title: 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.
  
  
  OBJECTIVE
  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.
authors.affiliation: Division of Medical Oncology, Princess Margaret Hospital, Toronto, Ontario, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Amir
authors.forename: M
authors.initials: M
authors.lastname: Trinkaus
authors.forename: C E
authors.initials: CE
authors.lastname: Simmons
authors.forename: G
authors.initials: G
authors.lastname: Dranitsaris
authors.forename: M J
authors.initials: MJ
authors.lastname: Clemons
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020533:Angiogenesis Inhibitors / Q000494:pharmacology; D050071:Bone Density Conservation Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000097:blood / Q000188:drug therapy / Q000556:secondary*; D001862:Bone Resorption / Q000097:blood / Q000209:etiology / Q000517:prevention & control*; D001943:Breast Neoplasms / Q000097:blood* / Q000473:pathology; D004164:Diphosphonates / Q000494:pharmacology / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology / Q000627:therapeutic use; D008875:Middle Aged; D042461:Vascular Endothelial Growth Factor A / Q000097:blood* / Q000187:drug effects; D000077211:Zoledronic Acid
chemical_list: D020533:Angiogenesis Inhibitors; D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D007093:Imidazoles; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D000077211:Zoledronic Acid