A Study of Radiotherapy in Rectal Cancer Using Oxaliplatin, Capecitabine With or Without Cetuximab

Primary Objectives To estimate the pathological complete response rate following neoadjuvant radiotherapy with concurrent capecitabine and oxaliplatin, with or without cetuximab based on the KRAS mutation status in rectal cancer. Secondary Objectives 1. To evaluate the incidence of grade 3-4 toxicities with each of the two neoadjuvant regimens and during the 30-day post-operative period. 2. To estimate the clinical tumour response rate and sphincter preservation rate with each of the two neoadjuvant regimens. 3. To correlate EGRF gene amplification with pathological response rate in those treated with cetuximab. 4. To estimate the pattern of failure. 5. To establish an annotated tissue library with samples being obtained prior to therapy and following therapy (at the time of surgery).