Dukes’ classification, 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. Compare TNM staging system.
