Reduction of [18F]Fluoromisonidazole Uptake After Neoadjuvant Chemotherapy for Head and Neck Squamous Cell Carcinoma

The purpose of this study was to investigate the changes of tumor hypoxia as a result of neoadjuvant chemotherapy (NAC) by measuring the changes of [F-18]fluoromisonidazole ([F-18]FMISO) positron emission tomography (PET) uptake, as well as to look into the ability of [F-18]FMISO PET to predict the NAC result. A total of 13 patients with locally advanced head and neck squamous cell carcinoma underwent [F-18]FMISO PET scans before and after NAC. For analysis of PET index, maximum standardized uptake value, tumor-to-muscle ratio, and hypoxic volume (HV) were measured. All PET indexes of [F-18]FMISO significantly decreased after NAC. Although HV in primary tumor and a few indexes before NAC in responder was lower than that in nonresponder, none of the indexes were statistically significant. Pretreatment [F-18]FMISO could not predict NAC outcome in this study. However, [F-18]FMISO uptake significantly decreased after NAC, and [F-18]FMISO PET seemed to be a useful noninvasive tool for detecting hypoxia reduction after NAC.