PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Hemoglobin at least 9.0 g/dL Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL SGOT/SGPT no greater than 2 times upper limit of normal (ULN) (5 times ULN if liver metastases present) Renal: Creatinine no greater than 1.5 mg/dL Cardiovascular: No active congestive heart failure No uncontrolled angina No myocardial infarction within the past 6 months Other: Fertile patients must use effective contraception No uncontrolled pain requiring irradiation No concurrent serious infection No other malignancy within the past 5 years except nonmelanoma skin cancer No overt psychosis, mental disability, or incompetence