Influence of pre-diagnosis statin use on survival among patients with pancreatic cancer.

Abstract

427 Background: Recent studies have suggested associations between statin use and enhanced survival among patients with pancreatic ductal adenocarcinoma (PDAC). We aimed to explore the impact of pre-diagnosis statin treatment on survival across different agents and exposure levels. Methods: We conducted a retrospective cohort study on 2,142 pancreatic cancer patients diagnosed from 2006-2014 in an integrated healthcare system. Patients were identified from an internal cancer registry and followed until censored at death, date of last contact, or end of study. We used electronic pharmacy records to abstract information on the type, length and dosage of all statin exposures in the year prior to diagnosis. The overall influence of statins as well as the individual effects of simvastatin, lovastatin, atorvastatin, pravastatin and rosuvastatin were assessed using Cox proportional hazards regression. All analyses were adjusted for age, race, stage, receipt of surgery, receipt of chemotherapy and Charlson comorbidity index. We further adjusted for cholesterol control to determine whether statins acted through a lipid-mediated pathway. Results: Overall statin use was associated with a 13% decrease in the risk of mortality (HR 0.87, CI 0.79-0.97). Specifically, those who had used statins for 9-12 months (HR 0.85, CI 0.75-0.95), received higher doses (40+ mg/day) (HR 0.86, CI 0.76-0.98) or were active users at diagnosis (HR 0.86, CI 0.78-0.96) all had better survival compared to non-statin users. When assessing the individual statins, we found similar improvements in survival only among simvastatin users. Further stratified analyses revealed that simvastatin decreased the risk of death by 26% in stage IV patients (HR 0.74, CI 0.64-0.85), but had no effect for stage I-III patients (pinteraction= 0.03). Cholesterol control did not impact any of the associations between statin use and survival. Conclusions: We found that pre-diagnosis statin use, specifically simvastatin, was associated with improved survival in pancreatic cancer patients.