Esophageal cancer is ranked among the top 10 most common cancers in the world, with more than 480,000 new cases diagnosed annually.1 The proportion of cases involving the two most common histopathologic entities, adenocarcinoma and squamous cell carcinoma, is changing. While the incidence of adenocarcinoma of the esophagus is rising rapidly in Western countries, that of squamous cell carcinoma remains unchanged.2 The true incidence of adenocarcinoma is difficult to determine because cancer of the esophagogastric junction (EGJ) is classified by some as a gastric cancer and by others as an esophageal cancer (see Chapter 12). This explains, in part, the ongoing controversy over which strategy to follow when it comes to surgical approach and technique.
In an effort to rationalize what had been a rather indiscriminate approach to EGJ tumors and to provide clearer guidelines, in 1998, Siewert and Stein3 published a classification for adenocarcinoma of the esophagogastric junction (AEG). AEG tumors were defined as tumors with an epicenter equal to or less than 5 cm proximal and distal to the anatomic EGJ (anatomic cardia).
Three entities were distinguished:
Adenocarcinoma of the distal esophagus, usually arising in Barrett intestinal metaplasia,
True carcinoma of the EGJ, which may arise from the cardiac epithelium or from Barrett intestinal metaplasia, and
Subcardial adenocarcinoma arising from the gastric fundus.
Using this classification and drawing on their own data, Siewert and Stein proposed guidelines on which surgical strategy to use according to each of the above-described subtypes. This classification is based entirely on identifying the “anatomic” cardia and measuring the center of the tumor in relation to this anatomic cardia on the resected specimen (i.e., pathologic staging). However, measuring the center of the tumor turns out to be impractical if not impossible for the purposes of clinical staging. It is important to have accurate clinical staging because it ensures the appropriateness of the therapeutic decision (e.g., in the presence of a hiatal hernia). Not surprisingly, Omloo et al.4 reported a substantial discrepancy between the clinical and pathologic staging when using the Siewert classification.
The 7th edition of the TNM classification system,5 which was based on evidence derived from a large international multinational database, also addressed this issue. It classified and staged tumors that have their epicenter in the EGJ, or within the proximal 5 cm of the stomach and extending into the EGJ or esophagus, similarly to an adenocarcinoma of the esophagus. Tumors centered in the stomach that are located more than 5 cm from the EGJ, or tumors within 5 cm of the EGJ but without extension into the esophagus, were classified and staged as gastric tumors.6
In the 8th edition of the TNM classification, consensus review by the Upper GI Expert Panel of the EGJ led to a change in the definition (Fig. 13-1). Cancers with epicenter no ...