Survival Impact of Bevacizumab According to Chemotherapy Response Score in Advanced High-Grade Serous Ovarian Carcinoma Treated with Neoadjuvant Chemotherapy.

INTRODUCTION: Chemotherapy response score (CRS) is a prognostic marker in high-grade serous ovarian carcinoma treated with neoadjuvant chemotherapy (NACT). This study evaluated whether the survival benefit associated with sustained bevacizumab exposure differs according to CRS group. METHODS: We retrospectively evaluated patients who underwent interval debulking surgery after platinum-taxane-based NACT between January 2015 and February 2025. Sustained bevacizumab exposure was defined as receipt of more than three cycles. Overall survival (OS) and OS after first recurrence (OS-FR) were assessed using Kaplan-Meier and Cox regression analyses. RESULTS: The cohort included 113 patients: 30 with sustained bevacizumab exposure and 83 in the comparison group; 74 had CRS 1-2 and 39 had CRS 3. Sustained bevacizumab was associated with longer median OS in the overall cohort (57.4 vs. 50.3 months; p = 0.021) and in patients with CRS 1-2 (57.1 vs. 43.6 months; p = 0.045), but not in those with CRS 3 (p = 0.224). OS-FR was also longer with sustained bevacizumab overall (35.0 vs. 23.0 months; p = 0.013) and in CRS 1-2 (35.0 vs. 23.0 months; p = 0.041). In multivariable analysis, sustained bevacizumab was independently associated with improved OS-FR (landmark-corrected HR 0.23, 95% CI 0.07-0.75; p = 0.015). CONCLUSIONS: Sustained bevacizumab exposure was associated with longer OS and OS-FR, particularly in patients with CRS 1-2. CRS may help identify patients most likely to benefit from bevacizumab, although these findings require prospective validation.