PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Hematopoietic: WBC greater than 3,500/mm3 Platelet count greater than 130,000/mm3 Hemoglobin greater than 9 g/dL Hepatic: Bilirubin less than 2 times upper limit of normal (ULN) AST less than 2 times ULN Alkaline phosphatase less than 2 times ULN Renal: Creatinine less than 1.5 times ULN Other: No active or uncontrolled infection No second malignancy within 3 years except: Nonmelanomatous skin cancer In situ cervical cancer No pregnant or nursing women Negative pregnancy test required within 7 days prior to entry Effective contraception required of fertile patients