GASTRIC CANCER
Anatomy
-
Stomach begins at GEJ till pylorus
-
Tumour with epicentre >2cm into proximal stomach - considered gastric cancers
-
Tumour involving GEJ with epicentre <2cm into stomach - considered esophageal cancers
-
Endoscopic and pathologic variation of exact GEJ location
Siewert classification
-
Originally - GE junction defined topographically at angle of His
-
Type I - adenocarcinoma of lower oesophagus with epicentre located within 1cm to 5cm above anatomic GEJ
-
Type II - true carcinoma of cardia at GEJ with tumour epicentre within 1cm above and 2cm below GEJ
-
Type III - subcardial carcinoma with tumour epicentre between 2cm to 5cm below the GEJ, which infiltrates GEJ and lower esophagus from below - treated as gastric cancers
Nishi classification
-
Limits definition of GE junction to 2cm proximal and distal to angle of His
Blood supply of stomach
-
Left gastric artery from celiac artery
-
Right gastric artery from common hepatic artery
-
Left gastroepiploic artery from splenic artery
-
Right gastroepiploic artery from gastroduodenal artery
-
Short gastric arteries from splenic artery
-
Posterior gastric artery from splenic artery
-
Arterial variations can occur
-
Rich submucosal blood supply
-
Venous drainage parallels arterial supply - drains into portal venous system