PATIENT CHARACTERISTICS: Age: Not specified Menopausal status: Not specified Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: Absolute granulocyte count greater than 1,500/mm3 Hemoglobin greater than 9.0 g/dL Platelet count greater than 100,000/mm3 Hepatic: Bilirubin no greater than 2.0 mg/dL AST/ALT no greater than 3 times upper limit of normal (ULN) (no greater than 5 times ULN in case of liver metastases) Renal: Creatinine no greater than 2.0 mg/dL Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception Must be able to have daily fluid intake of at least 3 liters No concurrent active infection No other prior malignancy in past 5 years except adequately treated basal cell carcinoma of the skin or carcinoma in situ of the cervix