancer diagnoses in the former placebo and dutasteride groups.”
SOURCE: The REDUCE Follow-Up Study: Low Rate of New Prostate Cancer Diagnoses Observed During a 2-Year, Observational, Followup Study of Men Who Participated in the REDUCE Trial
J Urol 2013;189:871-877.
