Impact of 5-ALPHA reductase inhibitor use on prostate cancer risk at the time of urology referral.

Abstract

226 Background: 5-alpha reductase inhibitors (5-ARIs) are commonly used medications for the treatment of lower urinary tract symptoms caused by benign prostatic hyperplasia. One of the consequences of 5-ARI use is a 50% drop in serum PSA without a concomitant reduction in prostate cancer (PCa) risk. Previous work has suggested that 5-ARI use is associated with worse PCa-specific outcomes. The objective of this study was to evaluate the impact of 5-ARI use on patients’ PCa risk at the time of referral from primary care to urology. Methods: This retrospective cohort study included all men ≥ 40 years who had a PSA resulted between 2018-2019 and were seen in an ambulatory setting. PSA testing was determined through laboratory data in the electronic health record (EHR). Clinical and demographic data were collected for all men. 5-ARI use was determined through orders in the EHR. Men were assigned PCa risk according to both the Prostate Biopsy Collaborative Group (PBCG) and Prostate Cancer Prevention Trial (PCPT) risk calculators. PSA values were doubled for 5-ARI users prior to calculating risk. Referral to urology for PCa risk was determined using the narrative reason for referral associated with the referral order. Results: Between 2018-2019, 91,368 men had a PSA test, including 2,939 5-ARI users, and 88,429 non-users. Uncorrected median PSA and the proportion of men referred to urology for PCa risk were similar between the two groups (p = 0.60 and p = 0.17, respectively). Of men referred to urology for PCa risk, 5-ARI users had similar uncorrected PSA to non-users (p=0.86) but higher risk for high grade PCa once PSA correction was performed, median (IQR) 48% (24%) vs 28% (18%) using the PBCG and 21% (17%) vs 10% (10%) using the PCPT (p < 0.01 for both) (Table). Conclusions: Men taking 5-ARIs have significantly higher risk for high-grade PCa at time of referral to urology than non-users in this cohort. As the unadjusted PSA at referral to urology for PCa risk was the same between 5-ARI users and non-users, this indicates that the effect of 5-ARI use on serum PSA levels is not routinely accounted for when assessing PCa risk. Further study on interventions to account for 5-ARI use when screening for PCa are warranted. [Table: see text]