Introduction

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. In the USA it accounts for approximately 2% of all cancers and 2% of cancer-related deaths. Nevertheless, HNSCC is an important topic in oncologic imaging, because imaging findings can aid significantly in the detection, staging, and treatment evaluation of these tumors. Patients presenting with primary tumors that are confined at the time of initial diagnosis (T1/2N0M0) have an excellent cure rate. Unfortunately, at the time of initial diagnosis many patients already have regional nodal metastases (45%) or even distant metastases (10%). Also noteworthy is the approximately 5% annual rate of second primaries in HNSCC patients, mostly occurring in the upper aerodigestive tract. The most appropriate treatment approach for HNSCC varies with the disease stage and disease site in the head and neck. Concurrent chemoradiotherapy has become a widely used means for the definitive treatment of locoregionally advanced HNSCC.

Probably 98% of PET studies in patients with head and neck cancer are performed using FDG as the radiotracer. The widespread clinical introduction of FDG-PET/CT in the work-up of patients with HNSCC has improved staging accuracy and patient management (1). Today, essentially all patients are examined on combined PET/CT scanners. Studies have shown that combined PET/CT improves the detection of focal FDG uptake in the head and neck and its clear characterization as either benign or malignant. For the overall assessment of disease status, combined PET/CT is more accurate then either modality alone (2–4). This translates into improved patient care (2, 5). The clinical indications of PET/CT in head and neck cancer include: the detection of an unknown primary tumor in patients presenting with neck node metastases; tumor staging (lymph nodes, distant disease); radiotherapy planning; treatment response assessment, usually after concurrent chemoradiotherapy, and sometimes also in patients with advanced disease treated with targeted therapies; and the detection of recurrent disease.