PATIENT CHARACTERISTICS: Age: Over 18 Performance status: Karnofsky 50-100% Life expectancy: At least 8 weeks Hematopoietic: Granulocyte count greater than 1,500/mm3 Hemoglobin greater than 9 g/dL Platelet count greater than 100,000/mm3 Hepatic: SGOT and SGPT no greater than 3 times normal (5 times normal if liver tumor present) Bilirubin no greater than 2.0 mg/dL Renal: Creatinine no greater than 2.0 mg/dL Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception