PATIENT CHARACTERISTICS: Age: 15 and over Performance status: ECOG 0-2 Life Expectancy: At least 12 weeks Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count greater than 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL SGOT and SGPT no greater than 2 times normal Renal: Creatinine no greater than 1.5 mg/dL OR Creatinine clearance at least 60 mL/min Cardiovascular: No history of acute myocardial infarction within the past 6 months No clinically significant cardiac arrhythmias No New York Heart Association class III or IV disease Other: HIV negative No GI bleeding or bleeding tendency Not pregnant or nursing Effective contraception required for fertile patients