PATIENT CHARACTERISTICS: Age: 18 and over Performance status: 0-2 Life expectancy: Not specified Hematopoietic: Absolute neutrophil count at least 2,000/mm3 WBC at least 4,000/mm3 Platelet count at least 100,000/mm3 Hepatic: ALT or AST no greater than 2.5 times upper limit of normal (ULN) (no greater than 5 times ULN if liver metastasis present) Renal: Creatinine no greater than 1.5 times ULN Cardiovascular: No evidence of severe or uncontrolled cardiovascular disease Pulmonary: No evidence of severe or uncontrolled pulmonary disease Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception