PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: WBC at least 3,500/mm3 Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: AST less than 3 times upper limit of normal (ULN) Bilirubin normal Renal: Creatinine less than 1.5 times ULN Cardiovascular: No New York Heart Association class III or IV heart disease Metabolic: Oral intake at least 1,200 calories per day Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No uncontrolled infection No known seizure disorder No other malignancy within the past 5 years except nonmelanoma skin cancer or carcinoma in situ of the cervix No other medical or psychiatric condition that would interfere with compliance