Endoscopic submucosal dissection for undifferentiated-type early gastric cancer: Do we have enough data to support this?

Table 1 Curability for endoscopic resection of early gastric cancer

Curability criteria
Curative resection	En bloc resection, no lateral and vertical margin positivity, no lymphovascular invasion
	Intramucosal cancer, differentiated histology, size ≤ 20 mm, No ulcerative finding
Curative resection for expanded indications	En bloc resection, no lateral and vertical margin positivity, no lymphovascular invasion
	Intramucosal cancer, differentiated histology, size > 20 mm, no ulcerative finding
	Intramucosal cancer, differentiated histology, size ≤ 30 mm, presence of ulcerative finding
	SM 1 depth of invasion, differentiated histology, size ≤ 30 mm, no ulcerative finding
	Intramucosal cancer, undifferentiated histology, size ≤ 20 mm, no ulcerative finding
Non-curative resection	Any resection that does not satisfy one of the above criteria

SM: Submucosa.