Cancer Therapy-Related Cardiac Dysfunction: Unresolved Issues

An increasing awareness of chemotherapy and radiotherapy as preventable causes of cardiac failure among large numbers of patients surviving cancer has contributed to the development of cardio-oncology as a subspecialty. Perhaps the most important driver has been that the aging of the population undergoing cancer therapy has provided an increasing number of patients at risk for the development of heart failure. Cardio-oncology has many unresolved questions. In this article the 6 most important unresolved issues requiring additional research are discussed: (1) the frequency of overt heart failure as a manifestation of cardiotoxicity; (2) the optimal diagnostic approach to cardiotoxicity in the context of large numbers of patients requiring repeated testing; (3) the need for better risk prediction; (4) alternatives to the use of ejection fraction as the cornerstone of evaluation; (5) definition of the best strategy for protection; and (6) the need for evidence-based algorithms to guide late follow-up. When this evidence base is mature, we will have a better understanding of the magnitude of the problem of cardiotoxicity, who best to screen (and how), who justifies the use of cardioprotective therapy, and how all at-risk patients should be followed over the decades following cancer therapy.