PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: Granulocyte count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL SGOT no greater than 3 times upper limit of normal No known Gilbert's syndrome Renal: Creatinine no greater than 1.5 mg/dL Calcium no greater than 12 mg/dL No symptomatic hypercalcemia under treatment Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No history of seizures No serious concurrent infections or nonmalignant medical illnesses that are uncontrolled or whose control may be jeopardized by study complications No psychiatric disorders that would preclude study compliance No other active malignancy within the past 5 years except nonmelanoma skin cancer or carcinoma in situ of the cervix No uncontrolled diabetes mellitus (i.e., random blood sugar less than 250 mg)