PATIENT CHARACTERISTICS: Age: 18 and over Performance status: WHO 0-2 Life expectancy: Not specified Hematopoietic: Absolute neutrophil count at least 2,000/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL SGOT no greater than 2.5 times normal (5 times normal if known liver metastases) Renal: Creatinine no greater than 1.5 mg/dL Other: No severe concurrent infection Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception