Radiation Therapy and Capecitabine With or Without Oxaliplatin in Treating Patients Who Are Undergoing Surgery for Stage II or Stage III Rectal Cancer

Inclusion Criteria

• •DISEASE CHARACTERISTICS:
• •Histologically confirmed adenocarcinoma of the rectum
• •* T3-4, N0-2, M0 disease by endorectal ultrasound
• •* T2 disease located in the low rectum allowed provided lower pole is ≤ 6 cm from the anal verge
• •Tumor must be accessible to digital rectal examination (i.e., tumor located at low- or mid-rectum)
• •Resectable disease treatable with chemoradiotherapy
• •* No unresectable disease (i.e., T4 disease with high risk for incomplete gross resection \[i.e., R2\])
• •PATIENT CHARACTERISTICS:
• •Age
• •18 to 80
• •Performance status
• •ECOG 0-2
• •Life expectancy
• •Not specified
• •Hematopoietic
• •WBC ≥ 1,500/mm\^3
• •Platelet count ≥ 100,000/mm\^3
• •Hemoglobin \> 10 g/dL
• •Hepatic
• •Alkaline phosphatase normal
• •Bilirubin normal
• •Renal
• •Creatinine ≤ 130 μmol/L
• •No severe renal insufficiency
• •Cardiovascular
• •No cardiac insufficiency
• •No symptomatic coronary artery disease
• •Other
• •Not pregnant or nursing
• •Negative pregnancy test
• •Fertile patients must use effective contraception
• •No contraindication to study treatment
• •Prior acute intestinal obstruction allowed provided patient underwent surgical diversion with stoma
• •No history of other cancer except basal cell skin cancer or carcinoma in situ of the cervix
• •No peripheral neuropathy
• •No uncontrolled diabetes
• •No other uncontrolled severe disease
• •No geographical, social, or psychological condition that would preclude study follow-up
• •PRIOR CONCURRENT THERAPY:
• •Biologic therapy
• •Not specified
• •Chemotherapy
• •No prior chemotherapy for cancer
• •No other concurrent chemotherapy
• •Endocrine therapy
• •Not specified
• •Radiotherapy
• •No prior radiotherapy for cancer
• •Surgery
• •Not specified
• •Other
• •No concurrent phenytoin
• •No concurrent participation in another clinical trial of an experimental medical treatment