Cardiotoxicity of Contemporary Breast Cancer Treatments Opinion statement Treatment-related cardiotoxicity remains a significant concern for breast cancer patients undergoing cancer treatment and extends into the survivorship period, with adverse cardiovascular (CV) outcomes further compounded by the presence of pre-existing CV disease or traditional CV risk factors. Awareness of the cardiotoxicity profiles of contemporary breast cancer treatments and optimization of CV risk factors are crucial in mitigating cardiotoxicity risk. Assessment of patient- and treatment-specific risk with appropriate CV surveillance is another key component of care. Mismatch between baseline cardiotoxicity risk and intensity of cardiotoxicity surveillance can lead to unnecessary downstream testing, increased healthcare expenditure, and interruption or discontinuation of potentially life-saving treatment. Efforts to identify early imaging and/or circulating biomarkers of cardiotoxicity and develop effective management strategies are needed to optimize the CV and cancer outcomes of breast cancer survivors.