There are four major types of throat cancers. The most common type is called oropharyngeal cancer, which develops just behind the mouth, in the area of the throat known as the oropharynx. This includes the back one-third of the tongue, the soft palate, the tonsils and tonsillar pillars and the back wall of the throat, known as the posterior pharyngeal wall.

More than 90 percent of cancers in the oropharynx are squamous cell carcinomas. Invasive oropharyngeal cancer that spreads into the deep tissue layers of the oropharynx is more common in African Americans than in white people. The rate of incidence has been declining for more than two decades, which may be due to a decline in smoking.

The tonsils and base of the tongue contain immune system (lymphoid) tissue that can develop into a cancer. But these cancers are not as common as squamous cell carcinomas.

Patients diagnosed with oropharyngeal cancer often have other associated cancers. Upon initial diagnosis, about 15 percent are found to have another cancer in a nearby area such as the voice box (larynx), the esophagus or the lung, according to the American Cancer Society (ACS). Another 10 percent to 40 percent will develop such cancers at a later time.

Laryngeal cancer (cancer of the larynx, or “voice box”) is the second most common type of throat cancer. The larynx contains the vocal cords and is located in the front of the neck in the area commonly known as the “Adam’s apple,” which is more prominent in men. The larynx is divided into three sections, with the cancer treated differently depending on where it starts:

• Glottis. The area between the vocal cords. Vocal cords open when a person breathes to let air into and out of the lungs. They are largely responsible for voice production, including pitch and sound of a person’s voice. About 60 percent of laryngeal cancers begin in the vocal cords, according to the ACS.
  
  
• Supraglottis. Area above the vocal cords. It includes the epiglottis, which closes off the larynx during swallowing and helps prevent food from entering the windpipe (trachea). About 35 percent of laryngeal cancers begin in the supraglottis, according to the ACS. 
  
  
• Subglottis. Area below the vocal cords. About 5 percent of laryngeal cancers begin in the subglottis, according to the ACS.

As with oropharyngeal cancer, almost all laryngeal cancers develop from squamous cells in the lining layer of the larynx. Cancers such as chondrosarcomas or synovial sarcomas very rarely develop from connective tissues of the larynx.

Hypopharyngeal cancer is the third most common form of throat cancer. Cancer cells grow in the hypopharynx, which is the entrance to the esophagus, or food pipe, that lies beside and behind the larynx. Food travels through the hypopharynx into the esophagus before reaching the stomach. The structure of the hypopharynx ensures that food goes around the larynx and into the esophagus.

Like oropharyngeal and laryngeal cancers, almost all hypopharyngeal cancers develop from squamous cells in the lining layer of the hypopharynx. Cancers such as chondrosarcomas or synovial sarcomas very rarely develop from connective tissues of the hypopharynx.

The rarest form of throat cancer is nasopharyngeal cancer, which develops in the nasopharynx, an area at the back of the nose near the base of the skull and located just above the soft palate. It differs from the other throat cancers in that it tends to spread widely and is not often treated with surgery. This type of cancer also has different risk factors than the other throat cancers. 

Nasopharyngeal carcinoma (NPC) is the most common malignant tumor of the nasopharynx. There are three types of NPC:

• Keratinizing squamous cell carcinoma (type 1)
• Nonkeratinizing carcinoma (type 2)
• Undifferentiated carcinoma (type 3)

Treatment is usually the same for all three types of NPC. When determining the prognosis for these cancers, the extent that the disease has spread is more important than the type of NPC. 

Nasopharyngeal cancer is rare in North America, where it accounts for less than 1 percent of all cancers and about 2 percent of all head and neck cancers, according to the ACS. However, the cancer is much more common in areas of Asia and North Africa. The prevalence of the Epstein-Barr virus (the virus that causes infectious mononucleosis) along with cultural dietary preferences, such as salt-preserved foods, are associated with the incidence of this cancer. It also occurs more often in immigrant groups in the United States, such as recent Chinese immigrants and people from Southeast Asia. NPC most often affects people between ages 30 and 50, but is occasionally seen in children.