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.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.