Statin use and female reproductive organ cancer risk in a large population-based setting

Statins are an effective and commonly used cholesterol-lowering medication class, but their hypothesized effects on cancer risk remain uncertain. We evaluated the association between statin use and endometrial as well as ovarian cancer risks.

We conducted a retrospective study with two cohorts of women aged 45-89 years during 1990-2004 within an integrated healthcare delivery system. Information on statin use and covariates were obtained from automated databases. We identified cancer cases through the Surveillance, Epidemiology, and End Results registry. Multivariable Cox proportional hazards models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CI) for incident invasive endometrial and ovarian cancers among statin users compared to nonusers.

Women were followed for a median of about six years. Among 73,336 women studied, 568 endometrial cancer cases were identified. During the study period, 6% of women used statins for at least one year and the median duration of use was 3.1 years. Although not statistically significant, we found a reduction in endometrial cancer risk among statin users (HR = 0.67; 95% CI: 0.39-1.17) compared to nonusers. We identified 326 ovarian cancer cases in a cohort of 93,619 women. There was also a nonsignificant decrease in ovarian cancer risk among statin users (HR = 0.69; 95% CI: 0.32-1.49).

Our study does not support an association between statin use and endometrial as well as ovarian cancers, but a reduced risk cannot be ruled out.