Head and neck cancer
![Left inferior internal jugular node metastases with extranodal invasion, two years after brachytherapy of tongue cancer. PET-CT scanning of a male patient in his 30's, 64 minutes after fludeoxyglucose (18F) was administered, shows some fluff around the tumor.](/Images/godic/202501/18/PET-CT_scanning_of_lymph_node_metastases_in_cancer_22237.jpg")
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![Radiation mask used in treatment of throat cancer](/Images/godic/202501/18/Radiation-mask2237.jpg")
![When DNA undergoes oxidative damage, two of the most common damages change guanine to 8-hydroxyguanine or to 2,6-diamino-4-hydroxy-5-formamidopyrimidine.](/Images/godic/202501/18/Guanine_and_2_oxidative_products.svg2237.png")
Head and neck cancer is cancer that starts in the lip, oral cavity (mouth), nasal cavity (inside the nose), paranasal sinuses, pharynx, larynx or parotid glands.
Most head and neck cancers are biologically similar. 90% of head and neck cancers are squamous cell carcinomas, so they are called head and neck squamous cell carcinomas (HNSCC). These cancers commonly originate from the mucosal lining (epithelium) of these regions. Head and neck cancers often spread to the lymph nodes of the neck, and this is often the first (and sometimes only) sign of the disease at the time of diagnosis.