A 58-year-old woman from Mumbai presents with a 6-week history of vaginal bleeding and pelvic pain. She is postmenopausal for 8 years. On pelvic examination, there is a 4 cm firm mass in the right adnexa. Transvaginal ultrasound shows a complex ovarian mass with solid and cystic components. Serum CA-125 is 280 U/mL. She undergoes staging laparotomy with total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and peritoneal biopsies. Intraoperative findings show a unilateral ovarian mass confined to the ovary with no ascites, peritoneal involvement, or distant metastases. Histopathology confirms high-grade serous ovarian adenocarcinoma. What is the most appropriate next step in management after surgery?

Explanation

## Adjuvant Chemotherapy in Early-Stage High-Grade Serous Ovarian Cancer **Key Point:** High-grade serous ovarian cancer (HGSOC) is an aggressive histotype with high recurrence risk even at early stage. Adjuvant platinum-taxane chemotherapy is the standard of care for all patients with Stage IC or higher disease, and is strongly recommended even for Stage IA/IB HGSOC. ### Stage and Risk Stratification This patient has **Stage IA disease** (unilateral ovarian mass confined to the ovary, no peritoneal involvement, no ascites). However, the histological grade and type are critical: | Feature | Risk Category | Adjuvant Chemotherapy | |---------|---------------|----------------------| | **Stage IA, Grade 1–2 (low-grade)** | Low risk | Observation or chemotherapy (individualized) | | **Stage IA, Grade 3 (high-grade)** | High risk | **Chemotherapy recommended** | | **Stage IB–IC, any grade** | High risk | **Chemotherapy standard** | | **Stage II or higher** | High risk | **Chemotherapy standard** | **High-Yield:** High-grade serous ovarian cancer has a **5-year recurrence rate of 30–40% even at Stage IA** without adjuvant chemotherapy. Platinum-taxane chemotherapy reduces this risk significantly. ### Chemotherapy Regimen The standard adjuvant regimen for ovarian cancer is: - **Carboplatin** (AUC 5–6) + **Paclitaxel** (175 mg/m²) IV every 3 weeks - **Duration:** 6 cycles (18 weeks total) - **Rationale:** Platinum agents are the backbone; taxanes improve survival in advanced disease and are now standard in early-stage high-grade tumours **Clinical Pearl:** The ICON1 and ACTION trials established that adjuvant chemotherapy improves recurrence-free and overall survival in early-stage ovarian cancer, particularly in high-grade histotypes. For HGSOC, chemotherapy is now considered standard even at Stage IA. **Mnemonic — Adjuvant Chemotherapy Indications:** **"Stage ≥IC or Grade 3 IA"** — Chemotherapy is recommended if the patient has Stage IC or higher disease, OR if she has Stage IA with high-grade (Grade 3) histology. ### Why Other Options Are Incorrect - **Observation alone** is not appropriate for high-grade serous histology, even at Stage IA - **Radiation therapy** has no role in early-stage ovarian cancer management (toxicity outweighs benefit) - **Hormonal therapy** is not used in high-grade serous ovarian cancer (reserved for low-grade serous or clear-cell subtypes) [cite:ICON1 Trial; ACTION Trial; NCCN Ovarian Cancer Guidelines 2023]