Clinical Efficacy of Endoscopic Submucosal Dissection for Adenocarcinomas of the Esophagogastric Junction

BACKGROUND Adenocarcinoma of the esophagogastric junction (EGJ) is uncommon in Eastern countries, including Japan, but it is believed that the incidence of EGJ adenocarcinoma will increase in Asia in the future due to the decreasing incidence of Helicobacter pylori infection. Endoscopic submucosal dissection (ESD) is a minimally invasive and curative treatment that allows precise pathological assessment. SUMMARY Magnifying endoscopy with narrow-band imaging may be useful for differential diagnoses and for delineating the cancer margin of EGJ adenocarcinoma, but subsquamous carcinoma extension, which is the invasion of EGJ adenocarcinoma beneath the normal esophageal squamous epithelium, makes it difficult to detect cancer margins of the oral side in ESD for EGJ adenocarcinoma. Since subsquamous carcinoma extension was reported to be less than 1 cm in most cases, the oral safety margin that is placed 1 cm from the squamocolumnar junction is useful for negative cancerous horizontal margin. A multicenter retrospective study of esophageal adenocarcinoma including EGJ adenocarcinoma showed that mucosal and submucosal cancer within 500 μm from the muscularis mucosa without lymphovascular involvement, a poorly differentiated component, and lesion size over 3 cm were not associated with metastasis. Several retrospective studies about ESD for EGJ adenocarcinoma have suggested feasible short-term and long-term outcomes using curative criteria based on gastric cancer guidelines. Key Messages: ESD would be a good first-line treatment for superficial EGJ adenocarcinoma, including Barrett's adenocarcinoma. Additional information about the incidence of metastasis would help confirm the indication of ESD for EGJ adenocarcinoma.