Combination Chemotherapy in Treating Patients With Metastatic Colorectal Cancer That Cannot Be Removed By Surgery

DISEASE CHARACTERISTICS:

* Histologically proven adenocarcinoma of the colon or rectum

  * Metastatic disease

    * No metastases involving only the bone
* Inoperable disease (i.e., not suitable for complete surgical resection)
* Measurable or evaluable disease

  * Measurable disease defined as ≥ 1 unidimensionally measurable lesion ≥ 20 mm by conventional CT scan OR ≥ 10 mm by spiral CT scan
* No symptomatic ascites or pleural effusion that has not been evacuated
* No CNS metastasis

PATIENT CHARACTERISTICS:

* WHO OR ECOG performance status 0-2
* Absolute neutrophil count ≥ 1,500/mm\^3
* Platelets ≥ 100,000/mm\^3
* Creatinine \< 3 times upper limit of normal (ULN)
* Alkaline phosphatase \< 5 times ULN
* No peripheral neuropathy ≥ grade 1
* No total or partial bowel obstruction
* Not pregnant or nursing
* Fertile patients must use effective contraception
* No uncontrolled hypercalcemia
* No other concurrent or prior malignancy, except adequately treated carcinoma in situ of the uterine cervix or basal or squamous cell carcinoma of the skin or cancer in complete remission for ≥ 5 years
* No uncontrolled congestive heart failure
* No angina pectoris
* No hypertension
* No arrhythmias
* No history of significant neurologic or psychiatric disorders
* No active infection
* No other serious nonmalignant disease

PRIOR CONCURRENT THERAPY:

* No prior chemotherapy and/or immunotherapy for metastatic disease
* Prior adjuvant chemotherapy allowed provided progression-free interval after completion of adjuvant chemotherapy is \> 6 months
* No other concurrent anticancer treatment
* No participation in another clinical trial with any investigational drug within 30 days prior to randomization
* No other concurrent investigational treatment
* No concurrent radiotherapy
* No concurrent cold cap for prevention of alopecia or iced mouth rinses for prevention of stomatitis