PATIENT CHARACTERISTICS: Age: Under 21 Performance status: Not specified Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Cardiovascular: Shortening fraction greater than 27% on echocardiogram (ECHO) OR Left ventricular ejection fraction greater than 47% on radionuclide scan (RCNA) OR Cardiac function assessed as within normal limits by cardiologist ECHO or RCNA obtained as close as clinically possible to start of therapy