 This is a study to assess the efficacy and safety of the addition of cetuximab to the combined regimen of capecitabine, oxaliplatin and bevacizumab in patients with previously untreated advanced colorectal carcinoma. It is an open, comparative study, comparing the effects of capecitabine, oxaliplatin and bevacizumab to those of the same regimen plus cetuximab. 