Cardiotoxicity of monoclonal antibody-based therapies in breast cancer: a contemporary narrative review

Monoclonal antibody-based therapies have substantially improved outcomes in breast cancer, particularly through HER2-directed treatment strategies, but have also introduced important cardiovascular toxicities that require careful recognition and management. This narrative review summarizes current evidence on cardiotoxicity associated with monoclonal antibody therapies used in breast cancer, with emphasis on HER2-targeted antibodies, antibody-drug conjugates, and selected immune checkpoint inhibitors.Trastuzumab remains the best-characterized monoclonal antibody associated with cancer therapy-related cardiac dysfunction, most commonly presenting as left ventricular systolic dysfunction, particularly in patients previously exposed to anthracyclines or with baseline cardiovascular risk factors. Pertuzumab and currently available antibody-drug conjugates have not shown a major increase in cardiotoxic risk beyond that observed with established HER2-directed therapy, although long-term data remain limited for some newer agents. Immune checkpoint inhibitors are less commonly associated with cardiovascular toxicity, but may rarely cause severe immune-mediated complications, particularly myocarditis and also non-immune mediated toxicity such as cardiac dysfunction.Contemporary evaluation of cardiotoxicity increasingly relies on an integrated cardio-oncology framework incorporating left ventricular ejection fraction, global longitudinal strain, and cardiac biomarkers, with growing recognition of subclinical dysfunction and right ventricular involvement. Current management strategies emphasize baseline cardiovascular risk assessment, risk-adapted surveillance, early initiation of heart failure therapy when indicated, and individualized multidisciplinary decision-making regarding continuation of anticancer treatment, including permissive cardiotoxicity in selected patients.As the use of monoclonal antibody therapies continues to expand, optimizing the balance between oncologic efficacy and cardiovascular safety remains a central goal of modern breast cancer care.