Table 1.

FIGO 2023 staging of the endometrium. Adapted from Berek et al. [78]. See Section 5.3 for a detailed explanation. LVSI = lymphovascular space invasion, POLEmut = DNA polymerase epsilon mutated, and p53abn = p53 abnormal.

Stage	Description
Stage 1	Confined to the uterine corpus and ovary
	1A	Disease limited to the endometrium OR non-aggressive histological type, i.e., low-grade endometroid, with invasion of less than half of myometrium with no or focal LVSI OR good prognosis disease. 1A1: Non-aggressive histological type limited to an endometrial polyp OR confined to the endometrium. 1A2: Non-aggressive histological types involving less than half of the myometrium with no or focal LVSI. 1A3: Low-grade endometrioid carcinomas limited to the uterus and ovary.
	1B	Non-aggressive histological types with invasion of half or more of the myometrium, and with no or focal LVSI
	1C	Aggressive histological types limited to a polyp or confined to the endometrium
Stage 2	Invasion of cervical stroma without extrauterine extension OR with substantial LVSI OR aggressive histological types with myometrial invasion
	2A	Invasion of the cervical stroma of non-aggressive histological types
	2B	Substantial LVSI of non-aggressive histological types
	2C	Aggressive histological types with any myometrial involvement
Stage 3	Local and/or regional spread of the tumour of any histological subtype
	3A	Invasion of uterine serosa, adnexa, or both by direct extension or metastasis 3A1 Spread to ovary or fallopian tube (except when meeting stage 1A3 criteria) 3A2 Involvement of uterine subserosa or spread through the uterine serosa
	3B	Metastasis or direct spread to the vagina and/or to the parametria or pelvic peritoneum 3B1 Metastasis or direct spread to the vagina and/or the parametria 3B2 Metastasis to the pelvic peritoneum
	3C	Metastasis to the pelvic or para-aortic lymph nodes or both 3C1 Metastasis to the pelvic lymph nodes (3C1 i—micrometastasis; 3C1 ii—macrometastasis) 3C2 Metastasis to para-aortic lymph nodes up to the renal vessels, with or without metastasis to the pelvic lymph nodes (3C2 i—micrometastasis; 3C2 ii—macrometastasis)
Stage 4	Spread to the bladder mucosa and/or intestinal mucosa and/or distance metastasis
	4A	Invasion of the bladder mucosa and/or the intestinal/bowel mucosa
	4B	Abdominal peritoneal metastasis beyond the pelvis
	4C	Distant metastasis, including metastasis to any extra-or intra-abdominal lymph nodes above the renal vessels, lungs, liver, brain, or bone
Stage	Molecular findings in patients with early endometrial cancer (Stages I and II after surgical staging)
Stage 1AmPOLEm	POLEmut endometrial carcinoma, confined to the uterine corpus or with cervical extension, regardless of the degree of LVSI or histological type
Stage 2Cmp53abn	p53abn endometrial carcinoma, confined to the uterine corpus with any myometrial invasion, with or without cervical invasion, and regardless of the degree of LVSI or histological type