PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 3 months Hematopoietic: Absolute neutrophil count greater than 1,500/mm3 Platelet count greater than 100,000/mm3 Hepatic: Bilirubin less than 2.0 mg/dL SGOT less than 3 times upper limit of normal (ULN) (less than 5 times ULN if due to hepatic metastases) LDH less than 3 times ULN (less than 5 times ULN if due to hepatic metastases) Alkaline phosphatase less than 3 times ULN (less than 5 times ULN if due to hepatic metastases) Renal: Creatinine no greater than 1.5 mg/dL Other: No active infection requiring systemic therapy within 1 week prior to entry No significant concurrent illness No history of bleeding disorder or clotting factor deficiency No dementia or altered mental status that would prohibit informed consent Not pregnant or nursing Effective contraception strongly advised for fertile women