PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 70-100% Life expectancy: Not specified Hematopoietic: WBC at least 3,000/mm3 Neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL AST no greater than 3 times upper limit of normal (ULN) (5 times ULN if liver metastases) No known Gilbert's disease Renal: Creatinine no greater than 1.5 mg/dL Calcium less than 12.0 mg/dL No symptomatic hypercalcemia Cardiovascular: No unstable angina No New York Heart Association class III or IV cardiac disease Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No active or uncontrolled infection No history of seizure disorder No uncontrolled diabetes mellitus, defined as random blood sugar 250 mg/dL or greater