S0713: Oxaliplatin, Capecitabine, Cetuximab, and RT Followed By Surgery in Pts W/Stage II or III Rectal Cancer

RATIONALE: Drugs used in chemotherapy, such as oxaliplatin and capecitabine, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Monoclonal antibodies, such as cetuximab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Radiation therapy uses high-energy x-rays to kill tumor cells. Giving chemotherapy and radiation therapy before surgery may make the tumor smaller and reduce the amount of normal tissue that needs to be removed.
PURPOSE: This phase II trial is studying the side effects and how well giving oxaliplatin, capecitabine, and cetuximab together with radiation therapy followed by surgery works in treating patients with stage II or stage III rectal cancer.