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) (no greater than 5 times ULN if liver metastases present) No Gilbert's Disease Renal: Creatinine no greater than 1.5 mg/dL Serum calcium less than 12.0 mg/dL No symptomatic hypercalcemia Cardiovascular: No unstable angina No active angina No New York Heart Association class III or IV heart disease No uncontrolled asymptomatic congestive cardiac failure At least 6 months since any myocardial infarction Pulmonary: No interstitial pulmonary fibrosis Other: No history of seizure disorder and receiving phenytoin, phenobarbital, or other antiepileptic medication No active or uncontrolled infection No uncontrolled diabetes mellitus Not pregnant or nursing Fertile patients must use effective contraception