Clinical significance of lymph node ratio and location of nodal involvement in patients with right colon cancer.

BACKGROUND/AIMS Increasing negative lymph node count has been reported to be associated with better outcomes in patients with colon cancer. The present study aimed to clarify the clinical significance of the lymph node ratio (LNR) and location of lymph node metastasis (LNM) in patients with stage III right colon cancer. METHODS We enrolled 820 patients who had undergone curative resection due to colon cancer at a single institution between 1991 and 2005. Among them, 197 underwent curative resection for T2-T4 right colon cancer. We evaluated the oncological outcomes according to LNR (quartiles) and distribution of LNM (n1 = LNM adjacent to the colon or along the vascular arcades of the marginal arteries; n2 = LNM along the major vessels; n3 = LNM near the roots of the major vessels). RESULTS The rates of LNM in T2, T3 and T4 right colon cancer were 11.1, 38.6 and 58.0%, respectively (p < 0.0001). Recurrence rates were 27.3, 37.5 and 57.1% in patients with n1, n2 and n3 LNM, respectively (p < 0.0001). LNR (p < 0.0001) and distribution of LNM (p = 0.046) were independent risk factors for recurrence in patients with stage III right colon cancer. CONCLUSIONS Some patients with extensive LNM benefited from lymph node dissection with high ligation. Those with T3-T4 right colon cancer are suitable candidates for lymph node dissection with high ligation. Adding the concept of LNR and location of LNM to conventional TNM staging could improve the accuracy of evaluating nodal status.