Resection of colonic carcinoma with curative intent must encompass: (1) margins of bowel wall that are wider than the extent of microscopic intramural tumor spread beyond the macroscopic edge of the tumor; (2) lymphatic tissue draining the tumor and possibly containing cancer cells; (3) structures adhering to the tumor and possibly infiltrated by tumor cells. The minimal extent of resection that satisfies these requirements and possible benefits of extending the resection are reviewed. J. Surg. Oncol. 2008;98:603-606. © 2008 Wiley-Liss, Inc.