Inclusion Criteria

DISEASE CHARACTERISTICS:

- Biopsy-proven primary adenocarcinoma of the rectum

- Stage II or III disease

- The distal border of the tumor must be at or below the peritoneal reflection,
defined as within 12 cm of the anal verge by proctoscopic examination

- No recurrent disease

- Must have wild-type k-ras status

- Measurable and/or nonmeasurable disease

PATIENT CHARACTERISTICS:

- Zubrod performance status 0-2

- Leukocyte count ≥ 3,000/mcL

- Granulocyte count ≥ 1,500/mcL

- Platelet count ≥ 100,000/mcL

- Bilirubin ≤ 1.5 times upper limit of normal (ULN)

- Alkaline phosphatase ≤ 2.5 times ULN

- SGOT (serum glutamate oxaloacetate transaminase) or SGPT (serum glutamate pyruvate
transaminase)≤ 2.5 times ULN

- Creatinine clearance > 50 mL/min

- No prior severe reaction to a monoclonal antibody

- Willing to have specimens submitted

- No peripheral neuropathy ≥ grade 2

- No known existing uncontrolled coagulopathy

- No evidence of current high-grade obstruction

- At least 2 weeks since prior diverting procedure

- No history of allergy to platinum compounds or to antiemetics appropriate for
administration in conjunction with protocol treatment

- No prior unanticipated severe reaction to fluoropyrimidine therapy or known
sensitivity to fluorouracil or known DPD deficiency

- No active inflammatory bowel disease, malabsorption syndrome, or inability to swallow
that would impair the ingestion or absorption of capecitabine

- No uncontrolled intercurrent illness

- No ongoing or active infection

- No symptomatic congestive heart failure or unstable angina pectoris

- No cardiac arrhythmia or myocardial infarction within the past 12 months

- Not pregnant or nursing

- Fertile patients must use effective contraception

- No prior malignancy allowed except for adequately treated basal cell or squamous cell
skin cancer, carcinoma in situ of the cervix, or other cancer from which the patient
has been disease-free for 5 years

PRIOR CONCURRENT THERAPY:

- Recovered from any recent major surgeries (e.g., coronary artery bypass graft,
transurethral resection of prostate, or abdominal surgery)

- No prior chemotherapy, radiotherapy, or targeted therapy for this tumor

- More than 4 weeks since prior investigational agents

- No concurrent anti-retroviral therapy for HIV