PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: Platelet count at least 100,000/mm3 Hemoglobin at least 9.0 g/dL Absolute granulocyte count at least 1,500/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL AST/ALT no greater than 3 times upper limit of normal (ULN) (5 times ULN if liver metastases) PT/PTT normal Renal: Creatinine no greater than 1.5 mg/dL Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No active infection No serious concurrent systemic disorders that would preclude study treatment