MAGNIFYING ENDOSCOPIC DIAGNOSIS OF SUPERFICIAL ESOPHAGEAL CANCER∼INTRODUCTION AND EXPLANATION OF THE JAPAN ESOPHAGEAL SOCIETY CLASSIFICATION∼

The diagnosis and prediction of tumor infiltration depth are crucial for selecting the optimal treatment strategy for superficial esophageal cancers. The surface structure and vascular architecture of the tumor change during the development of esophageal squamous neoplasia. These features can thus be used to differentiate cancer from a benign lesion and predict the degree of cancer infiltration. A new endoscopic classification, the Japan Esophageal Society classification, was developed for the diagnosis of esophageal squamous neoplasia. <BR>High-magnification endoscopic diagnosis using this classification is mainly based on the appearance of superficial vascular architecture, especially changes in intrapapillary capillary loops. Cancer was diagnosed when well-demarcated change of the epithelium and vessels demonstrating dilatation, tortuosity, caliber change, and various shapes (four signs) (Type B1 vessels) were identified. An undetermined status was assigned when vessels with one to three of these signs (Type A vessels) were identified. Cancer limited to the epithelium or invading into the lamina propria usually appears as loop vessels demonstrating dilatation, tortuosity, caliber change, various shapes and elongation (Type B1 vessels) or a small avascular area measuring ≤0.5 mm surrounded by vessels (AVA-small). Cancer invading into the muscularis mucosa or the submucosa ≤200 μm usually appears as non-loop vessels demonstrating destruction of loop-like structure of vessels and appearance of thin branch-shaped vessels (Type B2 vessels) or a medium-sized avascular area measuring 0.6-3.0 mm surrounded by non-loop vessels (AVA-middle). Cancer invading into the submucosa >200 μm usually appears as non-loop thick vessels demonstrating destruction of loop-like structure of vessels and appearance of thick non-loop vessels (Type B3 vessels) or a large avascular area >3 mm surrounded by non-loop vessels (AVA-large). Detailed observation of the surface structure and vascular architecture of esophageal neoplasias is thus very important because it can provide valuable information for the diagnosis and prediction of infiltration depth of such tumors. Further development of this classification is warranted based on detailed investigation by members of this society.