Defining Cardiovascular Endpoints in Oncology Trials: Challenges and Opportunities: A Scientific Statement From the American Heart Association

The unprecedented expansion of approved oncology therapies has prolonged survival and transformed the prognosis for many patients diagnosed with cancer. However, cancer treatments may be associated with cardiovascular toxicities that manifest through vascular, myocardial, or metabolic pathways, potentially limiting the use of cancer therapeutics and adversely affecting outcomes. Oncology clinical trials provide an important opportunity to evaluate cardiovascular safety signals by generating data on the incidence, timing, and spectrum of toxicities. However, progress has been limited by inconsistent definitions and variable approaches to event characterization. This scientific statement aligns the advances in cardiovascular medicine and cardiovascular clinical trials to provide criteria for systematic selection, rigorous characterization, and adjudication of cardiovascular endpoints in contemporary oncology trials. The proposed framework links drug-specific mechanisms to endpoint selection and standardizes the approach to definitions of adverse cardiovascular events, including heart failure, arrhythmias, myocarditis, and thrombotic events. Definitions of major adverse cardiac events, clinical events, and surrogate endpoints are discussed, along with strategies for alignment with the Common Terminology Criteria for Adverse Events and patient-reported outcomes. Practical guidance is provided for prospective surveillance, decentralized and hybrid clinical trial designs, independent endpoint adjudication, and statistical approaches to competing risks and late-emerging toxicities. By harmonizing cardiovascular endpoint assessment across oncology trials, this scientific statement aims to enhance risk stratification, facilitate regulatory acceptance, and inform clinical decision making, ultimately improving patient safety while supporting innovation in cancer therapeutics.