PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 3 months Hematopoietic: ANC at least 2,000/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 10 g/dL Hepatic: Bilirubin less than 1.5 mg/dL Transaminases normal (no greater than 2.5 times normal if liver metastases) Alkaline phosphatase normal (no greater than 2.5 times normal if liver or bone metastases) No history of chronic liver disease, e.g., chronic active hepatitis, cirrhosis Renal: Creatinine no greater than 1.4 mg/dL Creatinine clearance at least 60 mL/min Other: No active bacterial infection (e.g., abscess) or with fistulae No grade 2 or worse neurotoxicity No concurrent medical condition that precludes treatment No history of alcoholism, drug addiction, or psychotic disorder Not pregnant or nursing Fertile patients must use effective contraception