Cancer of the oral cavity (mouth) is the most common type of head and neck cancer. Oral cancer can begin in the lips, the gums, the area behind the molars or wisdom teeth, the inside of the lips and cheeks, the floor and roof (hard palate) of the mouth, and the tongue. Most oral cancers arise in the tongue, the lip, the floor of the mouth, and the minor salivary glands. The rest are found in the gums and other sites.
The main risk factors for oral cancer are smoking, chewing tobacco or substances such as betel nut and excessive alcohol use. People who both smoke and drink heavily may be as much as 100 times more likely to develop oral cancer than those who neither smoke nor drink. Additional risk factors for oral cancer include infection with the human papillomavirus (HPV) — although this risk is not as high as it is for pharyngeal (throat) cancer — and prolonged exposure to sunlight (lip cancer).
Many oral cancers are found incidentally during a routine dental examination. Most of these cancers can be cured if discovered early. The most common symptoms include a sore or lump on the lip or in the mouth that does not heal; a white and/or red patch on the gums, tongue, or cheeks (these white or red areas may also be a precancerous condition called dysplasia); unusual or persistent bleeding, pain, or numbness in the mouth; and swelling that causes dentures to fit poorly or become uncomfortable.