Clinical analysis of metastatic characteristics of infrapyloric lymph nodes (No.206) and terminal ileum lymph nodes in patients with right colon cancer

BACKGROUND: D3 or complete mesocolic excision (CME) surgery has become a common surgical procedure for the treatment of colon cancer metastasis. Clinical misuse and overuse of lymph node dissection bring unnecessary burdens to patients. A detailed guidance for lymph node dissection in patients with T3 and T4 stage right colon cancer at different locations is urgently needed. METHODS: A retrospective study was performed. Patients received D3 or CME surgery were divided into ileocecal group, ascending colon group, and hepatic flexure group according to the 9th edition of the Japanese Society for Cancer of the Colon and Rectum guidelines. The distributions of lymph node metastases were analyzed according to tumor infiltration depth (T stage) and tumor location. RESULTS: The incidence of metastases in the paracolic area (or station), intermediate area, and main (or central) area was 38.4% (139/362), 12.7% (46/362), and 9.7% (35/362), respectively. The proportion of patients having No.206 and terminal ileum lymph nodes metastases was 7.7% (14/181) and 3.7% (9/244), respectively. No.206 lymph node metastasis is related to tumor location (χ(2) = 7.955, p = 0.019) and degree of differentiation (χ(2) = 18.99, p = 0.000), and terminal ileum lymph node metastasis is related to tumor location (χ(2) = 6.273, p = 0.043). Patients with T3/T4 hepatic flexure cancer received radical right hemicolectomy in addition to No.206 lymph node dissection. CONCLUSION: Radical right hemicolectomy and No.206 group lymph node dissection are necessary for T3 and T4 stage colon cancer therapy.