Distant metastases from head and neck squamous cell carcinoma. Part II. Diagnosis.

The detection of distant metastases is critical for prognostication and for the choice of treatment in patients with head and neck squamous cell carcinoma (HNSCC). Pretreatment screening for distant metastases should be conducted particularly for patients with high risk factors, prior to locoregional treatment decisions. Different diagnostic techniques are discussed. Unfortunately, most studies lack sufficient follow-up to reliably assess false-negative results. Moreover, the designs of most studies vary substantially with regard to homogeneity of groups (tumor types and stages), timing (pretreatment, follow-up) and definition of risk factors (patient selection). Therefore, only a few studies are comparable. The combination of F-18 fluoro-d-glucose-positron emission tomography (FDG-PET) and a dedicated CT (at least of the chest) is the most important imaging protocol at the present time. Eventually, whole-body-MRI (WB-MRI) may possibly replace PET-CT for screening patients for distant metastases.