Abstract P2-13-03: Statin use and breast cancer survival – a Swedish nationwide study

Abstract

Abstract Background: A sizeable body of evidence shows that statins can cease proliferation of breast cancer and prevent breast cancer recurrence. Given the epidemiological findings from other Scandinavian populations, we hypothesized that statins may have anticancer effects and therefore reduce cancer-related mortality in a Swedish population. This study investigates the association between both pre- and post diagnostic statin use and breast cancer outcome. Methods: A Swedish nation-wide retrospective cohort study of 20,559 Swedish women diagnosed with breast cancer (July 1st, 2005 through 2008). Dispensed statin medication was identified through the Swedish Prescription Registry. Breast cancer-specific death information was obtained from the national cause-of-death registry until December 31st, 2012. Cox regression models yielded hazard ratios (HR) and 95% confidence intervals (CI) regarding associations between statin use and breast cancer-specific and overall mortality. Results: During follow-up, a total of 4,678 patients died, whereof 2,669 were considered breast cancer-specific deaths. Compared to non- or irregular use, regular pre-diagnostic statin use was associated with lower risk of breast cancer-specific death (HR=0.77 (95%CI 0.63-0.95), P=0.014). When evaluating diabetes patients only (N=545), this association was strengthened (HR=0.63 (95%CI 0.40-0.98), P=0.044). Post diagnostic statin use was in similarity associated with lower risk of breast cancer–related death compared to non-use (HR=0.83 (95%CI 0.75-0.93), P=0.001). Conclusion: This study supports the notion that statin use is protective regarding breast cancer-specific mortality in agreement with previous Scandinavian studies, although less so with British studies. These disparities should be investigated further. Citation Format: Borgquist S, Broberg P, Olsson H. Statin use and breast cancer survival – a Swedish nationwide study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-13-03.