PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 2.0 mg/dL ALT/AST 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 OR Creatinine clearance at least 50 mL/min Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No uncontrolled serious medical or psychiatric illness