Advanced high-grade serous ovarian cancer treated with intensive cytoreductive surgery and chemotherapy: prognostic impact of lymph node involvement: analysis of the French national ESME-Unicancer database.

Benefits on survival of retroperitoneal lymph node (LN) dissection during cytoreductive surgery (CRS) for epithelial ovarian cancer are debated. However, LN involvement may be a prognostic factor especially in case of high-grade serous ovarian cancer (HGSOC). In the French Epidemiological Strategy and Medical Economics - Ovarian Cancer (ESME-OC) database, we identified patients treated for advanced-stage (FIGO III-IV) HGSOC with chemotherapy and intensive CRS including retroperitoneal LN dissection. Our first objective was to identify prognostic factors in case of maximalist treatment. Of 13032 patients included, 485 with advanced HGSOC diagnosed between May 29, 2006 and December 16, 2019 were analyzed. Primary CRS was performed on 279 patients (57.5%). Of them, 70.3% had LN involvement. Surgery was performed after neo-adjuvant chemotherapy (NAC) in 206 patients (42.5%). Of them, 61.2% had LN involvement. LN involvement was considered major with a Lymph Node Ratio (LNR) ≥25% for 21.1% of patients who underwent primary CRS and 15.0% after NAC. In primary CRS, when adjusted to FIGO stage and BRCA1/2 deleterious mutation, LNR ≥25% vs none indicated a poorer prognosis for both overall survival (OS) (HR = 2.46 [1.25; 4.84], p = 0.009) and progression-free survival (PFS) (HR = 2.23 [1.40; 3.57], p < 0.001). After NAC, LNR ≥25% vs none was a negative prognostic factor with a stronger negative impact on PFS (HR = 2.00 [1.12; 3.57]; p = 0.018). LN involvement is a negative prognostic factor in advanced-stage HGSOC especially in case of primary CRS. LN involvement could be a target for developing new therapies.