Doxorubicin is an effective antineoplastic agent, but it frequently causes 
dose-related cardiotoxic effects. Because the atrial natriuretic peptide (ANP) 
level is elevated in children with heart defects, the authors measured the ANP 
levels in children to determine whether ANP might serve as a simple diagnostic 
indicator of cardiotoxic effects. Sixteen patients, 5 to 19 years of age, who 
were being treated with doxorubicin (45 mg/m2 body surface area) for various 
malignancies had ANP levels measured in plasma. There was a group of six 
children, with a significant peak of plasma ANP (pANP) levels 3 weeks after the 
administration of the drug. Of these six patients, five had received high 
cumulative doses of doxorubicin (160 to 370 mg/m2), and two of them went into 
congestive heart failure without a previous decline in left ventricular ejection 
fraction, a standard technique for monitoring cardiac function during treatment 
with doxorubicin. The other ten patients had normal ANP levels throughout the 
study, and signs of cardiac dysfunction did not develop. None of the patients in 
the control group who had cancer and were not treated with doxorubicin and none 
of the healthy volunteers had elevated ANP levels. These preliminary results 
suggest that pANP may be useful as an early and sensitive indicator for 
doxorubicin-related myocardial damage.