Preface. The Siewert Lesson for Adenocarcinomas of the esophagogastric junction: a plea for an order in a complex disease.

Adenocarcinomas of the esophagogastric (AEG) junction show an alarming increase in incidence over the last decades in Western industrialized countries. This special volume with contributions from dedicated individuals and friends in the field tries to summarize our current understanding of the etiology, pathogenesis, classification, clinical staging, and state-of-the-art treatment of this modern plague. In 1987, JR Siewert, Emeritus Professor and Chairman of the Department of Surgery (Fig.) at the Technische Universität München, Germany, inaugurated a therapeutically relevant classification of AEG which is used by many experts and recommended by the International Society for Diseases of the Esophagus and International Gastric Cancer Association. As St. Thomas of Aquino wrote in his Summa contra Gentiles (Book I, Chap. 1): “Those ones have to be called wise who put the things into the right order” (author’s translation). The “Siewert Classification” is purely based on the anatomic localization of the tumor center, which can be defined by endoscopy using the proximal end of the longitudinal gastric mucosa folds as a pragmatic reference for the endoscopic cardia. AEG include all tumors 5 cm proximal (+5 cm) and distal (5 cm) of the endoscopic cardia (point zero). An adenocarcinoma of the distal esophagus (>1 to +5 cm), which usually arises from an area of specialized intestinal metaplasia (Barrett’s esophagus) is classified as a type I cancer. A type II cancer is a true carcinoma of the cardia (+1 to 2 cm) arising at the esophagogastric junction, whereas a type III cancer (2 to 5 cm) is a subcardial gastric carcinoma that infiltrates the esophagogastric junction or the distal esophagus from below. It is noteworthy to mention that the new seventh UICC/AJCC TNM Classification, effective since January 2010, classifies AEG as one group of cancers and finally eliminates meanders like staging regional lymph node metastases at the celiac trunk for Barrett’s cancer as systemic metastases (M1a). Even more important is that the new UICC classification of AEG neither eliminates the Siewert classification nor intends to suggest a change in the surgical approach to treat AEG. For Siewert type I cancers, the standard approach is a transthoracic en bloc esophagectomy with a two-field lymphadenectomy and for the majority of AEG type II and