 RATIONALE: 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. Drugs used in chemotherapy, such as gemcitabine, 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. Sometimes when chemotherapy is given, it does not stop the growth of tumor cells. The tumor is said to be resistant to chemotherapy. Giving cetuximab together with chemotherapy may reduce drug resistance and allow the tumor cells to be killed. Giving cetuximab and chemotherapy before surgery may make the tumor smaller and reduce the amount of normal tissue that needs to be removed. Radiation therapy uses high-energy x-rays to kill tumor cells. 