Head and neck tumor hypoxia imaging by 18F-fluoroazomycin-arabinoside (18F-FAZA)-PET: A review

Tumor hypoxia is known to be associated with poor clinical outcome; therefore, patients with hypoxic tumors might benefit from more intensive treatment approaches. This is particularly true for patients with head and neck cancer. Pretreatment assessment of hypoxia in tumors would be desirable, not only to predict prognosis but also to select patients for more aggressive treatment. As an alternative to the invasive polarographic needle electrode method, there is the possibility of using PET with radiopharmaceuticals visualizing hypoxia. Most hypoxia imaging studies on head and cancer have been performed using F-18-labeled fluoromisonidazole (F-18-FMISO). A chemically related molecule, F-18-fluoroazomycin-arabinoside (F-18-FAZA), seems to have superior kinetic properties and may therefore be the radiopharmaceutical of choice. This minireview summarizes the published literature on animal and human F-18-FAZA PET studies. Furthermore, future perspectives on how individualized treatment could be applied in patients with hypoxic head and neck tumors are discussed, for instance, the use of hypoxia sensitizers or special intensity-modulated radiation therapy techniques achieving tumor subvolume dose escalation