Previous studies have raised concerns that 5-alpha reductase inhibitors (5-ARIs) might increase the risk of high-grade prostate cancer (PCa), but new research confirms that 5-ARIs are associated with no greater risks compared with alpha-adrenergic blockers (ABs).
The PCPT (Prostate Cancer Prevention Trial) and REDUCE (Reduction by Dutasteride of Prostate Cancer Events) had found increases in Gleason 7 to 10 PCa among men treated with 5-ARIs for benign prostatic hyperplasia (BPH), investigators noted. The findings from the current study suggested that these associations stemmed rather from detection and surveillance biases.
“Similar to prior studies, we found an increased prevalence of high-grade prostate cancers diagnosed among men who were exposed 5-ARIs for the treatment of lower urinary tract symptoms related to BPH,” lead investigator Lauren P. Wallner, PhD, MPH, of the University of Michigan in Ann Arbor, told Renal & Urology News. “However, this increase in the diagnosis of high-grade tumors did not translate into an increased risk of prostate cancer death among these men.”
Dr Wallner and her team analyzed a cohort of 174,895 men from Kaiser Permanente health systems who were newly treated for BPH and lower urinary tract symptoms between 1992 and 2007. Unlike previous studies on the subject, they specifically examined PCa mortality in a representative population and considered the impact of medication dose and duration.
Each patient treated with a 5-ARI (or a combination of a 5-ARI and AB) was matched to 6 AB users with similar ages, race, and BPH medication initiation. A separate case-control study also was conducted with 1671 matched men to capture all relevant PCa cases.
Over 19 years of follow up, 1053 men died of PCa, including 15% of 5-ARI users and 85% of AB users. Analyses revealed no greater risk of PCa-specific mortality among ARI users from either the cohort or case-control study after adjustment for competing causes of death.
The findings in Mayo Clinic Proceedings, published online ahead of print, corroborated other recent studies on the topic. “Therefore, our findings provide additional reassurance about the safety of using 5ARIs in practice to manage lower urinary tract symptoms related to BPH,” Dr Wallner stated.
1. 1. Wallner LP, DiBello JR, Li BH, et al. 5-Alpha Reductase Inhibitors and the Risk of Prostate Cancer Mortality in Men Treated for Benign Prostatic Hyperplasia. Mayo Clin Proc doi: 10.1016/j.mayocp.2016.07.023 [Epub ahead of print].