Prognostic factors in patients with stage III-IV high-grade serous ovarian cancer (HGSOC) following complete resection/ R0: FIGO stage, PCI, Fagotti score, HR status

Background: Advanced-stage high grade serous ovarian cancer (HGSOC) is a highly aggressive malignancy, often diagnosed at a late stage and associated with poor prognosis. Several preoperative factors are widely used to assess tumor burden and the likelihood of complete cytoreduction. Achieving no residual disease after surgery (R0) remains the most important predictor of survival. To address treatment decisions, postoperative management and personalized therapies, there is a need to identify additional prognostic factors beyond R0. Aim of the study: This study aims to evaluate the prognostic significance of clinical, surgical, and molecular factors in patients with advanced stage high-grade serous ovarian cancer (HGSOC) who underwent primary debulking surgery (PDS), and achieved complete cytoreduction (R0). Specifically, it investigates the association between FIGO stage, Peritoneal Cancer Index (PCI), Fagotti score, Homologous Recombination (HR) status, and survival outcomes, in order to improve risk stratification. Materials and methods: This retrospective study included patients diagnosed with advanced stage HGSOC who underwent PDS at the University of Padua Hospital between May 2019 and March 2025. Clinical, surgical (PCI, Fagotti score), pathological, and molecular (BRCA mutation status, HR status) data were collected. All patients received adjuvant chemotherapy and structured follow-up. Survival outcomes were analyzed using Kaplan-Meier curves and appropriate statistical tests (p < 0.05). Results: A total of 75 patients with advanced stage HGSOC who achieved complete cytoreduction (R0) during primary debulking surgery were included. Among preoperative factors, both a low Fagotti score (< 8) and a low PCI (≤ 16) were significantly associated with improved overall survival (p = 0.01 and p = 0.049, respectively), while HRD/BRCA-mutated status showed a significant correlation with longer progression-free survival (p = 0.078). FIGO stage had a significant association with progression-free survival (p = 0.049), with more advanced stages correlating with shorter PFS, although its impact on overall survival was less evident. Conclusion: Even following complete cytoreduction, selected preoperative parameters retain prognostic importance. In particular, Fagotti score, PCI, HR status and FIGO stage demonstrated potential value in optimizing postoperative risk stratification. These findings support the integration of preoperative tumor burden and molecular profiling in the postoperative setting, to personalize follow-up strategies and guide therapeutic decisions.