Exposure to Anthracyclines During Childhood Causes Cardiac Injury

The use of anthracyclines in the treatment of acute lymphoblastic leukemia is limited by associated cardiotoxic effects, which can result in cardiomyopathy and congestive heart failure, and may be irreversible. Anthracycline-induced cardiotoxicity in long-term survivors of childhood cancer is characterized by reduced left ventricular wall thickness and mass, which is indicative of decreased cardiac muscle and depressed left ventricular contractility which is indicative of unhealthy heart muscle. Risk factors for anthracycline-induced cardiotoxicity include high cumulative anthracycline doses, high anthracycline dose intensity, and radiotherapy. Radiotherapy in patients with cancer treated with anthracyclines can exacerbate anthracycline-induced cardiac tissue damage. Several studies have shown that cardiomyopathy disease progression can be delayed in adults by using angiotensin-converting enzyme inhibitors such as enalapril. Studies in long-term survivors of pediatric cancer showed that enalapril has significant benefits in preventing cardiac functional deterioration on a short-term basis, but this is not sustained. Anthracycline-associated cardiotoxic effects can be combated by preventing cardiac injury during chemotherapy administration. There is evidence that dexrazoxane significantly reduces the cardiotoxicity associated with anthracyclines such as daunorubicin, doxorubicin, and epirubicin in adult patients with a wide range of tumor types. A study of the efficacy of dexrazoxane in reducing doxorubicin-induced cardiotoxicity in children and adolescents with high-risk acute lymphoblastic leukemia, showed that significantly fewer dexrazoxane-treated patients (21%) had elevated serum cardiac troponin (a biomarker of acute myocardial injury) levels than patients treated with chemotherapy alone (50%; P <.001). Dexrazoxane was also shown to have no effect on the event-free survival rate at 2.5 years, emphasizing that it does not detrimentally affect the efficacy of anthracycline therapy.