Combination of Cetuximab, Capecitabine, and Oxaliplatin With or Without Bevacizumab

Research has shown that the more drug treatments patients with cancer of the colon or rectum receive, the longer they live. One uses the drugs capecitabine and oxaliplatin which all patients on this study will receive. Bevacizumab is an antibody which blocks blood flow to tumors and increases how long patients with colorectal cancer live. However, it can increase the risk of stroke and heart attack. Bevacizumab is currently a standard part of treatment for colorectal cancer. Cetuximab is an antibody which blocks a protein called EGFR which shrinks colorectal cancer. It may be helpful with initial chemotherapy and with bevacizumab. One goal of this study is to find out the response rate (chance of tumor shrinking) with two treatments for colorectal cancer. All patients will get capecitabine, oxaliplatin and cetuximab. Half will receive bevacizumab. All drugs in this study are approved to treat colorectal cancer. This research study is being done to find the best, safest way to combine these therapies.