Detection and characterization of early gastric cancer for curative endoscopic submucosal dissection

Because endoscopic submucosal dissection (ESD) of gastric cancer can only be curative if the cancer is detected at an early stage and a precise preoperative diagnosis is made, we reviewed the detection and characterization of early gastric cancer (EGC) using both conventional endoscopy with white-light imaging (C-WLI) and image-enhanced endoscopy (chromoendoscopy [CE] and magnifying narrow-band imaging [M-NBI]). Systematic screening of the stomach by C-WLI after ideal preparation of the patient is important for detecting a mucosal lesion, which can then be characterized using CE. However, a limitation of C-WLI with CE is the diagnosis of flat or small gastric cancers. To overcome this, M-NBI together with a comprehensive diagnostic system, termed the 'vessel plus surface classification' system, was developed and has proven very useful. Preoperative assessment for ESD involves determining: (i) histological type; (ii) size; (iii) depth of invasion; (iv) presence or absence of associated ulceration; and (v) horizontal extent of the cancer. A limitation of endoscopic diagnosis using M-NBI is the histologically undifferentiated type of carcinoma, in which case the biopsy specimen is used to make a histopathological diagnosis.