Risk of myocardial infarction and stroke after female breast cancer: analysis on a cohort of 1.3 million women

Abstract Background Breast Cancer (BC) is a leading public-health issue affecting women on a global scale, accounting for about 500,000 new cases every year in Europe. Thanks to the widespread implementation of screening programs and the improvement in therapies, women with BC live longer but they also are more likely to experience an increased risk of other diseases, including second primary cancer, cardiovascular, and metabolic diseases. Reasons for this increased risk include genetics, shared risk factors, and adverse effects from BC treatment. Methods To analyse the risk of myocardial infarction (MI) and stroke in women with BC considering the potential side effects of treatments, we used data from the Piedmont Longitudinal Study, an administrative cohort based on the record-linkage among census data and several health-administrative databases to include than 4 million inhabitants of an Italian region. Results Among 1,342,333 women ranging from 30 to 75 years old 19,203 had a BC diagnosis in the follow-up period, of whom 206 experienced a subsequent MI and 203 a stroke. Women with BC showed an increased risk for MI (HR: 1.20; 95%CI: 1.05–1.38) and for stroke (HR: 1.58; 95%CI: 1.38–1.82). Chemotherapy seemed to be the major risk factor for MI in BC women, while no different risk by therapy was found for stroke. Conclusion The results of this study supported the hypothesis about the toxic effect of therapies, suggesting both clinicians to routinely and actively screen for these treatment-related toxicities in women with BC and researchers to prioritize personalized treatments in order to minimize potentially devastating side effects.