Malignant tumors affecting the oral cavity; most common are lip cancer and tongue cancer. The floor of the mouth, the salivary glands, the inside of the cheeks, the gums, and the palate are less commonly affected. Most are squamous carcinomas.
CAUSES AND INCIDENCE
The main cause of oral cancer is smoking. Tobacco smoke and heat irritate the mucous membrane lining the mouth. The risk to pipe and cigar smokers is as great, or greater, than to cigarette smokers. The other chief causes are chewing tobacco, inhaling snuff, and heavy alcohol consumption. Poor oral hygiene and irritation from ill-fitting dentures or jagged teeth are predisposing factors. Oral cancers represent about 8 percent of all malignancies. Men are twice as commonly affected as women, and most cases occur in men older than 40.
SYMPTOMS AND SIGNS
Cancer of the lip usually starts with a whitish patch on the lower lip called leukoplakia. The lesion is a small ulcer, or a deep, hard-edged fissure, and may be the first sign of a malignant tumor in the mouth. These initial tissue changes may be accompanied by a burning sensation, but are usually painless. As the tumor grows, it develops into an ulcer that may bleed and that erodes surrounding tissue. If the tongue is affected, it becomes stiff, making chewing, swallowing, and speaking difficult. In its advanced stages, the tumor is usually painful.
Any lump, discolored patch, or other tissue change on the lip or in the mouth that does not clear up within a month should be reported to a physician. In some cases, a dentist is tne first person to detect such a change. The diagnosis is based on a biopsy (removal of a small sample of tissue).
TREATMENT AND OUTLOOK
Treatment consists of surgical removal of all cancerous tissue, radiation therapy, or a combination of both. Extensive surgery may result in facial disfigurement and problems with eating and speaking, which may require reconstructive surgery. Radiation therapy sometimes damages the salivary glands (see Mouth, dry). The rate of spread of oral cancer varies according to the site. Tongue cancer is the most dangerous, spreading rapidly to nearby lymph nodes. When oral cancer in any form is detected and treated early, the outlook is good, resulting in a cure in three quarters of cases. More than half the people with oral cancer survive for more than five years after treatment.