Staging of gastric cancer with endoscopic ultrasonography and endoscopic mucosal resection

Since it was found that the gastrointestinal wall is visualized as a five-layered structure corresponding to the histological layers of the wall, endoscopic ultrasonography (EUS) has become recognized clinically as the most accurate method for diagnosing and assessing the local staging of gastric cancer. However, some problems have remained, including how to differentiate between cancer invasion and ulcer fibrosis, how to detect microinvasion, and how to recognize malignant lymph nodes. Using the pattern analysis for depressed-type gastric cancer, it is usually possible to distinguish between cancer invasion and ulcer fibrosis, except in cases of microinvasion into ulcer fibrosis or inadequate scanning. However, the sensitivity of EUS for evaluating metastatic lymph nodes is still problematic. Endoscopic mucosal resection (EMR) for early gastric cancer has been widely accepted as a standard treatment in Japan due to its minimal invasiveness. According to our data, the overall rate of radical resection was 68.3% (168 of 246), and 31.7% of the remaining patients additionally received laser treatment, surgery, or heater-probe treatment. There were no deaths owing to gastric cancer. Some lesions in which there was microinvasion of the submucosa were incorrectly diagnosed by EUS. It may be possible to solve this problem using three-dimensional EUS (3D-EUS) in the near future.