Bens A, et al. - In this large Danish cohort study of breast cancer survivors (n=52,723), researchers explored the link between post-diagnosis use of low-dose aspirin and risk of contralateral breast cancer (CBC). They identified all women recorded with a first primary breast cancer in the Danish Breast Cancer Cooperative Group Database between 1996 and 2012, and obtained information on drug use, tumor and patient characteristics, treatment, and CBC from nationwide registries. Time-varying post-diagnosis low-dose aspiring use was defined as ≥ 2 prescriptions filled during follow-up; researchers applied a 1-year exposure lag. A total of 1,444 women among those identified developed CBC during a median follow-up of 4.8 years. Researchers did not observe any substantial variation in hazard ratios according to pattern of low-dose aspirin use or estrogen receptor status of the first or the CBC. Findings showed no strong evidence regarding a relationship between post-diagnosis use of low-dose aspirin and risk of CBC.