PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 60-100% Life expectancy: At least 12 weeks Hematopoietic: Hemoglobin at least 9 g/dL WBC at least 3,000/mm3 Granulocyte count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 times upper limit of normal (ULN) ALT and/or AST no greater than 2.5 times ULN (no greater than 4.0 times ULN if liver or bone metastasis present) Alkaline phosphatase no greater than 2.5 times ULN (no greater than 4.0 times ULN if liver or bone metastasis present) Renal: Creatinine no greater than 1.5 times ULN OR Creatinine clearance at least 60 mL/min Other: Not pregnant or nursing Fertile patients must use effective contraception No history of other serious medical conditions