Abstract
To treat early gastric cancer, one must choose between endoscopic treatment and surgical treatment. Endoscopic treatment has been developing significantly since the late 1990s and has made great progress up to the present. However, many patients with early gastric cancer still undergo unnecessary surgery or endoscopic procedures. This is due to the existence of a "gray zone" of ambiguities between endoscopic and surgical treatment. These ambiguities arise because the important factors in determining the treatment for early gastric cancer can only be fully understood after endoscopic or surgical resection or because of discrepancies between the factors identifiable before treatment and those identifiable after treatment. This article aims to explore these ambiguous factors and discuss methods and efforts to reduce them.