NBME Surgery Shelf Practice Test

In colon cancer the operation aims for an oncologic resection: remove the tumor-bearing segment of colon with adequate margins and remove the regional lymphatic drainage. The lymph nodes along the mesentery are the first sites where cancer can spread, so taking them out as part of the resection serves both curative and staging purposes. This is accomplished with a segmental colectomy that includes the involved colon segment plus its mesentery (regional lymphadenectomy). That combination provides clearance of potential microscopic nodal disease and allows accurate pathologic staging, which guides adjuvant therapy and prognosis. Local polypectomy wouldn’t address invasive cancer beyond a surface polyp and could leave nodal disease behind. A colectomy with ileostomy would divert stool and is not the standard reconstruction for a localized lesion unless specific circumstances require diversion. Total colectomy is more extensive than needed for a localized tumor and carries greater morbidity. Therefore, segmental colectomy with regional lymphadenectomy best represents the standard approach.