DISEASE CHARACTERISTICS: Histologically proven metastatic and/or locally recurrent adenocarcinoma of the colon or rectum that is not expected to be cured with standard therapy Patients who previously underwent definitive surgical resection and subsequently develop metastatic disease should have diagnosis reconfirmed with new histologic or cytologic specimen if: More than 5 years have elapsed since primary surgery OR Primary tumor was stage I or II At least 1 measurable lesion (2 cm or more in widest diameter) by CT or MRI scan No CNS metastases

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0 or 1 Life expectancy: Not specified Hematopoietic: Absolute neutrophil count greater than 1,500/mm3 Platelet count greater than 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL Renal: Creatinine no greater than 1.5 mg/dl Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for 6 months after study No underlying disease state associated with active bleeding No active infection requiring therapy No second malignancy within the past 5 years except curatively treated nonmelanomatous skin cancer

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy for metastatic disease At least 6 months since prior adjuvant chemotherapy with or without radiotherapy Endocrine therapy: Not specified Radiotherapy: Prior radiotherapy to nonindicator lesion allowed and recovered See Chemotherapy Surgery: See Disease Characteristics Other: No concurrent approved cancer therapy or other experimental therapy