N-terminal-proB-type natriuretic peptide as a marker for acute anthracycline cardiotoxicity in children

Background: Anthracyclines are widely used in the treatment of pediatric cancer but their use is associated with cardiotoxicity. The cardiotoxic effect may become clinically apparent many years after therapy, and no reliable method exists for early detection of cardiac damage while the patient is receiving the drug. The natriuretic peptides have been established as markers for anthracycline-induced cardiotoxicity in adults and markers for cardiac dysfunction in children. We examined whether N-terminal proB-type natriuretic peptide (NT-proBNP) may be used as a marker for anthracycline-induced cardiotoxicity in children. Methods: Twenty-three consecutive pediatric patients with newly diagnosed cancer were enrolled in this study. All patients received anthracycline-containing chemotherapy. Fifty-four age-matched children served as controls. Serial measurements of plasma NT-proBNP levels were taken before and after each anthracycline-containing course. Echocardiograms were performed before initiation of treatment and at the end of the study. Results: Plasma levels of NT-proBNP were within normal limits before treatment and increased significantly only after the first anthracycline dose (from 150 +/- 112 to 327 +/- 321 pg/mL, mean +/- SD, P = 0.02) and not after subsequent doses. This increase was attributed mainly to a subgroup of patients who received more than 25 mg/m(2) of doxorubicin. In 14 patients (61%), the highest NT-proBNP level occurred after the first anthracycline dose. All patients had normal echocardiograms and none developed heart failure. Conclusions: NT-proBNP increases significantly after the first anthracycline course in a subset of pediatric cancer patients. This increase is not associated with clinical or echocardiographic evidence of cardiac dysfunction. Anthracyclines may be more cardiotoxic in the first course than in subsequent courses. Longer follow-up of these patients is necessary to determine whether NT-proBNP can be used as an early marker for anthracycline-induced cardiotoxicity.