Direct Tumor Invasion in Colon Cancer: Correlation with Tumor Spread and Survival

This study examined the correlation between depth of local invasion in colon cancer and tumor spread and patient survival. A cohort of 796 patients with a complete set of TNM staging information following an elective resection for colon cancer was selected. The rates of lymph node and distant metastasis, tumor differentiation, and extramural venous invasion for different tumor (T) categories were compared. The effects of initial tumor (T) category on overall patient survival were studied. The depth of local tumor invasion correlated strongly with nodal involvement (P = 0.0001), rates of extramural venous invasion (P = 0.0002), poor differentiation (P = 0.0001), and distant metastasis (P = 0.0001). Fifty-seven percent of the patients remained lymph node-negative and distant metastasis-negative irrespective of their depth of tumor invasion had no impact on overall survival (P = 0.49). For patients with lymph node or distant metastasis (43 percent), depth of tumor invasion had significant impact on overall survival (P = 0.001). Thirteen percent of T3N1, 33 percent of T3N2, 40 percent of T4N1, and 68.percent of T4N2 cases had distant metastasis at presentation. Two types of colon cancer were observed: locally active and tendency to metastasize. For the latter, overall mortality and the risk of metastasis increased with depth of tumor invasion.