PET Imaging of Tumor Hypoxia Using F-18-Fluoroazomycin Arabinoside in Stage III-IV Non-Small Cell Lung Cancer Patients

Tumor hypoxia hampers the efficacy of radiotherapy because of its increased resistance to ionizing radiation. The aim of the present study was to estimate the potential added clinical value of the specific hypoxia tracer F-18-fluoroazomycin arabinoside (F-18-FAZA) over commonly used F-18-FDG in the treatment of advanced-stage non-small cell lung cancer (NSCLC). Methods: Eleven patients with stage Ill or stage IV NSCLC underwent F-18-FDG and F-18-FAZA PET before chemoradiotherapy. The maximum standardized uptake value (SUVmax) was used to depict F-18-FDG uptake, and the tumor-to-background (T/B) ratio and tumor fractional hypoxic volume (FHV) were used to quantify hypoxia. The spatial correlation between F-18-FDG and F-18-FAZA uptake values was investigated using voxel-based analysis. Partial-volume correction was applied. Results: All 11 patients showed clear uptake of F-18-FAZA in the primary tumor. However, different patterns of F-18-FDG and F-18-FAZA uptake distributions were observed and varied widely among different tumors. No significant correlation was observed between F-18-FDG SUVmax and F-18-FAZA T/B ratio (P = 0.055). The median FHV of 1.4 was 48.4% (range, 5.0-91.5). A significant positive correlation was found between the F-18-FAZA T/B ratio and FHV of 1.4 (P