Prognostic Value Of Inferior Mesenteric Artery Lymph Node Metastasis And A Scoring System To Predict Its Involvement In Rectal Cancer

Objective: The aim of this study is to assess the prognostic impact of dissection ofpositive inferior mesenteric artery (IMA) node on patients with stage III rectal cancerand to establish a prediction scoring system for IMA lymph node metastasis.Methods: A retrospective study was performed in264patients with stage III rectalcancer undergoing curative surgery. Clinicopathological, survival, and recurrence datawere compared between29patients with positive IMA nodes and235patients withnegative IMA nodes. Clinicopathological data which were found to be significantlyassociated with IMA nodal status were incorporated into a scoring system.Results: Survival analysis showed that5-year disease-free survival rate (5-DFS) and5-year overall survival (5-OS) in the positive IMA node group (24.4and27.6%,respectively) were significantly lower than in the negative IMA node group (61.8and71.3%, respectively)(P<0.001). Furthermore, multivariate analysis indicated thatIMA lymph node metastasis was an unfavorable independent prognostic factor for5-DFS and5-OS. In the training samples, tumor differentiation and preoperativeserum CEA were significant predictors of IMA node metastasis in multivariateanalysis, which were incorporated into a scoring system. Using receiver operatingcharacteristic curve analysis, we determined a cutoff value of46.5for scores, at whichthe system’s sensitivity was86%and specificity61%. When applied to testingsample, the sensitivity was80%and specificity60%. Conclusion: IMA lymph node metastasis is an independent poor prognostic factorfor stage III rectal cancer. The prediction scoring system for IMA node metastasiswould be beneficial in determining the appropriate level of IMA ligation.