title: Evaluation of tumor angiogenesis measured with microvessel density (MVD) as a prognostic indicator in nasopharyngeal carcinoma: results of RTOG 9505.
abstract: OBJECTIVE
  The objective of this study was to evaluate tumor angiogenesis as measured by microvessel density (MVD) as an independent prognostic factor in patients with nasopharyngeal carcinoma (NPC) treated with radiotherapy alone.
  
  
  METHODS
  Eligible patients included those with NPC treated with radiotherapy. Paraffin blocks of the primary tumor had a hematoxylin and eosin-stained section prepared at the block face. One representative section for tumor was stained for factor VIII-related antigen using a standard immunoperoxidase staining technique. MVD was determined by light microscopy in areas of invasive tumor containing the highest numbers of capillaries and microvessels per area. Individual microvessel counts were made on a 200x field within the area of most intense tumor neovascularization. Results were expressed as the highest number of microvessels identified within any single 200x field. Using a breakpoint of MVD <60 vs. > or =60, the distributions between the two MVD groups were compared by the method of Gray. Overall survival rates were estimated by the Kaplan-Meier method and compared by the log-rank test. A multivariate Cox proportional hazard model was employed to examine the relationship between MVD and disease outcomes while adjusting for other concomitant variables.
  
  
  RESULTS
  One hundred sixty-six were eligible, of whom 123 had values determined for MVD. The MVD values ranged from 9 to 243 with a median of 70. In the multivariate analysis of overall survival, distant metastases, and local-regional failure, MVD did not significantly improve the model containing T stage, N stage, age, radiation dose, and World Health Organization class.
  
  
  CONCLUSIONS
  We found no significant differences in overall survival, time to distant metastasis, or time to local-regional failure using a breakpoint of MVD <60 vs. MVD > or =60. The study was perhaps limited by the small size of the NPC samples.
authors.affiliation: Division of Radiation Oncology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA. foote.robert@mayo.edu
authors.forename: Robert L
authors.initials: RL
authors.lastname: Foote
authors.forename: Noel
authors.initials: N
authors.lastname: Weidner
authors.forename: Jonathan
authors.initials: J
authors.lastname: Harris
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hammond
authors.forename: Jean E
authors.initials: JE
authors.lastname: Lewis
authors.forename: Te
authors.initials: T
authors.lastname: Vuong
authors.forename: K Kian
authors.initials: KK
authors.lastname: Ang
authors.forename: Karen K
authors.initials: KK
authors.lastname: Fu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000098:blood supply* / Q000401:mortality / Q000532:radiotherapy*; D009389:Neovascularization, Pathologic / Q000473:pathology*; D011379:Prognosis; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use; D015996:Survival Rate
chemical_list: D011838:Radiation-Sensitizing Agents