A 52-year-old postmenopausal woman from Delhi presents with progressive abdominal distension and mild abdominal pain for 3 months. She reports early satiety and occasional nausea. On examination, she has a palpable abdominal mass and shifting dullness. Pelvic ultrasound reveals a complex ovarian mass (8 cm) with ascites. Serum CA-125 is 450 U/mL (normal <35). CT abdomen shows omental caking and peritoneal nodules. She undergoes staging laparotomy with total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and peritoneal biopsies. Final histopathology confirms high-grade serous ovarian adenocarcinoma with peritoneal involvement. What is the FIGO stage of this patient's disease?

Explanation

## FIGO Staging of Ovarian Cancer — Stage Determination **Key Point:** FIGO 2014 staging for ovarian cancer is based on the extent of tumour spread beyond the ovary. The presence of peritoneal involvement (omental caking, peritoneal nodules) combined with ascites places this patient in Stage III disease. ### Stage III Substratification Stage III is subdivided based on the location and extent of peritoneal involvement: | Stage | Criteria | |-------|----------| | **IIIA** | Microscopic peritoneal involvement beyond the pelvis (positive peritoneal washings or biopsies) | | **IIIB** | Macroscopic peritoneal involvement ≤2 cm in greatest dimension | | **IIIC** | Macroscopic peritoneal involvement >2 cm AND/OR positive retroperitoneal lymph nodes | | **IVA** | Pleural effusion with positive cytology | | **IVB** | Distant metastases (liver parenchyma, brain, bone, etc.) | ### Why This Patient Is Stage IIIC This patient has: 1. **Omental caking** — macroscopic peritoneal involvement (omentum is peritoneal tissue) 2. **Peritoneal nodules** — additional macroscopic disease >2 cm in aggregate 3. **No distant metastases** — excludes Stage IV 4. **No pleural involvement** — excludes Stage IVA **High-Yield:** Ascites alone does NOT change staging; it is the presence of **macroscopic peritoneal deposits >2 cm** that defines Stage IIIC. Omental involvement is considered peritoneal spread and is a hallmark of advanced ovarian cancer. **Clinical Pearl:** In ovarian cancer, peritoneal involvement is more common than distant metastases. Stage IIIC disease is the most common presentation at diagnosis, accounting for approximately 40% of epithelial ovarian cancers. **Mnemonic — FIGO III vs IV:** **"Peritoneal = III, Pleural/Parenchymal = IV"** — If disease is confined to the peritoneal cavity (even with omental caking), it remains Stage III. Only when it crosses into the pleura (IVA) or distant organs (IVB) does it become Stage IV. [cite:Colombo et al. FIGO 2014 Ovarian Cancer Staging]