PATIENT CHARACTERISTICS: Age: 15 and over Performance status: ECOG 0-2 Hematopoietic: WBC at least 4,000/mm3 Platelet count at least 100,000/mm3 Hepatic: SGOT no greater than 4 times normal Bilirubin no greater than 2 mg/dL Renal: Creatinine no greater than 2.5 mg/dL Other: No active uncontrolled infection Not pregnant or nursing Fertile patients must use effective contraception