Fig. 1

Lymphatic drainage diagram of the stomach according to the first classification of the Japanese Research Society for Gastric Cancer (JRSGC), adapted from [15]. First region: Group 1: Right paracardium Group 2: Left paracardial Group 3: Gastric lesser curvature Group 4: Gastric greater curvature divided into 4sa: short vessels 4sb: Left gastroepiploic artery 4d: Right gastroepiploic artery Group 5: Suprapyloric Group 6: Infrapyloric. Second region: Group 7: Left gastric artery Group 8: Common hepatic artery divided into 8a: Anterior 8p: Posterior Group 9: Celiac trunk Group 10: Splenic hilum Group 11: Splenic artery divided into 11p: Proximal 11d: Distal Group 12: Pedicle of liver divided into 12a: Artery 12b: bile duct 12v: Portal vein. Third region: Group 13: Retropancreatic Group 14: Superior mesenteric artery and vein, divided into 14v: Venous 14a: Arterial Group 15: Middle colic artery Group 16: Paraaortic divided into 16a1: Hiatus of the oesophagus 16a2: From the celiac trunk to the renal vein 16b1: From the renal vein to the inferior mesenteric artery 16b2: From the inferior mesenteric artery to the aortic bifurcation. Groups 19, 20, 110, 111 (which are not shown) correspond to lower mediastinal nodes to be resected in gastric tumours invading the oesophagus and are considered local regional nodes. They are not described in detail here