PATIENT CHARACTERISTICS: Age: Under 4 years Performance status: Not specified Life expectancy: At least 12 weeks Hematopoietic: Absolute granulocyte count greater than 1,500/mm3 WBC greater than 4,000/mm3 Platelet count greater than 100,000/mm3 Hepatic: Bilirubin less than 1.5 mg/dL SGPT less than 90 IU/dL Renal: Creatinine clearance greater than 80 mL/min