Histologic types of colon cancer include the following:Adenocarcinoma (most colon cancers).Mucinous (colloid) adenocarcinoma.Signet ring adenocarcinoma.Scirrhous tumors.Neuroendocrine. Tumors with neuroendocrine differentiation typically have a poorer prognosis than pure adenocarcinoma variants.References: Saclarides TJ, Szeluga D, Staren ED: Neuroendocrine cancers of the colon and rectum. Results of a ten-year experience. Dis Colon Rectum 37 (7): 635-42, 1994.
Treatment decisions should be made with reference to the TNM classification system, rather than the older Dukes or the Modified Astler-Coller classification schema. The American Joint Committee on Cancer (AJCC) and a National Cancer Institute-sponsored panel recommended that at least 12 lymph nodes be examined in patients with colon and rectal cancer to confirm the absence of nodal involvement by the tumor.[2,3,4] This recommendation takes into consideration that the number of lymph nodes examined is a reflection of both the aggressiveness of lymphovascular mesenteric dissection at the time of surgical resection and the pathologic identification of nodes in the specimen. Retrospective studies, such as Intergroup trial INT-0089 [EST-2288], have demonstrated that the number of lymph nodes examined in colon and rectal surgery may be associated with patient outcome.[5,6,7,8]The staging system does not apply to the following histologies:Sarcoma. (See the