Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically confirmed metastatic or recurrent adenocarcinoma
of the colon or rectum that is incurable by surgery or radiation therapy A metastatic
lesion in the liver or lung should be evaluated for definitive surgical treatment before
being considered for this study Measurable disease required Elevated CEA, hepatomegaly
ascites, pleural effusion, positive nuclear scan or bone scan, or poorly defined pelvic or
abdominal mass are NOT considered measurable disease Must have measurable disease outside
the radiation port or progression of disease within a previously radiated area Must be
eligible for a biopsy of a malignant lesion No ascites that are detectable on physical
exam No brain metastasis

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy:
Greater than 12 weeks Hematopoietic: WBC at least 4,000/mm3 Granulocyte count at least
1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.2 mg/dL
SGOT less than 4 times upper limit of normal Renal: Creatinine no greater than 1.5 mg/dL
or Creatinine clearance at least 60 mL/min Other: No history of any other malignancy
except curatively treated nonmelanoma skin cancer and carcinoma in situ of the cervix No
active infection or other serious medical conditions deemed unacceptable Negative
pregnancy test Effective contraception required of all fertile patients

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior
chemotherapy for advanced disease Endocrine therapy: Not specified Radiotherapy: See
Disease Characteristics At least 3 weeks since prior radiotherapy Surgery: At least 3
weeks since any surgical procedure