Presenter: Aebersold, DM
Affiliation: Department of radiation oncology, Inselspital Berne, Switzerland
- Angiogenesis is thought to play a role in radiosensitivity.
- The differences in radiosensitivity are thought to be related to the influence of oxygenation, vasculotoxicity of radiation, and angiogenic factors that inhibit radiation effectiveness.
- The purpose of the study was to determine the predictive value of intratumoral microvessel density (IMD) and expression of vascular endothelial growth factor (VEGF) for the radiocurability of patients with squamous cell carcinoma of the oropharynx.
- 100 patients with advanced stage biopsy proven squamous cell carcinoma of the oropharynx were radiacally irradiated to a median dose of 74 Gy.
- 151 paraffin embedded biopsies were processed for immunohistochemistry and the IMD was determined after staining with anti-CD31.
- VEGF expression in tunor cells was assessed after immunostaining.
- The level of VEGF expression did not correlate with local failure.
- Increasing IMD correlated with local failure as shown with Cox multivariate analysis.
- IMD was the only correlative variable on univariate analysis with an odds ratio decrease of .47 to .1 for the primary tumor
- The relative risk for local relapse increased from 1.56-8.91 in the group with the highest vessle count (>130)
- Local failure free survival also correlated with IMD and was significant for tumors with a IMD of <80 when compared to a IMD >130.
- IMD may strongly predict for local treatment failure and radiocurability of patients with SCC of the oropharynx.
- Over-expression of VEGF did not correlate with outcome in this cohort
- Increasing vessel density is counterintuitive when predicting tumor hypoxia, however one likely explanation could be that the more vascular the tumor, the more hypoxic the tissues. - The IMD could be a response to tumor hypoxia.
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