Colorectal cancer staging as a prognostic feature.

There are many factors which influence the prognosis for patients with colon and rectal cancer, including pre-existing disease such as familial polyposis and ulcerative colitis. Also gross characteristics of the tumor whether polypoid or invasive, the presence of vascular or lymphatic invasion, the degree of anaplasia and to some extent the method and extent of treatment are influencing factors. However, most important in the prognosis is the pathologic extent of disease. Dukes in 1932 proposed three stages: A: limited to the bowel wall; B: extending through the bowel wall; and C: any lesion with regional nodal involvement. The Dukes' classification has been modified on multiple occasions leading to confusion in evaluating and comparing data. To help clarify this problem, the American Joint Committee on Cancer has proposed staging recommendations based on the review of over 2000 cases of cancer of the large bowel.