Stage IVC Does Not Exist in the Current FIGO Ovarian Cancer Staging System
There is no stage IVC in the FIGO 2023 staging system for epithelial ovarian cancer—stage IV is divided only into stages IVA and IVB. 1
FIGO Stage IV Classification
The current FIGO staging system for ovarian cancer divides stage IV disease into two distinct categories based on the location and type of distant metastases:
Stage IVA
- Pleural effusion with positive cytology 1
- This represents malignant cells documented in pleural fluid
Stage IVB
- Parenchymal metastases (invasion into solid organs like liver or spleen tissue, not just surface involvement) 1
- Metastases to extra-abdominal organs 1
- Inguinal lymph nodes 1
- Lymph nodes outside the abdominal cavity 1
Important Distinction from Stage III
Stage IIIC includes extension of tumor to the capsule of liver and spleen without parenchymal involvement, whereas stage IVB requires actual invasion into the organ parenchyma. 1 This distinction is critical for accurate staging and has prognostic implications.
Clinical Implications of the Two-Stage Division
The division of stage IV into only IVA and IVB (not IVC) reflects distinct prognostic groups, though research shows conflicting data about which substage has worse outcomes:
One multicenter study (2023) found stage IVA patients had worse prognosis than IVB, with median overall survival of 31 months versus 45 months (p=0.02), suggesting pleural involvement may be particularly aggressive. 2
Conversely, the EORTC 55971 trial analysis (2018) found stage IVB patients had better overall survival (31 months) compared to IVA (24 months, p=0.044), and IVB patients appeared to benefit more from neoadjuvant chemotherapy. 3
These contradictory findings highlight ongoing debate about the prognostic value of the IVA/IVB subdivision, but the staging system remains limited to these two categories without further subdivision. 2, 3