Oral cavity cancer starts in the mouth. It might also be called oral cancer. Oropharyngeal cancer starts in the middle part of the throat just behind the oral cavity that can be seen when the mouth is open.

Cancer starts when cells in the body start to grow out of control. To learn more about how cancers start and spread, see What Is Cancer?

The oral cavity (mouth) and oropharynx (throat)

The oral cavity includes the lips, the inside lining of the lips and cheeks (buccal mucosa), the teeth, the gums, the front two-thirds of the tongue, the floor of the mouth below the tongue, the bony roof of the mouth (hard palate) and the area behind the wisdom teeth (called the retromolar trigone).

The oropharynx is the middle part of the throat just behind the oral cavity. It can be seen when your mouth is wide open. It includes the base of the tongue (the back third of the tongue), the soft palate (the back part of the roof of the mouth), the tonsils, and the side and back walls of the throat.

The oral cavity and oropharynx help you breathe, talk, eat, chew, and swallow. Minor salivary glands all over the oral cavity and oropharynx make saliva (spit) that keeps your mouth and throat moist and helps you digest food.

Ask your doctor to explain or show you where your cancer is. Explore the 3D interactive model here to learn more.

Types of oral cavity (mouth) and oropharynx (throat) cancers

The different parts of the oral cavity and oropharynx are made up of many types of cells. Different cancers can start in each type of cell. These differences are important, because they can determine a person’s treatment options and prognosis.

Squamous cell carcinoma of the oral cavity and oropharynx

Almost all of the cancers in the oral cavity and oropharynx are squamous cell carcinomas, also called squamous cell cancers. These cancers start in squamous cells, which are flat, thin cells that form the lining of the mouth and throat.

The earliest form of squamous cell cancer is called carcinoma in situ. This means that the cancer cells are only in the layer of cells called the epithelium (the top layer of cells lining the oral cavity and oropharynx). This is different from invasive squamous cell cancer, where the cancer cells have grown past the epithelium, into the deeper layers of the oral cavity or oropharynx.