The association between statin use and outcomes in patients initiating androgen deprivation therapy.

Abstract

145 Background: Studies are conflicting regarding the association between statin use and biochemical recurrence after surgery or radiotherapy for localized prostate cancer. A handful of studies have observed favorable associations between statins and prostate cancer-specific (PCSM) and overall mortality (OS), however, this has not been studied in an advanced disease cohort nor has the combination of statins and androgen deprivation therapy (ADT) been specifically studied. Methods: Patients with PSA >3 ng/mL after >1 year following primary or salvage radiotherapy (RT) were enrolled in a randomized trial of intermittent (IAD) vs. continuous (CAD) ADT (NCT00003653). Statin use at baseline and during the study was captured and modeled as a time-dependent covariate. The primary end-point was OS. Models were adjusted for age, time from RT to ADT and PSA at baseline. As results were nearly identical between the IAD and CAD arms they are reported as aggregates unless otherwise indicated. Results: Of 1,364 patients enrolled, 585 (43%) reported statin use during the study. Statin users were younger (72.7 vs. 73.8, p=0.001) and less likely to have PSA >15 (20 vs. 25%, p=0.04). Median follow-up was 6.9 years and 524 deaths occurred. Statin use was associated with a reduced risk of overall death (HR: 0.64; 95% C.I. 0.53 – 0.78, p<0.001) and PCSM (HR: 0.64, 95% C.I. 0.48 – 0.86, p=0.003). Statin users had 14% longer time to castration resistance but this did not reach statistical significance (p=0.15). In the IAD arm, statin users had more off-treatment intervals (p=0.04) and longer time off-treatment (median: 0.85 vs. 0.64 years, p=0.06). Across 6 functional domains, statin users reported better quality of life scores. Conclusions: In men treated with ADT following primary or salvage RT, statin use was associated with improved overall and prostate cancer-specific survival and improved quality of life. In patients treated with IAD, statin use was associated with more off-treatment intervals and longer time off-treatment. A prospective trial of statins in men commencing ADT is warranted to confirm this observation.