Lip and oral cavity cancer is a disease in which malignant (cancer) cells form in the lips or mouth.

The oral cavity includes the following:

• The front two thirds of the tongue.
• The gingiva (gums).
• The buccal mucosa (the lining of the inside of the cheeks).
• The floor (bottom) of the mouth under the tongue.
• The hard palate (the roof of the mouth).
• The retromolar trigone (the small area behind the wisdom teeth).

Most lip and oral cavity cancers start in squamous cells, the thin, flat cells that line the lips and oral cavity. These are called squamous cell carcinomas. Cancer cells may spread into deeper tissue as the cancer grows. Squamous cell carcinoma usually develops in areas of leukoplakia (white patches of cells that do not rub off).

Tobacco and alcohol use can affect the risk of developing lip and oral cavity cancer.

Risk factors for lip and oral cavity cancer include the following:

• Using tobacco products.
• Heavy alcohol use.
• Being exposed to sunlight.
• Being male.
• Being infected with human papillomavirus (HPV).

Possible signs of lip and oral cavity cancer include a sore or lump on the lips or in the mouth.

These and other symptoms may be caused by lip and oral cavity cancer. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

• A sore on the lip or in the mouth that does not heal.
• A lump or thickening on the lips or gums or in the mouth.
• A white or red patch on the gums, tongue, tonsils, or lining of the mouth.
• Bleeding, pain, or numbness in the lip or mouth.
• Change in voice.
• Loose teeth or dentures that no longer fit well.
• Trouble chewing or swallowing or moving the tongue or jaw.
• Swelling of jaw.
• Sore throat or feeling that something is caught in the throat.

Lip and oral cavity cancer may not have any symptoms and is sometimes found during a regular dental exam.

Tests that examine the mouth and throat are used to detect (find), diagnose, and stage lip and oral cavity cancer.

The following tests and procedures may be used:

• Physical exam of the lips and oral cavity: An exam to check the lips and oral cavity for abnormal areas. The doctor or dentist will feel the entire inside of the mouth with a gloved finger and examine the oral cavity with a small long-handled mirror and lights. This will include checking the insides of the cheeks and lips; the gums; the roof and floor of the mouth; and the top, bottom, and sides of the tongue. The neck will be felt for swollen lymph nodes. A history of the patient’s health habits and past illnesses and medical and dental treatments will also be taken.
• Endoscopy: A procedure to look at organs and tissues inside the body to check for abnormal areas. An endoscope (a thin, lighted tube) is inserted through an incision (cut) in the skin or opening in the body, such as the mouth. Tissue samples and lymph nodes may be taken for biopsy.
• X-rays of the head, neck, and chest: An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
• Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist. If leukoplakia is found, cells taken from the patches are also checked under the microscope for signs of cancer.
• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• Exfoliative cytology: A procedure to collect cells from the lip or oral cavity. A piece of cotton, a brush, or a small wooden stick is used to gently scrape cells from the lips, tongue, mouth, or throat. The cells are viewed under a microscope to find out if they are abnormal.
• Barium swallow: A series of x-rays of the esophagus and stomach. The patient drinks a liquid that contains barium (a silver-white metallic compound). The liquid coats the esophagus and x-rays are taken. This procedure is also called an upper GI series.
• PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radionuclide glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.