PATIENT CHARACTERISTICS: Age: 18 and over Performance status: WHO 0-2 Life expectancy: At least 3 months Hematopoietic: Absolute neutrophil count at least 2,000/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin less than 1.5 mg/dL Other liver function tests no greater than 2 times upper limit of normal (unless related to liver metastases) Renal: Creatinine no greater than 1.4 mg/dL Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for 3 months after study No active bacterial infections No nonmalignant disease that would be incompatible with study No prior alcoholism, drug addiction, or psychotic disorders