Forty patients with HNSCC treated with radiotherapy (66-76 Gy) were included. Static FAZA PET/CT imaging 2 h post injection was conducted prior to irradiation. The hypoxic volume (HV) was delineated using a tumor-to-muscle value ?1.4. In 13 patients, a repetitive FAZA PET/CT scan was conducted during the radiotherapy treatment.<h4 class=""h4"">Resultsh4>
A hypoxic volume could be identified in 25 (63 % ) of the 40 tumors. FAZA PET HV varied considerably with a range from 0.0 to 30.9 (median: 0.3) cm3. The Tmax/Mmed ranged from 1.1 to 2.9 (median: 1.5). The distribution of hypoxia among the Human Papillomavirus (HPV) positive (12/16) and negative (13/24) tumors was not significant different. In the FAZA PET/CT scans performed during radiotherapy, hypoxia could be detected in six of the 13 patients. For these six patients the location of HV remained stable in location during radiotherapy treatment, though the size of the HV decreased. In 30 patients a positive correlation was detected between maximum FAZA uptake in the primary tumor and the lymph node. During a median follow up of 19 months a significant difference in disease free survival rate with 93 % for patients with non hypoxic tumors and 60 % for patients with hypoxic tumors could be detected.<h4 class=""h4"">Conclusionh4>
This study emphasizes the role of FAZA PET/CT imaging as a suitable assay with prognostic potential for detection of hypoxia in HNSCC.