PATIENT CHARACTERISTICS: Age: Over 18 Performance status: SWOG 0-2 Life expectancy: Not specified Hematopoietic: Absolute granulocyte count greater than 1,000/mm3 Platelet count greater than 100,000/mm3 Hepatic: Bilirubin no greater than 2 times upper limit of normal (ULN) (no greater than 3 times ULN if liver metastasis present) AST or ALT no greater than 2 times ULN (no greater than 5 times ULN if liver metastasis present) Renal: Creatinine no greater than 1.25 times ULN Cardiovascular: No myocardial infarction within the past year No congestive heart failure Other: No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer, or carcinoma in situ of the cervix Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for at least 6 months after study No medical, social, or psychological factor that would interfere with compliance