Correlation of bevacizumab relative dose intensity with first-line treatment outcomes in advanced epithelial ovarian cancer

OBJECTIVE: To evaluate the association between bevacizumab relative dose intensity (RDI) and first-line treatment outcomes in advanced epithelial ovarian cancer. METHODS: We retrospectively analyzed 72 patients treated with first-line bevacizumab plus paclitaxel-platinum chemotherapy between January 2019 and September 2024. Patients were categorized using X-tile-derived RDI cutoffs as low (≤0.61), intermediate (>0.61 to <0.93), or high (≥0.93). Objective response rate (ORR), progression-free survival (PFS), and adverse events were compared, and Cox proportional hazards regression was used to assess factors associated with PFS. RESULTS: ORRs were 40.0%, 75.0%, and 80.0% in the low-, intermediate-, and high-RDI groups, respectively (p=0.011). Median PFS was 12.6, 21.2, and 23.5 months, respectively (log-rank p=0.037), with the greatest difference between the low- and high-RDI groups (p=0.018). In multivariable analysis, high versus low RDI was associated with a lower risk of progression (hazard ratio=0.463; 95% confidence interval=0.235-0.913; p=0.026). Overall adverse-event incidence did not differ significantly among groups; however, grade 3-4 neutropenia and thromboembolic events were significantly more frequent in the high- than low-RDI group. CONCLUSION: Lower bevacizumab RDI was associated with poorer response and shorter PFS. Given the retrospective single-center design, the optimal RDI threshold requires validation in larger prospective studies.