Distribution of lymph node metastasis in T1 sigmoid colon carcinoma: should we ligate the inferior mesenteric artery?

Objective: In standard oncological sigmoid colectomy, the inferior mesenteric artery is ligated either at its origin or at the level of the left colic artery. However, in patients with early-stage carcinoma, the distribution of metastatic nodes may be limited. The aim of this study was to clarify the prevalence and distribution of lymph node metastasis in T1 sigmoid colon carcinoma and to determine the adequate range of lymph node dissection.

Materials And Methods: The study included 121 consecutive patients treated for T1 sigmoid colon carcinoma. Clinicopathologic factors associated with nodal metastasis and the distribution of metastatic nodes were analyzed.

Results: Of 121 patients, 12 (10%) had nodal involvement. The depth of invasion and the presence of lymphatic and vascular invasion were significantly associated with nodal metastasis. Of these 12 patients, 11 (92%) had lymph node metastasis confined to pericolic nodes. Nodes along the sigmoidal artery were involved in one patient. There was no involved node along the superior rectal artery or at the root of the inferior mesenteric artery.

Conclusions: Lymph node dissection for T1 sigmoid colon carcinoma should be limited to the root of the sigmoidal artery, and the inferior mesenteric artery should be preserved.