Statin Use and Risk of Vascular Events Among Cancer Patients After Radiotherapy to the Thorax, Head, and Neck

BACKGROUND: This study aimed to explore whether statins reduce radiation‐induced vascular complications in cancer patients postradiotherapy to the thorax, head, and neck. METHODS AND RESULTS: We conducted a retrospective cohort study within a provincial linked database of 5718 cardiac patients with thorax and head or neck cancer having undergone radiotherapy between 2000 and 2011. One thousand five hundred fifty‐two patients were identified as nonstatin users and 4166 as statin users. The primary outcome of interest was the composite of cerebrovascular (transient ischemic attack, and fatal or nonfatal stroke) or cardiovascular events (fatal or nonfatal myocardial infarction). Time‐dependent Cox proportional hazard analyses were performed. The crude event rate was 10.31% for nonusers and 9.03% for statin users (hazard ratio of 0.92 [95% CI 0.76–1.10, P=0.3451]), over a mean time to event/censoring of 534±687 days for nonusers and 594±706 days for the statin users. After adjusting for age, sex, prior history of stroke/transient ischemic attack or myocardial infarction, diabetes mellitus, dyslipidemia, atrial fibrillation, chronic kidney disease, heart failure, and hypertension, statin use postradiotherapy was associated with a nonsignificant 15% relative risk reduction, but a strong trend toward reducing the primary outcome (hazard ratio=0.85 95% CI 0.69–1.04, P=0.0811). The use of statins was associated with a significant reduction of 32% for the outcome of stroke alone (hazard ratio=0.68, 95% CI 0.48–0.98, P=0.0368). CONCLUSIONS: Statin use post radiation therapy was associated with a significant reduction in stroke, with a trend toward significantly reducing cardiovascular and cerebrovascular events.