Clinical Value of FAZA-PET/CT in Head and Neck Cancer Patients

Aim: The presence of hypoxia in cancer tissue is known to increase not only their refractoriness to treatment, but also their malignant potential. The information of cancer hypoxia, therefore, is important for the management of cancer patients such as prediction of treatment response and the selection of appropriate treatment strategy. The aim of the present study was to evaluate the clinical value of PET/CT with FAZA, a PET probe to detect cancer hypoxia, in head and neck cancer patients, especially on the prediction of patients’ prognosis. Materials and Methods: Twenty-nine patients with head and neck cancer (stage I: 1 patient, stage II: 2 patients, stage III: 8 patients, stage IV: 18 patients; squamous cell carcinoma (SCC): 26 patients, non-SCC: 3 patients) received FAZA-PET/CT before treatment. Patients were followed to determine the treatment response and survival. Uptake parameters of FAZA (tumor-muscle ratio at 2 hours post-injection (T/M)) in primary lesion and lymph node metastasis were compared with various clinical parameters. Progression-free survival (PFS) was compared with clinical and FAZA uptake parameters in SCC patients who received chemoradiation therapy (CRT). Study protocol was approved by the institutional review board, and informed consent was obtained from all patients. Results: Among SCC cases, there was a significant correlation between FAZA primary T/M and maximal diameter of primary lesion (P = 0.007, r = 0.517). FAZA primary T/M was significantly higher in stage IV patients than in stage I ~ III patients (P = 0.003), and was significantly higher in T2 ~ 4 patients than in T1 patients (P = 0.009). Although not statistically significant, SCC patients who developed disease progression after CRT tended to show higher FAZA primary T/M than those who did not develop disease progression (1.70 ± 0.30 vs. 1.48 ± 0.36, P = 0.095). Kaplan-Meier analysis with Log-Rank test has shown that, among various clinical and PET parameters, only FAZA primary T/M was a significant predictor of PFS (P = 0.010), in which patients with FAZA primary T/M > 1.565 showed significantly worse PFS rate than those with FAZA primary T/M ≤ 1.565. Conclusion: FAZA primary T/M was a significant predictor of PFS in head and neck SCC patients receiving CRT. Pretreatment FAZA-PET/CT can afford useful information on the management of head and neck cancer patients.Annual congress of the European Association of Nuclear Medicine 2015に参加、発表をす