The value of (18)F-FDG PET/CT for the detection of distant metastases in high-risk patients with head and neck squamous cell carcinoma.

The aims of this study were to assess a cohort of patients with head and neck squamous cell carcinoma (HNSCC) for: (1) the prevalence of synchronous distant metastases (DM) as detected by the initial staging by using (18)F-FDG PET/CT, (2) the prevalence of metachronous DM, and (3) the validity of published risk factors with special emphasis on the maximum standardized uptake value (SUV max) for the prediction of DM. Two hundred and ninety nine patients with advanced HNSCC were included. Following risk factors at the time of diagnosis and during follow-up were analyzed: advanced T/N stage, poor histological differentiation, level IV/Vb lymph nodes, primary site in the larynx/hypopharynx, and SUV max. The prevalence of DM at initial staging and during follow-up was 10% and 11%, respectively. At initial staging, primary site in the larynx/hypopharynx and neck nodes in level IV/Vb, and during follow-up only level IV/Vb nodes achieved statistical significance. The sensitivity for (18)F-FDG PET/CT with regard to the detection of DM was 96.8%, the specificity 95.4%, the positive predictive value (PV) 69.8%, and the negative PV 99.6%. Patients without DM showed a significantly better overall survival (OS) than patients developing DM (p<0.001). There was no significant difference in OS with regard to the time of diagnosis of DM. The prevalence for synchronous and metachronous DM in advanced HNSCC is considerable. (18)F-FDG PET/CT is highly accurate for initial staging and follow-up. DM carries a bad prognosis regardless of the time of diagnosis.