PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: Absolute neutrophil count greater than 1,500/mm3 Platelet count greater than 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL SGOT or SGPT no greater than 2 times upper limit of normal (ULN) (no greater than 5 times ULN if liver metastases present) Renal: Creatinine no greater than 2.0 mg/dL Cardiovascular: No active congestive heart failure Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No concurrent serious infection No other malignancy within past 5 years except nonmelanomatous skin cancer No overt psychosis, mental disability, or incompetence No life threatening illness