RATIONALE: Monoclonal antibodies, such as cetuximab and bevacizumab, 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. Bevacizumab may also stop the growth of tumor cells by blocking blood flow to the tumor.Drugs used in chemotherapy, such as leucovorin, oxaliplatin, and fluorouracil, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving cetuximab together with combination chemotherapy and bevacizumab before surgery may make the tumor smaller and reduce the amount of normal tissue that needs to be removed. Giving these treatments after surgery may kill any tumor cells that remain after surgery.