Statin use and the risk of breast cancer: a population-based case-control study

Objective: The aim of this study was to investigate whether the use of statins was associated with breast cancer risk. Background: Experimental studies have shown that statins have potential protective effects against cancer. Methods: We conducted a population-based case-control study in Taiwan. Cases consisted of all patients who were aged 50 years and older and had a first-time diagnosis of breast cancer for the period between 2004 and 2011. The controls were matched to cases by age, sex and index date. Adjusted odds ratios (ORs) and 95% CIs were estimated by using multiple logistic regression. Results: We examined 565 breast cancer cases and 2260 controls. The unadjusted OR for any statin prescription was 1.19 (95% CI = 0.95 - 1.49) and the adjusted OR was 1.13 (95% CI = 0.84 - 1.51). Compared with no use of statins, the adjusted ORs were 1.02 (95% CI = 0.61 - 1.69) for the group with cumulative defined daily doses (DDDs) below 44.67 DDDs, 1.21 (95% CI = 0.83 - 1.76) for the group with cumulative dose between 44.68 DDDs and 308 DDDs, and 1.10 (95% CI = 0.66 - 1.83) for the group with the highest cumulative dose (> 308 DDDs). Conclusions: The present data do not provide evidence to support either beneficial or harmful associations between statin use and breast cancer risk.