Should adenocarcinoma of the esophagogastric junction should be classified as esophageal cancer? -- Comparative analysis according to the seventh AJCC TNM classification -

Abstract

Introduction: The seventh AJCC TNM classification proposed the new classification for AEJ as a part of esophageal cancer depending on the esophagogastric junction (EGJ) involvement. However there are still many controversies over the classification system for AEJ. The aim of this study was to evaluate the adequacy of esophageal classification for adenocarcinoma of the esophagogastric junction (AEJ) of the seventh AJCC TNM classification. Methods: A review of pathologic reports and photographic findings at Seoul National University Hospital from 2003 to 2009 identified 4,524 patients with single, primary adenocarcinoma of the EGJ (n=497) and other regions of the stomach (GC, n=4,027) who underwent an operation with curative intent. We analyzed the clinicopathologic features and postoperative prognosis of AEJ using the Siewert classification and the seventh AJCC TNM classification. Results: There was no Siewert type I (AEJ I) in this study. The prognosis of AEJ was similar to that of GC. There was no difference in clinicopathologic features between AEJ II and AEJ III. Even though AEJ extending into the EGJ (AEJe) showed more advanced pathologic features than AEJ not extending into the EGJ (AEJg), the prognosis of AEJe and AEJg was not significantly different when stratified by T stage. Compared with the classification of gastric cancer applied for AEJ, esophageal classification for AEJ from the seventh AJCC TNM classification showed a loss of distinctiveness at each TNM stage. Conclusions: To evaluate the postoperative prognosis of AEJ within the stomach, AEJ II and AEJ III should be considered as a part of gastric cancer irrespective of EGJ involvement.