**2. Primary treatment of colon cancer**

About 70–80% of patients diagnosed with localized non-metastatic colorectal cancer undergo curative resection which is the main modality of treatment for those with good performance status and acceptable comorbidities. This is achieved by surgical resection of the primary tumor, anastomosis of the bowel and removal of 12 or more regional lymph nodes. The aim of oncological resection is the complete removal of the tumor and potential lymphovascular spread with a clear margin of at least 5 cm proximally and distally for colon cancer, and minimal proximal margin of 5 cm and distal of 2 cm for rectal carcinoma. Circumferential/radial margin clearance of at least 1 mm is considered optimal. Endoscopic resection involves complete tumor resection and adjacent tissue in one block. This may be acceptable for those accept vigorous close surveillance and potential need for further surgical resection or those who are non-surgical candidates.
