Diagnosis of boundary in early gastric cancer.

Endoscopic submucosal dissection (ESD) is an advanced therapeutic endoscopic technique, which allowsresection of larger superficial tumors in the esophagus, stomach, and colon. Precise diagnosis of the boundary between tumor and the non-tumorous surrounding portion is especially important before starting ESD, because too much resection can potentially take more time and can induce a higher complication rate, while too little resection can result in a non-curative resection. The boundary diagnosis is often difficult for early gastric cancer, mainly because of the underlying condition of chronic gastritis. Due to recent developments in endoscopy, including magnified endoscopy and narrow band endoscopy, the boundary diagnosis is becoming easy and more accurate.We have also applied magnified endoscopy combined with narrow band imaging to fresh specimens immediately after resection using thetiling method and XY stage.