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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.〔(NCI fact sheet on head and neck cancer )〕 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. Head and neck cancer is strongly associated with certain environmental and lifestyle risk factors, including tobacco smoking, alcohol consumption, UV light, particular chemicals used in certain workplaces, and certain strains of viruses, such as human papillomavirus.〔 These cancers are frequently aggressive in their biologic behavior; patients with these types of cancer are at a higher risk of developing another cancer in the head and neck area.〔Ridge JA, Glisson BS, Lango MN, et al. ("Head and Neck Tumors" ) in Pazdur R, Wagman LD, Camphausen KA, Hoskins WJ (Eds) (Cancer Management: A Multidisciplinary Approach ). 11 ed. 2008.〕 Head and neck cancer is highly curable if detected early, usually through surgery, but radiation therapy may also play an important role, while chemotherapy is often ineffective.〔(【引用サイトリンク】title=Estimated New Cancer Cases and Deaths by Sex, US, 2009 )〕 HNSCC is the sixth leading cancer by incidence worldwide and eighth by death. There are 0.5 million new cases a year worldwide. Two-thirds occur in industrialized nations. HNSCC usually develops in males in the 6th and 7th decade. The five-year survival rate of patients with HNSCC is about 40-50%. ==Signs and symptoms== Throat cancer usually begins with symptoms that seem harmless enough, like an enlarged lymph node on the outside of the neck, a sore throat or a hoarse sounding voice. However, in the case of throat cancer, these conditions may persist and become chronic. There may be a lump or a sore in the throat or neck that does not heal or go away. There may be difficult or painful swallowing. Speaking may become difficult. There may be a persistent earache. Other possible but less common symptoms include some numbness or paralysis of the face muscles. Presenting symptoms include *Mass in the neck *Neck pain *Bleeding from the mouth *Sinus congestion, especially with nasopharyngeal carcinoma *Bad breath *Sore tongue *Painless ulcer or sores in the mouth that do not heal *White, red or dark patches in the mouth that will not go away *Earache *Unusual bleeding or numbness in the mouth *Lump in the lip, mouth or gums *Enlarged lymph glands in the neck *Slurring of speech (if the cancer is affecting the tongue) *Hoarse voice which persists for more than six weeks *Sore throat which persists for more than six weeks *Difficulty swallowing food *Change in diet or weight loss 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Head and neck cancer」の詳細全文を読む スポンサード リンク
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