Hypoxia, Angiogenic Markers, And Response To Neoadjuvant Radiotherapy In Soft-Tissue Sarcomas

10567 Background: Hypoxia is common in soft-tissue sarcomas (STS) and may correlate with radiotherapy (RT) resistance and worse outcomes. We aimed to quantify intratumoral hypoxia with 18-fluoroazamycin arabinoside (FAZA)-PET in resectable STS and correlate this to 18-fluorodeoxyglucose (FDG)-PET, tumour response, angiogenesis biomarkers and patient (pt) outcomes. Methods: This phase II prospective study enrolled pts with resectable STS prior to neoadjuvant RT. Pts underwent FDG-PET and FAZA-PET prior to RT. Circulating and immunohistochemical (IHC) markers of hypoxia and vessel architecture were measured weekly. Response to RT was measured by surgically resected pathologic necrosis (PN), radiological response and relapse-free survival. Results: 23 pts were recruited. 47% (8/17) demonstrated hypoxia on FAZA-PET with a possible association between hypoxia and enhanced metabolic activity on FDG-PET (FDG SUVmax=15.33 with hypoxia; SUVmax=5.86 without hypoxia p=.08). FDG-PET response to RT correlated with PN ...