Measurements of adiposity as clinical biomarkers for first-line bevacizumab-based chemotherapy in epithelial ovarian cancer

Abstract

ObjectiveThere is a lack of reliable indicators to predict who will benefit most from anti-angiogenic therapy, such as bevacizumab. Recognizing obesity is associated with increased levels of VEGF, the main target of bevacizumab, we sought to assess if adiposity, measured in terms of BMI, subcutaneous fat area (SFA), and visceral fat area (VFA) was prognostic. MethodsReviewed 46 patients with advanced EOC who received primary treatment with bevacizumab-based chemotherapy (N=21) or chemotherapy alone (N=25) for whom complete records, CT prior to the first cycle of chemo, and serum were available. CT was used to measure SFA and VFA by radiologists blinded to outcomes. ELISA was used to measure serum levels of VEGF and angiopoietin-2 in the bevacizumab group. ResultsBMI, SFA, and VFA were dichotomized using the median and categorized as “high” or “low”. In the bevacizumab group median PFS was shorter for patients with high BMI (9.8 vs. 24.7months, p=0.03), while in the chemotherapy group median PFS was similar between high and low BMI (17.6 vs. 11.9months, p=0.19). In the bevacizumab group patients with a high BMI had higher median levels of VEGF and angiopoietin-2, 371.9 vs. 191.4pg/ml (p=0.05) and 45.9 vs. 16.6pg/ml (p=0.09) respectively. On multivariate analysis neither BMI, SFA, nor VFA were associated with PFS (p=0.13, p=0.86, p=0.16 respectively) or OS (p=0.14, p=0.93, p=0.28 respectively) in the chemotherapy group. However, in the bevacizumab group BMI was significantly associated with PFS (p=0.02); accounting for confounders adjusted HR for high vs. low BMI was 5.16 (95% CI 1.31–20.24). Additionally in the bevacizumab group SFA was significantly associated with OS (p=0.03); accounting for confounders adjusted HR for high vs. low SFA was 3.58 (95% CI 1.12–11.43). ConclusionResults provide the first evidence in EOC that patients with high levels of adiposity may not derive benefit from bevacizumab and that measurements of adiposity are likely to be a useful biomarker.