The exact cause is unknown. Smoking and other tobacco use are associated with most cases of oral cancer. Smoke and heat from cigarettes , cigars , and pipes, irritate the mucous membranes of the mouth. Use of chewing tobacco or snuff causes irritation from direct contact with the mucous membranes. Heavy alcohol use is another high-risk activity associated with oral cancer.
Many oral cancers begin as leukoplakia or mouth ulcers .
Men are affected twice as often as women, particularly men over 40 years old. As the tumor enlarges, it may ulcerate and bleed. Speech difficulties , chewing problems, or swallowing difficulties may develop, particularly if the cancer is on the tongue. A tongue biopsy , gum biopsy and microscopic examination of the lesion confirms the diagnosis of oral cancer. Radiation therapy may be advised.