a system of staging colorectal tumors based on evaluation of the depth of invasion of the carcinoma and the presence or absence of metastasis. The four stages are: A, confined to the mucosa and submucosa; B, invasion through the muscularis without lymph node involvement; C, invasion through the muscularis with regional node metastasis; and D, tumor metastasis to distant sites. See illustration.
a staging system for colorectal tumors, from A to D, according to the degree of tissue invasion and metastasis. A Dukes' A tumor is one that is confined to the mucosa and submucosa. A B tumor is one that has invaded the musculature but has not involved the lymphatic system. C tumors have invaded the musculature with metastatic involvement of the regional lymph nodes. D tumors are those that have metastasized to distant organ tissues.