The optimal extent of lymph node dissection for adenocarcinoma of the esophagogastric junction differs between Siewert type II and Siewert type III patients

The incidence of adenocarcinoma of the esophagogastric junction (AEG) has been increasing worldwide. We investigated the clinicopathological characteristics of patients with Siewert type II and III AEGs and clarified the optimal intra-abdominal lymph node dissection in these patients. This study included 132 patients with AEG who underwent curative resection at Shizuoka Cancer Center from September 2002 to December 2012. We used the index of estimated benefit from lymph node dissection (IEBLD) to assess the efficacy of lymph node dissection of each station. The clinicopathological characteristics and IEBLDs of each station were compared between patients with Siewert type II and III AEGs. We analyzed 92 patients with Siewert type II AEG and 40 patients with Siewert type III AEG. The incidence of lymph node metastasis was high in both groups (64.1 % in type II AEG and 75.0 % in type III AEG). The 5-year survival rates were similar for the patients with Siewert type II and III AEGs, at 54.0 and 53.4 %, respectively. The IEBLDs of stations located near the esophagogastric junction were generally high in both groups, while the IEBLDs of lower perigastric lymph nodes were higher in Siewert type III than in Siewert type II AEG cases. The IEBLDs were similar between Siewert type II and III AEGs at all stations except for lower perigastric lymph nodes. Total gastrectomy should be selected as a standard treatment for Siewert type III AEG, whereas in Siewert type II AEG, preservation of the distal part of the stomach may be an acceptable procedure.