Survival outcomes of advanced ovarian cancer treated with neoadjuvant chemotherapy versus primary cytoreductive surgery using a quality-assured decision-making approach.

5577 Background: Neoadjuvant chemotherapy (NACT) is recommended for advanced ovarian cancer patients with a low likelihood of achieving complete cytoreduction through primary cytoreductive surgery (PCS) or those with high perioperative risk profiles. The decision between NACT and PCS requires careful evaluation of the feasibility of achieving optimal cytoreduction, emphasizing an individualized approach. This study evaluates whether quality-assured decision-making regarding PCS, based on institutional protocols, improves survival outcomes. Methods: This retrospective study included 1,256 patients diagnosed with FIGO stage IIIB-IVB ovarian, fallopian tube, or primary peritoneal carcinoma who underwent either primary or interval cytoreductive surgery at the National Cancer Center Korea between January 2016 and December 2023. The institutional criteria approach determined NACT eligibility based on patient performance status and/or computed tomography findings indicative of suboptimal cytoreduction. The primary objective was overall survival (OS), while the secondary objective was progression-free survival (PFS). Results: Of 1,256 patients, 666 (53.0%) received NACT followed by ICS, while 590 (47.0%) underwent PCS. Median PFS was significantly longer in the PCS group than in the NACT group (28.6 vs 17 months; HR: 0.63, 95% CI: 0.55–0.73, p < 0.001). Median OS was also longer in the PCS group compared to the NACT group (92.8 vs 62.1 months; HR: 0.61, 95% CI: 0.51–0.74, p < 0.001). Five-year PFS and OS rates were 33.8% and 65.1% in the PCS group vs. 18.3% and 51.3% in the NACT group, respectively. Complete resection of macroscopic disease was achieved in 70.7% of patients overall, with comparable rates between the two groups (p = 0.1). Conclusions: PCS demonstrates superior OS and PFS compared to ICS following NACT in advanced ovarian cancer patients, underscoring its critical role within an individualized decision-making approach. Summary of key outcomes. Outcome PCS (n = 590) NACT + ICS (n = 666) p-value Hazard Ratio (HR, 95% CI) Median PFS (months) 28.6 (24.2–31.7) 17.0 (16.1–18.6) < 0.001 0.63 (0.55–0.73) Median OS (months) 92.8 (89.1–NR) 62.1 (53.8–67.9) < 0.001 0.61 (0.51–0.74) 5-year PFS rate (%) 33.8% 18.3% - - 5-year OS rate (%) 65.1% 51.3% - - Complete Resection (%) 70.7% 70.7% 0.1 -