Throat cancers are malignant tumors that develop between the rear of the mouth and the esophagus. There are several types, including:

• Oropharyngeal cancer. Cancer of the oropharynx, which is the area just behind the mouth. This is the most common form of throat cancer. The American Cancer Society (ACS) estimates that about 34,000 news cases of oral cavity and oropharyngeal cancer will be diagnosed in the United States in 2007. The ACS predicts that nearly 7,600 individuals will die from this disease the same year.
  
  
• Laryngeal cancer. Cancer of the larynx, or “voice box.” It is the second most common form of throat cancer. There will be more than 11,000 new cases of laryngeal cancer in 2007 and the disease will cause about 3,600 deaths, according to the ACS. These rates are dropping by 2 to 3 percent a year, primarily due to fewer people smoking.
  
  
• Hypopharyngeal cancer. Cancer of the hypopharynx, the entrance to the esophagus, or food pipe. It is the third most common form of throat cancer with an estimated 2,500 new cases in 2007.
  
  
• Nasopharyngeal cancer. Cancer of the nasopharynx, an area at the back of the nose located just above the soft palate. The soft palate, also known as the velum, is a muscular piece of tissue that makes up the rear portion of the roof of the mouth. It separates the mouth from the pharynx and can open and close for swallowing and speaking. This type of cancer is very rare in the United States. In North America, it occurs in only 7 out of every one million patients accounting for about 2,000 cases per year in the United States.

Throat cancers begin when cells in the throat tissue grow and divide abnormally. Groups of abnormal cells in the throat are often classified as one of two types:

• Leukoplakia. A white area of abnormal tissue that is usually noncancerous (benign). However, 25 percent of these abnormalities are cancerous (malignant) or precancerous (dysplasia), according to the American Cancer Society (ACS).
  
  
• Erythroplakia. A slightly raised, red area that bleeds easily when scraped. These abnormalities are usually more serious than leukoplakia, with 70 percent diagnosed as either precancerous or cancerous.

A biopsy of the suspected tissue is needed for laboratory analysis by a pathologist. Biopsies can reveal the exact nature of these abnormalities. Precancerous cells often do not progress to actual cancer and can disappear without any treatment. This is especially true when factors that trigger precancerous conditions – such as tobacco use and heavy drinking – are stopped.

However, some precancerous cells do become cancerous, developing into carcinoma in situ (CIS), the earliest form of cancer. This occurs when cancer cells develop in the lining layer without invading deeper areas of the tissue or spreading to other parts of the body. Most early cancers can be cured, often by stripping or destroying the lining layer with laser surgery. Left untreated, most cancers will spread.

The majority of throat cancers are squamous cell cancers.. Squamous cells are flat, scale-like cells lining the throat.  As cancers spread from the throat, they often destroy nearby tissues and spread to other parts of the body (metastases).

Some areas of the throat have minor salivary glands that can develop cancers as well, including adenocarcinomas, adenoid cystic carcinomas and mucoepidermoid carcinomas. The tonsils and base of the tongue also contain lymphoid tissue that can develop into lymphomas.