Cardio-oncology: protecting the heart from curative breast cancer treatment
Patients with breast cancer have higher rates of cardiovascular disease than age-matched controls. Anthracyclines and trastuzumab increase the risk of heart failure (HF) and radiation increases the risk of ischemic heart disease, valvular disease and HF. Older age, low normal ejection fraction, history of coronary artery disease (CAD), cardiac risk factors, higher cumulative anthracycline exposure, combination anthracycline and trastuzumab and/or radiation all increase the risk of cardiac events post treatment. Clinical prediction models (CPMs) and/or genetic testing may be useful in guiding treatment decisions but further external validation is necessary. Screening for asymptomatic cardiotoxicity using echocardiography after completion of therapy is reasonable in patients receiving anthracyclines and/or radiation, especially in those with traditional cardiac risk factors such as hypertension, diabetes, hyperlipidemia, and obesity or with low normal baseline left ventricular ejection fraction (LVEF). Elevated cardiac troponins during anthracycline therapy and early reductions in myocardial deformation may predict subsequent reductions in LVEF but further research is needed to demonstrate clinical benefit to routine screening and early treatment. Neurohormonal antagonist therapy with ACEi/ARBs and beta-blockers are indicated in patients with reduced ejection fraction and ongoing research will clarify the role for neurohormonal antagonists and statins for the prevention of breast cancer therapy cardiotoxicity. Patients treated for breast cancer should be educated on the evidence for optimal lifestyle behaviors such as not smoking, regular exercise, healthy diet and maintaining a healthy weight in reducing the risk of cardiovascular disease. Traditional cardiac risk factors such as hypertension, diabetes and hyperlipidemia should be optimally managed to reduce the risk of cardiovascular events in patients treated for breast cancer.