PATIENT CHARACTERISTICS: Age: 18 to 70 Performance status: WHO 0-2 Life expectancy: At least 3 months Hematopoietic: Neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.25 times upper limit of normal (ULN) AST/ALT no greater than 2 times ULN Alkaline phosphatase no greater than 2 times ULN Renal: Creatinine clearance at least 60 mL/min Creatinine no greater than 1.25 times ULN Neurologic: See Disease Characteristics Other: Not pregnant or nursing Fertile patients must use effective contraception No other malignant or nonmalignant diseases interfering with follow-up No psychological, familial, sociological, or geographical condition potentially hampering compliance with the study and follow-up