PATIENT CHARACTERISTICS: Age: 3 to 21 at diagnosis Performance status: Not specified Hematopoietic: ANC greater than 1,500/mm3 Platelet count greater than 100,000/mm3 Hemoglobin greater than 10 g/dL Hepatic: Bilirubin less than 1.5 mg/dL ALT less than 1.5 times normal Renal: Nuclear glomerular filtration rate or creatinine clearance greater than 70 mL/min per 1.73 square meters