Cardiac toxicity of cancer treatment regimes in children and adolescents: physiopathology, clinical data and the paediatric oncologist's point of view

Over the last 20 years, the increase in the cure rate of childhood cancer and leukemia of almost 80% has facilitated the observation of middle and long-term sequelae, particularly of cardiovascular origin; such after-effects are the consequence of cytotoxic damage to the cells of the cardiovascular system, in particular by anthracyclines and radiotherapy, and all the more so by their combined use. Such destructive lesions to myocytes greatly hinder the capacity of the cardiac muscle to hypertrophy to meet the needs of bodily growth, pregnancy and certain intense sports activities. Endothelial cells also accelerate an early arteriosclerotic process, a potential cause of sudden death in the case of ostial stenosis. All such phenomena build up over time, together with the usual adult cardio-vascular risk factors. Finally, no cardiac tissue, pericardial, valvular endocardium or autonomic nervous tissue escapes these cytotoxic effects, giving rise to pericarditis, calcification, valvular leaks and arrythmias and conduction abnormalities. The resulting excessive cardiac mortality is one of the major concerns of paediatric oncologists, along with secondary tumours and leukaemia. This article analyses physiopathological consequences that are often asymptomatic or clinical, together with diagnostic, screening and follow-up methods for these patients, encouraging lifestyle modifications where appropriate or, when possible, treatment before the appearance of cardiac failure, myocardial infarction or sudden death. Other cytotoxic drugs such as high-dose cyclophosphamide, amsacrin, 5-FU and tubulin acting agents are also mentioned as a result of their cardiac toxicity, but this is not usually dose-cumulative.