This research also found loss of imprinting in normal colon cells taken from CRC patients, suggesting that the entire colon may be at risk of developing a precancerous growth or malignant tumor. Other diagnostic tests may be used to assess the extent of the disease, especially whether the disease has metastasized, including computed tomography of the abdomen. Liver function should also be assessed. CEA may be elevated with other gastrointestinal tumors and nonmalignant conditions, such as pulmonary emphysema and active ulcerative colitis. In addition, it is the best form of palliation for patients with incurable or advanced disease.
Larger lesions require laparoscopic or open surgical procedures.
Generally, a right hemicolectomy is indicated for tumors involving the cecum and ascending colon, whereas an extended right hemicolectomy is indicated for tumors involving the hepatic flexure. A transverse colectomy is indicated for tumors involving the transverse colon. A left hemicolectomy is performed when cancer involves the splenic flexure and descending colon and a sigmoid colectomy for tumors of the sigmoid. If possible, transanal resection is indicated for rectal carcinoma. Adequate surgical margins and total excision of draining lymphatics should be performed as well.