Statin use at the time of initiation of androgen deprivation therapy (ADT) and time to progression (TTP) in patients with hormone-sensitive prostate cancer.

Abstract

148 Background: Statin use has been associated with a decreased risk of recurrence after local therapy and a lower risk of prostate cancer mortality. There is little known about the association between statin use and prostate cancer progression among men newly initiating ADT. We undertook an analysis of the association between statin use at the time of ADT initiation and TTP. Methods: We queried our institutional clinical database (Prostate CRIS), which captures clinicodemographic data, treatment details, and clinical outcomes of our prostate cancer patients (pts), to identify pts treated with ADT for biochemical recurrence or metastatic disease. Date of progression and statin use at ADT initiation were collected by medical record review. Progression was defined as 3 PSA rises. Date of progression was defined as date of first rise (nadir + >0.02 ng/ml). The association between statin use and TTP on ADT was estimated from multivariable Cox regression, adjusting for known prognostic factors: biopsy Gleason score, primary therapy type, metastatic status, and PSA at ADT initiation. Results: Of the 926 patients eligible for analysis, 283 (31%) were taking a statin at ADT initiation. Statin users were less likely to have M1 (11 vs. 18%) or N1 (5 vs 10%) disease at diagnosis and more likely to have received local therapy +/-ADT compared to nonusers. They were also less likely to have metastases at ADT initiation (53 vs 63%). Median PSA at diagnosis and at ADT initiation were lower among statin users. Duration from diagnosis to ADT initiation was longer in users. After a median follow-up of 5.8 years, 644 pts (70%) had progressed on ADT and median TTP on ADT was 20.3 months (95% CI: 18,24). Men on statins had a longer median TTP on ADT compared to nonusers (27.5 vs 17.4 months). The association remained statistically significant after adjusting for known prognostic factors [adjusted HR=0.83 (p=.039)]. Conclusions: In our cohort, statin use at the time of ADT initiation was associated with a significant increase in TTP on ADT even after adjusting for established prognostic factors. Further investigation into the mechanisms behind this observation is planned.