Endometrial Cancer with Omental Metastasis is FIGO Stage IVB
Endometrial cancer with omental metastasis is classified as FIGO Stage IVB, representing distant metastatic disease with intra-abdominal spread. 1, 2, 1
FIGO Staging Classification
According to the current FIGO staging system (2009/2023), omental involvement falls under Stage IVB disease 1, 2:
- Stage IVB is defined as distant metastases including intra-abdominal metastases and/or inguinal lymph nodes 1
- The omentum is specifically mentioned as an intra-abdominal site that should be inspected and palpated during surgical staging 1
- This classification applies whether the omental metastasis is macroscopic or microscopic 3, 4
Clinical Context and Implications
Prevalence and Detection
- Omental metastases occur in approximately 5.3% of all endometrial cancer cases undergoing complete surgical staging 5
- In clinical stage I disease, microscopic omental metastases are found in 1.9% of patients, accounting for 26.5% of all omental metastases 4
- Isolated omental involvement (omentum as the only extrauterine site) occurs in approximately 0.46% of cases 5
Risk Factors for Omental Metastasis
The following factors are strongly associated with omental involvement 3, 4, 5:
- Positive lymph nodes (RR 8.71) 4
- Adnexal metastases (RR 16.76) 4, 5
- Papillary serous carcinoma histology 3
- Grade 3 tumors 3, 5
- Positive peritoneal cytology 5
Prognostic Significance
- Stage IVB disease with peritoneal/omental metastasis has better survival compared to organ-specific distant metastases (median OS: 29 vs 19 months) 6
- The 5-year overall survival for Stage IVB disease is approximately 23-25% 7
- Patients with omental metastasis should be considered for maximal surgical debulking when feasible 1
Important Clinical Caveats
Microscopic disease is frequently missed: Up to 8.3% of apparent stage I cases have occult omental metastases, with the majority (71%) being microscopic 3. This underscores the importance of routine omental sampling in high-risk cases 3, 4.
Surgical approach matters: Complete surgical staging including omental assessment is essential for accurate staging, as clinical staging results in understaging of 13-22% of patients 2.