There are over 430,000 cases of colorectal cancer diagnosed in the Western World (Western Europe and United States) each year, and over 50,000 deaths. Colorectal cancer is the second leading cause of cancer deaths. Colonic tumors arise as intramucosal epithelial lesions. As tumors grow, they invade the colon wall, lymph nodes and vascular structures, adjacent tissues, and distant sites, especially the liver.

The Dukes classification is the most commonly used for colon carcinoma staging. Dukes A describes a tumor limited to the bowel wall. In Dukes B the tumor has extended to pericolic fat, but the lymph nodes have no tumor involvement. In Dukes C there are already regional lymph node metastases, and the Dukes stage D is defined by the presence of metastases to organs like liver, lung, etc. Prognosis relates to the stage of the disease at the time of diagnosis. The survival rates at five years for the different Dukes stages are approximately 85% for Dukes A, 70% for Dukes B, 30% for Dukes C, and 10% for Dukes D. Also, the extension of the tumor at diagnosis determines the initial treatment.

However, prognosis is also affected by several other factors including the histologic grade of the tumor, DNA content (ploidy), gene abnormalities, etc.