The Surgical Management of Colon Cancer
Surgery remains the primary treatment modality for colon cancer. Prior to surgery, all patients should be clinically staged with a total colon exam; computed tomography scanning of the chest, abdomen, and pelvis; and measurement of serum CEA level. The principles of surgical resection for colon cancer include four components. First, the colon and its mesentery should be resected along the planes to keep its fascia intact. Second, the primary vessel to the resected segment of the colon should be ligated at its origin. Third, a wide mesenteric resection should be performed to ensure a harvest of at least 12 lymph nodes. Finally, the tumor should be resected with at least a 5 cm distal or proximal margin. Resection of the primary tumor can be approached either open or laparoscopically. The Clinical Outcomes of Surgical Therapy (COST) Study Group, Conventional versus Laparoscopic-Assisted Surgery in Colorectal Cancer (CLASICC), and COlorectal cancer Laparoscopic or Open Resection (COLOR) trials demonstrated that the laparoscopic approach was not inferior to open resection of colon cancers. There are several technical approaches to resecting right- and left-sided cancers, which include medial to lateral, lateral to medial, posterior, or superior and medial to lateral and lateral to medial, respectively. The management of obstructing and perforated cancers presents unique challenges. Resection of obstructing cancers provides the most effective treatment of the primary tumor and the obstruction. Endoscopic stenting as a bridge to surgery is an effective option in selected patients. Perforated cancers can present as acutely with free spillage of feculent material or subacutely with contained contamination. In either case, the best cancer-related outcome is associated with an oncologic resection. Improvements in the chemotherapy regimens for metastatic colon cancer have greatly changed the management of these patients. Patients with metastatic disease and an asymptomatic primary tumor should receive chemotherapy as the first line of therapy. The rate of the primary tumor-developing symptoms in this setting is quite low. For patients who present with bleeding or obstructive symptoms, surgical resection should be the first line of therapy. The long-term cancer-related outcomes for colon cancer are dependent upon the tumor, node, and metastasis (TNM) stage of the tumor, the quality of the surgical resection, and when indicated the timely administration of adjuvant chemotherapy.