Role of surgery in stage IV high-grade serous ovarian cancer: a French population-based multi-center study using Epidemiological Strategy and Medical Economics ovarian cancer database.

OBJECTIVE: To identify clinicobiological factors associated with receipt of surgery in patients with International Federation of Gynecology and Obstetrics 2014 stage IV high-grade serous ovarian carcinoma and to determine prognostic factors for overall survival and progression-free survival among those undergoing cytoreductive surgery. METHODS: This retrospective study used the nationwide French Epidemiological Strategy and Medical Economics ovarian cancer database. Patients with de novo International Federation of Gynecology and Obstetrics stage IVa to IVb high-grade serous ovarian carcinoma who received at least 1 systemic treatment were included. Patients were grouped according to receipt of cytoreductive surgery (primary or interval) or systemic therapy alone. Clinicobiological characteristics were compared using univariate analyses. Survival was estimated with the Kaplan-Meier method, and hazard ratios were derived from Cox models. Multi-variable analyses identified predictors of surgical management and prognostic factors in operated patients. RESULTS: Among 13,032 patients, 729 had de novo stage IV high-grade serous ovarian carcinoma. Cytoreductive surgery was performed in 478 patients (65.6%), predominantly as interval surgery after neoadjuvant chemotherapy (81.8%). Patients who underwent surgery were younger, had better Eastern Cooperative Oncology Group performance status, more frequent BRCA mutations, and fewer metastatic sites. Complete macroscopic resection was achieved in 83.1%. After a median follow-up of 52.2 months, median overall survival was 49.8 months with surgery versus 25.2 months without, and median progression-free survival was 19.2 versus 10.1 months. Among patients who underwent surgery, Eastern Cooperative Oncology Group >1 (hazard ratio 1.70), multiple metastatic sites (hazard ratio 1.48), and incomplete cytoreduction (hazard ratio 1.96) were independently associated with worse overall survival. Surgical timing had no significant impact on overall survival or progression-free survival. CONCLUSIONS: Cytoreductive surgery was associated with longer survival in selected stage IV high-grade serous ovarian carcinoma patients, though baseline differences between patients who underwent surgery and those who did not preclude causal interpretation. Complete resection is the key determinant of benefit, while timing of surgery is not. Careful multi-disciplinary selection remains essential.