PATIENT CHARACTERISTICS: Age: Over 1 Performance status: Lansky 80-100% Life expectancy: Not specified Hematopoietic: Lymphocyte count at least 500/mm3 Platelet count at least 30,000/mm3 Hemoglobin at least 8 g/dL (at least 1 week since transfusional support) Blood coagulation less than 25% above upper limit of normal (ULN) for age (WHO grade 0) Hepatic: Bilirubin less than 25% above ULN for age (WHO grade 0) Renal: Creatinine less than 25% above ULN for age (WHO grade 0) Cardiovascular: No significant history or current evidence of cardiovascular disease (e.g., uncontrolled hypertension, serious arrhythmias) Normal shortening fraction at cardiac ultrasonography Normal ECG Other: No evidence of active infections Normal chest x-ray Normal brain CT scan No other concurrent disease or second primary malignancy