PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: Absolute neutrophil count at least 1500/mm3 Platelet count at least 100,000/mm3 Hepatic: SGOT no greater than 5 times upper limit of normal (ULN) Bilirubin no greater than 1.5 mg/dL OR Bilirubin no greater than 2 times ULN in patients with biliary stents or percutaneous biliary catheters Renal: Creatinine no greater than 1.5 mg/dL Cardiovascular: No New York Heart Association class III or IV heart disease Other: Nutritional intake at least 1200 kcal/day No uncontrolled infection or chronic debilitating disease Not pregnant or nursing Fertile patients must use effective contraception No uncontrolled seizure disorder No prior malignancy within 5 years except adequately treated basal cell/squamous cell carcinomas and adequately treated noninvasive carcinomas