PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Life expectancy: At least 12 weeks Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 9.0 g/dL Hepatic: Bilirubin no greater than 2.0 mg/dL ALT and AST no greater than 3 times upper limit of normal (ULN) (5 times ULN if liver metastases present) Renal: Creatinine no greater than 1.5 mg/dL OR Creatinine clearance at least 60 mL/min No gross hematuria Cardiovascular: No uncontrolled cardiac arrhythmia No myocardial infarction within the past 6 months Other: No other malignancy within the past 5 years except adequately treated carcinoma in situ of the cervix or basal cell or squamous cell skin cancer No severe concurrent disease, infection, or comorbidity that would preclude study No other unstable medical conditions No psychiatric disorders that would preclude study Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for at least 6 months after study