Background: The optimal extent of lymph node (LN) dissection remains controversial in adenocarcinoma of the esophagogastric junction (AEG), especially in Siewert types II and III. The aim of this study was to analyze clinicopathological characteristics of patients with Siewert type II and III AEGs to clarify whether pyloric (no. 5 and no.6) lymphadenectomy is essential in these patients.
Methods: A retrospective analysis was performed in the Third Affiliated Hospital of Soochow University from September 2008 to December 2012, and clinicopathological characteristics on all patients with Siewert type II and III AEGs, who underwent curative total gastrectomy with lymphadenectomy were collected. The index of estimated benefit from lymph node dissection (IEBLD) was used to evaluate the efficacy of lymph node dissection of no. 5 and no. 6. Both clinicopathological characteristics and IEBLDs were set as the standards in the assessment of the value of pyloric lymph nodes dissection.
Results: A total of 216 patients with AEG (Siewert type II: 141, Siewert type III: 75) were included into the study. Type III AEG had a larger tumor size and relatively advanced T stage compared to Type II AEG. The 5-year overall survival (OS) rates in type II and type III AEGs were almost similar (type II 50.4% vs. type III 46.7%, p = 0.782). There was a very low incidence of pyloric lymph nodes metastases in type II AEG (no. 5 is 1.4% and no. 6 is 0.7%). Hence, the IEBLDs of no. 5 and no. 6 lymph node were negligible regardless of the T stage and tumor differentiation. In type III AEG, metastasis rates of no. 5 and no. 6 lymph node were 9.3 and 5.3%, respectively. The IEBLDs of no. 5 and no. 6 lymph node were 2.7 and 1.3, respectively.
Conclusions: Based on the IEBLDs of pyloric lymph nodes, dissection of no. 5 and no. 6 lymph nodes were worthwhile for Siewert type III AEG but not essential for Siewert type II AEG.
Keywords: Adenocarcinoma of the esophagogastric junction; Lymphadenectomy; Siewert type II; Siewert type III.