Radiation Oncology/Endometrium/Staging

Current staging

Endometrial Carcinomas

FIGO Staging (2023)

PMID 37593813 -- "FIGO staging of endometrial cancer: 2023"

• Stage I - Confined to the uterine corpus and ovary
  • IA - 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
    • IA1 : Non-aggressive histological type limited to an endometrial polyp OR confined to the endometrium
    • IA2 : Non-aggressive histological types involving less than half of the myometrium with no or focal LVSI
    • IA3 : Low-grade endometrioid carcinomas limited to the uterus and ovary
  • IB - Non-aggressive histological types with invasion of half or more of the myometrium, and with no or focal LVSI
  • IC - Aggressive histological types limited to a polyp or confined to the endometrium
• Stage II - Invasion of cervical stroma without extrauterine extension OR with substantial LVSI OR aggressive histological types with myometrial invasion
  • IIA - Invasion of the cervical stroma of non-aggressive histological types
  • IIB - Substantial LVSI of non-aggressive histological types
  • IIC - Aggressive histological types with any myometrial involvement
• Stage III - Local and/or regional spread of the tumor of any histological subtype
  • IIIA - Invasion of uterine serosa, adnexa, or both by direct extension or metastasis
    • IIIA1 : Spread to ovary or fallopian tube (except when meeting stage IA3 criteria)
    • IIIA2 : Involvement of uterine subserosa or spread through the uterine serosa
  • IIIB - Metastasis or direct spread to the vagina and/or to the parametria or pelvic peritoneum
    • IIIB1 : Metastasis or direct spread to the vagina and/or the parametria
    • IIIB2 : Metastasis to the pelvic peritoneum
  • IIIC - Metastasis to the pelvic or para-aortic lymph nodes or both
    • IIIC1 : Metastasis to the pelvic lymph nodes {IIIC1i: micrometastasis; IIIC1ii: macrometastasis}
    • IIIC2 : Metastasis to para-aortic lymph nodes up to the renal vessels, with or without metastasis to the pelvic lymph nodes {IIIC2i: micrometastasis; IIIC2ii: macrometastasis}
• Stage IV - Spread to the bladder mucosa and/or intestinal mucosa and/or distant metastasis
  • IVA - Invasion of the bladder mucosa and/or the intestinal/bowel mucosa
  • IVB - Abdominal peritoneal metastasis beyond the pelvis
  • IVC - Distant metastasis, including metastasis to any extra-or intra-abdominal lymph nodes above the renal vessels, lungs, liver, brain, or bone

Staging footnotes:

• Disease limited to low-grade endometrioid carcinomas involving the endometrium and ovaries (Stage IA3) must be distinguished from extensive spread of the endometrial carcinoma to the ovary (Stage IIIA1), by the following criteria: 1) no more than superficial myometrial invasion is present (<50%); 2) absence of extensive/substantial LVSI; 3) absence of additional metastases; and 4) the ovarian tumor is unilateral, limited to the ovary, without capsule invasion/rupture (equivalent to pT1a).
• LVSI: LVSI as defined in WHO 2021: extensive/substantial, ≥5 vessels involved.
• Aggressive histological types:
  • non-aggressive: G1-2 EEC.
  • aggressive: G3 EEC, serous, clear cell, undifferentiated, mixed, mesonephric-like, gastrointestinal mucinous type carcinomas, and carcinosarcomas

AJCC 7th Edition (2009)

Corresponds to updated FIGO staging (2009)

FIGO 2009 PMID 19345353 -- "Revised FIGO staging for carcinoma of the endometrium."

This staging now applies only to endometrial carcinomas and there is now a separate staging for uterine sarcomas.

Carcinosarcomas (MMMT) should be staged as high grade carcinoma.

Primary Tumor: (FIGO Stage in parentheses)

Note: FIGO uses pathologic staging

• Tis - in situ

  Note: FIGO no longer includes Stage 0

• T1 (I) - confined to corpus
  • T1a (IA) - limited to endometrium or invades less than 1/2 of myometrium
  • T1b (IB) - invades ≥ 1/2 of myometrium
• T2 (II) - invades stromal tissue of the cervix but does not extend beyond uterus

  Note: endocervical glandular involvement only should be considered as Stage I not Stage II

• T3
  • T3a (IIIA) - involves serosa and/or adnexa (direct extension or metastasis)
  • T3b (IIIB) - vaginal involvement (direct extension or metastasis) or parametrial involvement
• T4 (IVA) - invades bladder mucosa and/or bowel mucosa

Regional Lymph Nodes:

• N0 - none
• N1 (IIIC1) - metastasis to pelvic lymph nodes
• N2 (IIIC2) - metastasis to para-aortic lymph nodes

  Note: Regional nodes include obturator, internal iliac, external iliac, common iliac, para-aortic, presacral, and parametrial

  Note: For pathologic staging, FIGO classifies cases with <6 resected LNs as pNX

Distant Metastases:

• M0 - none
• M1 (IVB) - distant metastasis - includes inguinal LN, intraperitoneal disease (including omentum), lung, liver, or bone.

Stage Grouping:

• Corresponds to FIGO stage given above (in parentheses)

Changes from 6th Edition:

• No longer includes uterine sarcoma (now staged with a new staging system)
• Positive peritoneal cytology is no longer considered (previously was T3a/IIIA)
• Involvement of the endocervical glands is no longer considered (previously was Stage IIA)
• Stages IA+IB combined (now: IA). IC moved to IB.
• Stage IIIC subdivided into IIIC1 and IIIC2.

Older staging systems

FIGO moved to surgical staging in 1988 (AJCC 6th edition same). There is also a clinical staging system developed by FIGO in 1971.

Note: until the update of the FIGO / AJCC in 2009, uterine sarcomas and carcinomas were staged using the same system

AJCC 6th Edition (2002)

• IA - Limited to endometrium
• IB - < 1/2 of myometrium
• IC - 1/2 or more of myometrium
• II - invades cervix
  • IIA - glandular epithelium of endocervix
  • IIB - stroma of cervix
• III - extra-uterine
  • IIIA - involves serosa and/or adnexa (direct extension or mets) and/or ascites or positive peritoneal washings
  • IIIB - vaginal involvement (direct extension or mets)
  • IIIC - LN+ (pelvic and/or paraaortic)
• IV - other organs
  • IVA - bladder or bowel
  • IVB - distant mets

Clinical staging

Staging is now surgical (see above), but clinical staging may be utilized for non-operative pts.

FIGO 1971

• I - Confined to corpus
  • IA - Length of uterine cavity 8 cm or less
  • IB - Length of uterine cavity > 8 cm
• II - Involves corpus and cervix, but no extension beyond the uterus
• III - Extends outside uterus but not outside true pelvis
• IV - Outside the true pelvis or involves bladder or rectum
  • IVA - Involves bladder, rectum, sigmoid, or small bowel
  • IVB - Distant mets

Stage distribution

Stage Distribution

Stage	US SEER (PMID 16977653)	FIGO (PMID 17161155)
Stage I	73%	67%
Stage II	10%	11%
Stage III	10%	13%
Stage IV	7%	3%