Key Points for This Section

Oral cancer is a disease in which malignant (cancer) cells form in the lips, oral cavity, or oropharynx. The number of new cases of oral cancer and the number of deaths from oral cancer have been decreasing slowly. Tobacco and alcohol use can affect the risk of developing oral cancer.

Oral cancer is a disease in which malignant (cancer) cells form in the lips, oral cavity, or oropharynx.

Oral cancer may develop in any of the following areas:

• Lips.
• Oral cavity:
  • 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 front of the roof of the mouth).
  • The retromolar trigone (the small area behind the wisdom teeth).
• Oropharynx:
  • The middle part of the pharynx (throat) behind the mouth.
  • The back one third of the tongue.
  • The soft palate (the back of the roof of the mouth).
  • The side and back walls of the throat.
  • The tonsils.

Most oral cancers start in squamous cells, the thin, flat cells that line the lips, oral cavity, and oropharynx. Cancer that forms in squamous cells is called squamous cell carcinoma.

See the following PDQ summaries for more information about oral cancer:

• Oral Cancer Prevention ¹
• Lip and Oral Cavity Cancer Treatment ²

The number of new cases of oral cancer and the number of deaths from oral cancer have been decreasing slowly.

The number of new cases and deaths from oral cancer has slowly decreased over the past 30 years. However, the number of new cases of oral cancer caused by certain types of human papillomavirus (HPV) infection has increased. One kind of HPV, called HPV 16, is often passed from one person to another during sexual activity.

Although oral cancer occurs in all adults, it occurs most commonly in older adults. Also, oral cancer occurs more often in blacks than in whites and in men than in women.

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

Anything that increases the chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Risk factors for oral cancer include the following:

• Using tobacco products (includes cigarettes, cigars, pipes, and smokeless and chewing tobacco).
• Heavy alcohol use.
• Chewing betel nuts.
• Being infected with a certain type of human papillomavirus (HPV).
• Being exposed to sunlight (lip cancer only).
• Being male.

Key Points for This Section

Tests are used to screen for different types of cancer. There is no standard or routine screening test for oral cancer.

Tests are used to screen for different types of cancer.

Some screening tests are used because they have been shown to be helpful both in finding cancers early and in decreasing the chance of dying from these cancers. Other tests are used because they have been shown to find cancer in some people; however, it has not been proven in clinical trials that use of these tests will decrease the risk of dying from cancer.

Scientists study screening tests to find those with the fewest risks and most benefits. Cancer screening trials also are meant to show whether early detection (finding cancer before it causes symptoms) decreases a person's chance of dying from the disease. For some types of cancer, the chance of recovery is better if the disease is found and treated at an early stage.

Clinical trials that study cancer screening methods are taking place in many parts of the country. Information about ongoing clinical trials is available from the NCI Web site ³.

There is no standard or routine screening test for oral cancer.

Screening for oral cancer may be done during a routine check-up by a dentist or doctor. The exam will include looking for lesions, including areas of leukoplakia (an abnormal white patch of cells) and erythroplakia (an abnormal red patch of cells). Leukoplakia and erythroplakia lesions on the mucous membranes may become cancerous.

If lesions are seen in the mouth, the following procedures may be used to find abnormal tissue that might develop into oral cancer:

• Toluidine blue stain: A procedure in which lesions in the mouth are coated with a blue dye. Areas that stain darker are more likely to be cancer or become cancer.
• Fluorescence staining: A procedure in which lesions in the mouth are viewed using a special light. After the patient uses a fluorescent mouth rinse, normal tissue looks different from abnormal tissue when seen under the light.
• 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.
• Brush biopsy: The removal of cells using a brush that is designed to collect cells from all layers of a lesion. The cells are viewed under a microscope to find out if they are abnormal.

More than half of oral cancers have already spread to lymph nodes or other areas by the time they are found. No studies have been done to find out if screening would decrease the risk of dying from this disease.

Key Points for This Section

Screening tests have risks. The risks of oral cancer screening include the following: Finding oral cancer may not improve health or help a person live longer. False-negative test results can occur. False-positive test results can occur. Misdiagnosis can occur.

Screening tests have risks.

Decisions about screening tests can be difficult. Not all screening tests are helpful and most have risks. Before having any screening test, you may want to discuss the test with your doctor. It is important to know the risks of the test and whether it has been proven to reduce the risk of dying from cancer.

The risks of oral cancer screening include the following:

Finding oral cancer may not improve health or help a person live longer.

Some cancers never cause symptoms or become life-threatening, but if found by a screening test, the cancer may be treated. Finding these cancers is called overdiagnosis. It is not known if treatment of these cancers would help you live longer than if no treatment were given, and treatments for cancer, such as surgery and radiation therapy, may have serious side effects.

Screening may also find oral cancers that have already spread and cannot be cured. When these cancers are found, treatment may cause serious side effects and not help a person live longer.

False-negative test results can occur.

Screening test results may appear to be normal even though oral cancer is present. A person who receives a false-negative test result (one that shows there is no cancer when there really is) may delay seeking medical care even if there are symptoms.

False-positive test results can occur.

Screening test results may appear to be abnormal even though no cancer is present. A false-positive test result (one that shows there is cancer when there really isn't) can cause anxiety and is usually followed by more tests and procedures (such as biopsy). which also have risks.

Misdiagnosis can occur.

A biopsy is needed to diagnose oral cancer. Cells or tissues are removed from the lips, oral cavity, or oropharynx and viewed under a microscope by a pathologist to check for signs of cancer. When the cells are cancer and the pathologist reports them as not being cancer, the cancer is misdiagnosed. Cancer is also misdiagnosed when the cells are not cancer and the pathologist reports there is cancer. When cancer is misdiagnosed, treatment that is needed may not be given or treatment may be given that is not needed.