The Chinese Society of Clinical Oncology (CSCO): Clinical guidelines for the diagnosis and treatment of gastric cancer, 2023

. 2023 Dec 31;44(1):127–172. doi: 10.1002/cac2.12516

Tumor depth	Ulcer	Differentiated		Undifferentiated
pT_1a (M)	0	<2cm^*^,^†	>2cm^*^,^†	<2cm^*^,^†	>2cm ^※
pT_1a (M)	1	<3cm^*^,^†	>3cm ^※
pT_1b (SM 1)		<3cm^*^,^†	>3cm ^※

Abbreviations: eCura, endoscopic curative resection; SM1, submucosal infiltration depth <500μm.

Complete resection, negative margins, and no lymphovascular invasion.

^{^†}

eCura A; ^‡, eCura B, ^※, eCura C‐2.

eCura C‐1 refers to either eCura A or B but with positive lateral margins or block resection.

Of note, when the tumor is limited to the mucosa (T1a), it can be represented as M. When the tumor involves the submucosal shallow layer, it is represented as T1b ‐ SM1, with submucosal infiltration depth <500μm.