Figure 1.

The anatomy and definitions of gastric cancer. (A) Siewert classification classifies tumors into three types: Type I, adenocarcinoma of the distal part of the esophagus—the tumor center is located 1–5 cm above the gastric cardia; Type II, adenocarcinoma of the real cardia—the tumor center is located 1 cm above or 2 cm below the gastric cardia; Type III, adenocarcinoma of the subcardial stomach—the tumor center is located 2–5 cm below the gastric cardia. (B) Nishi's classification defines five types of EGJ cancer featured by diameters of ≤40 mm and an epicenter within 2 cm proximal or distal from the EGJ, irrespective of histological type. The “E–G” terms of “E,” “EG,” “E = G,” “GE,” and “G” are used to describe the subtype according to the epicenter location at the rostral and caudal portions of the EGJ. (C) JGCA classification has divided the stomach into three portions: the upper (U), middle (M), and lower (L) parts, by the lines connecting the trisected points on the lesser and greater curvatures, which had been separately identified as the proximal stomach, gastric corpus, and distal stomach.