Optimal Extent of Lymph Node Dissection for Siewert Type II Esophagogastric Junction Carcinoma

OBJECTIVE: To determine the optimal extent of lymph node dissection for carcinomas of the true cardia, otherwise called Siewert type II esophagogastric junction (EGJ) carcinomas. BACKGROUND: In patients with cancer of the EGJ, comparable outcomes have been obtained with extended esophagectomy and total gastrectomy. The issue of the optimal surgical approach for EGJ tumors has been under debate. Nodal involvement is a strong predictor of survival, however, the optimal extent of prophylactic lymphadenectomy for Siewert type II tumors remains to be elucidated. METHODS: We retrospectively evaluated the distributions of the metastatic nodes, the recurrence pattern, and the oncological outcomes in a single-center large cohort of 225 patients with Siewert type II tumors. To assess the therapeutic outcomes of respective node dissection, we applied an index calculated by multiplication of the incidence of metastasis by the 5-year survival rate of patients with metastasis in the respective node stations. RESULTS: The incidence of nodal metastasis was high in the right paracardial (38.2%), lesser curve (35.1%) and left paracardial (23.1%) nodes, and also the nodes along the left gastric artery (20.9%). Involvement of the suprapancreatic nodes along the celiac artery, splenic artery and common hepatic artery was found in 23, 25, and 14 patients, respectively. According to the index of estimated benefit from lymph node dissection, dissection of the paracardial and lesser curve nodes yielded the highest therapeutic benefit. The number of metastatic nodes in these areas was as predictive of the disease-free and overall survivals as the TNM pN category. The 5-year overall survival rates in patients with no or 1-2 metastatic nodes were 76.6% and 62.3%, respectively, whereas the 5-year survival rate in those with 3 or more positive nodes was only 22.4%, comparable with the rate of 17.4% in patients with TNM pN3 tumors. CONCLUSIONS: Clear anatomic distinction of EGJ tumors is likely to provide insight into the appropriate extent of lymphadenectomy. Dissection of the paracardial and lesser curve nodes is essential for staging as well as for obtaining therapeutic benefit in surgery for in EGJ carcinomas (Siewert type II).