Cancer is defined as the uncontrollable growth of cells that invade and cause damage to surrounding tissue. Oral cancer appears as a growth or sore in the mouth that does not go away. Oral cancer, which includes cancers of the lips, tongue, cheeks, floor of the mouth, hard and soft palate, sinuses, and pharynx (throat), can be life-threatening if not diagnosed and treated early.

Oral cavity cancer, or just oral cancer, is cancer that starts in the mouth (also called the oral cavity). Oropharyngeal cancer starts in the oropharynx. This is the part of the throat just behind the mouth. Most cancers that form here are a type of cancer called squamous cell carcinoma.