FDG-PET and PET-CT Imaging of Head and Neck Cancers.

Head and neck cancers are generally defined as cancers involving all regions of the head and neck, except for the thyroid and central nervous system. Most of these cancers are squamous cell carcinomas. The most common sites are larynx, tongue, floor of the mouth, lip, tonsils, and salivary glands, although these carcinomas can arise at almost any location in the nasopharynx, oropharynx, or hypopharynx. Thyroid cancers and tumors of the central nervous system are usually not included in head and neck cancer classification. The estimated number of new cases in the United States for 2005 is 39,000, with approximately 11,000 deaths (American Cancer Society 2005). The male:female ratio is about 2:1. Primary risk factors for virtually all head and neck cancers are alcohol and tobacco use. Early stage head and neck tumors are treated with either surgery or radiotherapy with excellent prognosis. Locally advanced tumors without distant metastasis are typically treated with surgery and postoperative radiation and hemotherapy or with definitive combination chemoradiation therapy. If chemoradiation is used as the initial treatment, salvage surgery is performed if there is evidence of residual disease. Patients with distant metastatic disease have very poor prognosis and are usually referred for palliative chemotherapy or radiation [ABSTRACT FROM AUTHOR]