Impact of 5α-Reductase Inhibitors on Disease Reclassification among Men on Active Surveillance for Localized Prostate Cancer with Favorable Features

Abstract

We determined the effect of 5α-reductase inhibitors on disease reclassification in men with prostate cancer optimally selected for active surveillance. In this retrospective review we identified 635 patients on active surveillance between 2002 and 2015. Patients with favorable cancer features on repeat biopsy, defined as absent Gleason upgrading, were included in the cohort. Patients were stratified by those who did or did not receive finasteride or dutasteride within 1 year of diagnosis. The primary end point was grade reclassification, defined as any increase in Gleason score or predominant Gleason pattern on subsequent biopsy. This was assessed by multivariable Cox proportional hazards regression analysis. At diagnosis 371 patients met study inclusion criteria, of whom 70 (19%) were started on 5α-reductase inhibitors within 12 months. Median time on active surveillance was 53 vs 35 months in men on vs not on 5α-reductase inhibitors (p<0.01). Men on 5α-reductase inhibitors received them for a median of 23 months (IQR 6-37). On actuarial analysis there was no significant difference in grade reclassification for 5α-reductase inhibitor use in patients overall or in the very low/low risk subset. The overall percent of patients who experienced grade reclassification was similar at 13% vs 14% (p = 0.75). After adjusting for baseline clinicopathological features 5α-reductase inhibitors were not significantly associated with grade reclassification (HR 0.80, 95% CI 0.31-1.80, p = 0.62). Furthermore, no difference in adverse features on radical prostatectomy specimens was observed in treated patients (p = 0.36). Among our cohort of men on active surveillance 5α-reductase inhibitor use was not associated with a significant difference in grade reclassification with time.