The Role of Initial Neutropenia and Neutrophil Dynamics in Personalizing Chemotherapy for Platinum-Resistant Ovarian Cancer

<i>Background and Objectives</i>: Platinum-resistant ovarian cancer (PROC) is associated with limited treatment options and poor outcomes, with median progression-free survival (PFS) and overall survival (OS) remaining suboptimal. Neutropenia, a common chemotherapy-related toxicity, has shown potential as a predictive biomarker for treatment efficacy in several malignancies, including ovarian cancer. However, its role as a prognostic marker, particularly baseline neutropenia, remains underexplored. This study aimed to evaluate the prognostic and predictive value of initial neutropenia and neutrophil dynamics in PROC patients undergoing chemotherapy. <i>Materials and Methods</i>: A retrospective cohort study was conducted on 250 PROC patients treated between 2018 and 2022 at the OncoHelp Medical Center, Timișoara, Romania. Patients were stratified into two groups based on baseline absolute neutrophil count (ANC), as those with initial neutropenia (ANC < 2000/mm³) and without initial neutropenia (ANC ≥ 2000/mm³). Clinical outcomes, including tumor response, PFS, and OS, were assessed using RECIST 1.1 criteria. Hematological toxicities and neutrophil dynamics across three chemotherapy cycles were analyzed. <i>Results</i>: Patients with baseline neutropenia demonstrated significantly higher tumor response rates (47.05% vs. 27.27%; <i>p</i> = 0.002), longer median PFS (8.2 vs. 6.3 months; <i>p</i> = 0.008), and extended median OS (14.5 vs. 11.2 months; <i>p</i> = 0.002). Hematological toxicities, including Grade ≥3 neutropenia and febrile neutropenia, were more frequent in the neutropenic group (<i>p</i> < 0.001). Baseline ANC thresholds effectively predicted clinical outcomes, with an AUC of 0.79 for OS. <i>Conclusions</i>: Baseline neutropenia is a significant prognostic marker in PROC, correlating with improved tumor response and survival outcomes despite increased hematological toxicities. These findings support incorporating baseline ANC into treatment personalization strategies for PROC.