Vascular endothelial growth factor activity after switching of bisphosphonate treatment for metastatic breast cancer

Abstract

Background:Recent data have shown a fall in vascular endothelial growth factor (VEGF) concentrations after bisphosphonate (BP) treatment in BP-naïve patients. It has therefore been proposed that BPs may have in vivo anti-VEGF effects.Aims:To explore whether VEGF concentrations change after administration of a more potent BP in patients receiving long-term BP treatment.Methods:31 patients with breast cancer who had progressive metastatic bone disease despite treatment with early-generation BPs were switched to zoledronic acid. Serum VEGF concentrations were measured at baseline, and weeks 1, 2, 3, 4, 8 and 12.Results:VEGF concentration per platelet count did not change significantly at any time during the 12 weeks after treatment with zoledronic acid.Conclusions:Switching to zoledronic acid did not suppress circulating serum VEGF concentrations in BP-pretreated patients. Novel approaches to assess the effect of BPs on the bone milieu may provide further insight into the possible antiangiogenic properties of BPs.