PATIENT CHARACTERISTICS: Age: 18 to 75 Performance status: WHO 0-2 Life expectancy: At least 3 months Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 10 g/dL Hepatic: AST and ALT no greater than 3 times upper limit of normal (ULN) Bilirubin no greater than 1.5 times ULN Renal: Creatinine no greater than 1.10 mg/dL Cardiovascular: No uncontrolled cardiac disease Other: No other significant, uncontrolled underlying medical or psychiatric condition No serious active infection Neurologically stable No other prior malignancy except treated nonmelanomatous skin cancer or carcinoma in situ of the cervix Not pregnant or nursing Fertile patients must use effective contraception