Oral Cancer Screening (PDQ®)
What is screening?
Screening is looking for cancer before a person has any symptoms. This can help find cancer at an early stage. When abnormal tissue or cancer is found early, it may be easier to treat. By the time symptoms appear, cancer may have begun to spread.
Scientists are trying to better understand which people are more likely to get certain types of cancer. They also study the things we do and the things around us to see if they cause cancer. This information helps doctors recommend who should be screened for cancer, which screening tests should be used, and how often the tests should be done.
It is important to remember that your doctor does not necessarily think you have cancer if he or she suggests a screening test. Screening tests are given when you have no cancer symptoms.
If a screening test result is abnormal, you may need to have more tests done to find out if you have cancer. These are called diagnostic tests.
General Information About Oral Cancer
Oral cancer may develop in any of the following areas:
- Oral cavity:
See the following PDQ summaries for more information about oral cancer:
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.
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.
Oral Cancer Screening
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.
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.
Risks of Oral Cancer Screening
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.
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 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.
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.
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.