Abstract P5-12-17: Prognostic and predictive value of serum level of vascular endothelial growth factor-A in metastatic breast cancer patients treated with bevacizumab plus paclitaxel

Abstract

Abstract Background Several studies showed that first-line bevacizumab plus chemotherapy for HER2-negative metastatic breast cancer improves progression-free survival and tumor response rate but not overall survival. MERiDiAN trial evaluated plasma vascular endothelial growth factor-A (VEGF-A) prospectively as a predictive biomarker for bevacizumab efficacy in metastatic breast cancer. However, results of this trial do not support using baseline plasma VEGF-A to identify patients benefitting most from bevacizumab. We measured baseline serum VEGF-A level from stored blood samples of metastatic breast cancer patient with treated bevacizumab plus paclitaxel as fist-line and later line therapy, and evaluated a correlation between serum VEGF-A level and efficacy of bevacizumab and prognosis of breast cancer patients tread with bevacizumab, retrospectively. Patients and methods We examined blood samples from 57 metastatic breast cancer patients treated with bevacizumab and paclitaxel, after obtaining written informed consent. And, we evaluated a correlation between baseline serum VEGF-A level and time to treatment failure (TTF) and overall survival (OS). We also compared the serum VEGF-A level of response group (CR and PR) and that of non-response group (SD and PD). Results Baseline serum level of VEGF-A ranged from 80 to 2079 pg/ml. Cases of treatment line were as follows: first-line, 22 cases (38.6%); second line, 11 cases (19.3%) and third-line and the later line, 24 cases (42.1%). The cutoff identified by ROC curve analysis that was able to differentiate response group and non-response group in first-line setting was 360pg/ml for serum VEGF-A. And, we separated high serum VGEF-A group and low serum VEGF-A group of patients treated with bevacizumab plus paclitaxel. In patients treated as first line therapy, median TTF was 4.0 months with high serum VGEF-A group versus 5.0 months with low serum VEGF-A group, and median OS was 12 months with high serum VGEF-A group versus 11months with low serum VEGF-A group. There were no significant differences in both TTF and OS in first line setting. In patients treated as second line and later line therapy, median TTF was 2.8 months with high serum VGEF-A group versus 7.1 months with low serum VEGF-A group, and median OS was 6.4 months with high serum VGEF-A group versus 12.7 months with low serum VEGF-A group. The prognosis of high serum VEGF-A group was significantly worse than that of low serum group in both TTF and OS. The serum VEGF-A level of response group was tend to be higher than that of non-response group in first line setting, and was lower in second and later line setting. However, there were no significant differences. Conclusion In this study, serum VEGF-A cannot be a predictor for efficacy of bevacizumab plus paclitaxel as first line therapy for metastatic breast cancer patients. On the other hand, there was a possibility that high serum level of VEGF-A can be a poor prognostic factor in late line therapy setting of bevacizumab. Citation Format: Tozuka K, Nagai SE, Matsumoto H, Hayashi Y, Kubo K, Tsuboi M, Sato A, Takai K, Wang X, Yamada Y, Inoue K. Prognostic and predictive value of serum level of vascular endothelial growth factor-A in metastatic breast cancer patients treated with bevacizumab plus paclitaxel [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-17.