Androgen deprivation therapy and statin therapy in prostate cancer patients.

Abstract

205 Background: Metastatic prostate cancer (mPC) is treated with androgen deprivation therapy( ADT). Duration of response to ADT predicts patient’s survival. It has been shown in observational studies that concurrent statin use may prolong response to ADT. Studies in mice have shown negative interactions. We wanted to examine the effect of this interaction in patients being followed at Mayo Clinic Arizona (MCA). Methods: We examined 441 patients with mPC, who received ADT and were treated at MCA from year 2011 to 2017. . Our study evaluated the time to progression (TTP) and overall survival(OS) for patients with mPC on ADT with or without concurrent statin use. Among the patients who were evaluated, there was a subset of 156 patients taking abiraterone (ABI). Characteristics were compared between statin users and nonusers using Chi squared test and Wilcoxon rank-sum tests. The primary outcome was TTP defined as the duration from ADT initiation to disease progression. The association between statin use and TTP was analyzed by multivariable Cox regression to estimate hazard ratios (HRs) and 95% Conference Interval (CI), and adjusted for Gleason score, primary therapy type, prior ADT, metastatic status, and PSA at ADT initiation. Results: There was no significant difference in TTP when comparing patients with statin to those without a statin. The HR for statin use vs no statin use is 1.049 with CI (0.838, 1.314) and p-value is 0.677. There was no significant difference in overall survival when comparing statin vs no statin use. The HR for statin use vs no statin use was 0.928(CI 0.642, 1.342) with p-value at 0.693. In the ABI population, there was no significant difference in TTP for patients with statin vs no statin. HR was 1.00 CI (0.725, 1.377) with p-value at 0.998. For overall survival, there was no significant difference with HR at 0.852 (CI 0.502, 1.446) with p-value at 0.553. Conclusions: Despite retrospective studies showing benefit of use of statin in men with prostate cancer, our study observed no difference in long term outcomes. Possible explanations could be smaller sample size, inability to verify data as medication intake was not verified directly. Also, patient’s compliance with medications could be a confounding variable.