Role of positron emission tomography--computed tomography in head and neck cancer.

Head and neck squamous cell carcinoma (HNC) is the sixth most common cancer worldwide. In the United States, it accounts for approximately 2% of all cancers and 2% of cancer deaths. The introduction of integrated positron emission tomography and computed tomography (PET/CT) has revolutionized imaging by permitting improved and more accurate anatomic localization of functional abnormalities in the complex territory of the head and neck region, and PET/CT has become a standard clinical imaging modality in patients with HNC. The main indications for PET/CT in HNC are in pretherapy staging, detection of unknown primaries, and monitoring of therapy response or disease surveillance. Although PET/CT is a promising tool in diagnosis and surveillance of HNC, there is lack of consensus as to its use, accuracy, and implications for patient management. The existing literature on the role of PET/CT in the management of HNC is reviewed, and a summary of the current debate is provided. Second primary cancers are the main cause of death among HNC patients with early disease, and the presence of distant metastases greatly impairs the survival of patients with advanced HNC. Therefore, early detection of second primary and metastatic tumors is imperative for optimizing survival outcome. However, given the lack of randomized, prospective trials addressing the role of PET/CT after chemoradiotherapy, the ideal function of PET/CT in disease surveillance has yet to be defined.