Illuminating anthracycline cardiotoxicity: the renaissance of evidence-based onco-cardiology

Anthracyclines are potent anti-cancer agents known to cause cardiotoxicity and heart failure since the 1970s (1). For patients that have managed to survive cancer, heart failure from the chemotherapy that saved them can be a cruel and deadly irony. Despite decades of research, anthracycline cardiotoxicity remains an incompletely understood disease, with the most widely accepted concepts summarized as follows: it is dose dependent with doses less than 400-450 mg/m² thought to be generally safer (2); it can occur very early or very late after exposure (3); and it exemplifies Type 1 cardiotoxicity and is therefore irreversible (4). These notions, acquired over the past five and a half decades, have arisen from retrospective observational studies that have been either too small or too confounded to serve as solid evidence. In addition, many questions have remained unanswered because of the surprisingly complex nature of the disease, inconsistent definitions of cardiotoxicity, evolving technologies used to assess it, lack of large prospective studies, and an historic paucity of interaction between cardiologists and oncologists. As a result, the many published consensus and position statements from different societies are based on soft scientific evidence and thereby met with skepticism (5-7). Not surprisingly, there is great inconsistency in the care of these patients, by oncologists and cardiologists alike, and cardiotoxicity surveillance and practices vary widely among institutions.