Ovarian Involvement in Endometrial Cancer is Stage IIIA
In endometrial carcinoma, involvement of the ovary (adnexa) is classified as FIGO Stage IIIA according to the current 2009 staging system. 1, 2
FIGO Staging Framework for Ovarian Involvement
The International Federation of Gynecology and Obstetrics (FIGO) 2009 staging system, which remains the current standard for endometrial cancer, specifically defines Stage IIIA as tumors invading the serosa of the corpus uteri and/or adnexa (which includes the ovaries). 1, 2
Key Staging Definitions:
- Stage I: Tumor confined to the uterine corpus with varying degrees of myometrial invasion 1
- Stage II: Tumor invading cervical stroma but not extending beyond the uterus 1
- Stage IIIA: Tumor invading the serosa and/or adnexa (ovaries/fallopian tubes) 1, 2
- Stage IIIB: Vaginal and/or parametrial involvement 1
- Stage IIIC: Metastasis to pelvic (IIIC1) or para-aortic (IIIC2) lymph nodes 1, 2
Important Clinical Distinctions Within Stage IIIA
Recent evidence demonstrates that not all Stage IIIA disease has equivalent prognosis—the specific pattern of involvement matters significantly for outcomes. 3
Prognostic Differences:
- Adnexal-only involvement: 5-year progression-free survival of 80% and overall survival of 85% 3
- Serosal-only involvement: 5-year progression-free survival of 61% and overall survival of 70% 3
- Combined adnexal/serosal involvement: 5-year progression-free survival of 33% and overall survival of 60% 3
Multivariate analysis shows that serosal involvement (with or without adnexal involvement) carries significantly worse prognosis with an adjusted hazard ratio of 2.2 for recurrence compared to adnexal-only disease. 3
Critical Caveat: Synchronous Endometrial-Ovarian Tumors
A major pitfall is distinguishing true metastatic disease (Stage IIIA) from synchronous independent primary tumors (which would be staged separately). 4
When to Consider Synchronous Primaries vs. Metastatic Disease:
- Traditional criteria for synchronous primaries: Both tumors are endometrioid, well-differentiated (grade 1), with no or minimal myometrial invasion, no lymphovascular space invasion, and no other metastatic disease 4
- However, molecular evidence increasingly suggests that most simultaneously occurring endometrioid carcinomas of the endometrium and ovary are actually clonal (metastatic) rather than independent primaries, challenging traditional assumptions 4
- Stage IA3 designation: The 2023 FIGO update specifically created Stage IA3 for low-grade endometrioid carcinomas limited to the uterus with simultaneous low-grade endometrioid ovarian involvement, recognizing this unique scenario 5
Surgical Staging Requirements
Complete surgical staging for suspected Stage IIIA disease must include: 1, 6
- Total hysterectomy with bilateral salpingo-oophorectomy
- Peritoneal washings/cytology
- Thorough abdominal exploration
- Pelvic and para-aortic lymph node assessment
- Assessment of depth of myometrial invasion
- Documentation of serosal and adnexal involvement
Treatment Implications
For confirmed Stage IIIA disease with ovarian involvement: 1
- Maximal surgical cytoreduction is recommended for patients with good performance status 1
- Adjuvant chemotherapy with platinum-based regimens (carboplatin/paclitaxel or cisplatin/doxorubicin) is standard, as it significantly improves progression-free and overall survival compared to radiation alone 1
- Pelvic radiotherapy may be added to increase locoregional control 1