Effects of Statins on All-Cause Mortality in Patients with Breast Cancer: A Population-Based Study.

This retrospective cohort study investigated the effects of statin use on 5-year clinical outcomes, particularly all-cause mortality, in patients with breast cancer. Clinical data of 971,808 patients who received a diagnosis of breast cancer between 2010 and 2020 were collected from the TriNetX platform. Eligible patients were classified as statin users (98,761) or nonusers (691,644). Statin use was defined by a prescription of statins being given within 3 years after breast cancer diagnosis. All-cause mortality and cardiovascular incidence were evaluated from Aalen-Johansen cumulative incidence curves. After 1:1 propensity score matching, all-cause mortality outcomes were analyzed in terms of hazard ratios and risk ratios. Our studies revealed that the risk of all-cause mortality was lower in statin users than in nonusers (hazard ratio: 0.798; risk ratio: 0.721; < 0.001). Subgroup analysis revealed that the protective effect of statins against all-cause mortality was more pronounced in older patients; those with a higher body mass index; and those with higher cholesterol, triglyceride, or low-density lipoprotein levels. The effects were prominent also in patients with estrogen receptor-negative or progesterone receptor-negative tumors. Statin use was associated with improved survival in patients with breast cancer, particularly older patients, those with hormone receptor-negative tumors, and those with metabolic dysregulation. Our findings indicate a possible link between statin use and reduced mortality in breast cancer patients, warranting further investigation in prospective controlled studies.