[Esophagogastric junction cancer in the TNM classification]

The current 7th version of the TNM classification newly defines esophagogastric junction cancer as cancer invading the junction, of which the epicenter is located within 5cm proximal or distal to the junction. Progression of tumors is newly staged in this version of the TNM classification by separating adenocarcinoma and squamous cell carcinoma. The background to this revision was to resolve the confusion that occurred when classification of cancer of the esophagus or stomach was left to the judgment of the physician in the 6th version, to acknowledge that the prognosis of gastric cancer patients differs depending on tumor location, and to reflect the rapid increase in the incidence of adenocarcinoma of the cardia and lower esophagus in the USA. Siewert classification is reflected in the definition of esophagogastric junction cancer. The new classification appears appropriate for esophageal squamous cell carcinoma and Siewert type I adenocarcinoma, but there is doubt about type II and type III adenocarcinomas. German, Korean, and Japanese surgeons have investigated which classification of esophageal or stomach junction cancer was better for predicting patient prognosis, and the Japanese report demonstrated that its classification as stomach cancer was more appropriate.