Ideally, patients should perform regular self-oral cancer screening using a mirror to closely examine the lips, cheeks, tongue, and gums. They should also make note of any pain, lumps or sores that do not heal within 2 weeks.
The 4 scenarios shown portray length-time bias: “aggressive” OSCCs progress rapidly (hence the steep curve) and do not benefit from screening. “Less aggressive” OSCCs and OPMDs are detected more frequently by screening and do positively influence survival.
As part of an oral cancer screening, your healthcare provider will look at and feel (palpate) your lips, cheeks, tongue and jaw for any lumps or bumps. They may also use a mirror to see inside your mouth and throat. The Foundation recommends you perform regular self-exams of your mouth, and ask your dentist or doctor to show you how to do this.
Most of the time, an early stage oral squamous cell carcinoma (OSCC) will be asymptomatic and can only be spotted during a screening program. This is the case with oral cancers in the front of the mouth, which are usually related to tobacco and heavy alcohol use; and with oropharyngeal cancers arising from the base of the tongue and tonsils that are more frequently due to human papilloma virus (HPV), a common infection that can lead to cervical cancer.
However, not all OSCCs are equal. Some grow more quickly, leading to a steeper curve on the graph below. These “aggressive” OSCCs have a much shorter potential screening window, and are less likely to be detected in an asymptomatic state. Other OSCCs grow more slowly and are more likely to be screened, resulting in a flatter curve. This is called length-time bias.
Fluorescent Light Test
A special type of light called a tissue autofluorescence blue light is used during an oral cancer screening exam to help find abnormal tissues that may not show up well on a visual examination. The light makes healthy tissue appear dark and abnormal tissue appear white. The light is not specific to finding cancer, and the vast majority of tissue changes it finds are not cancerous.
The most common cause of oral cancer is tobacco and heavy alcohol use, but HPV-related oropharyngeal cancer (cancer that starts in the back of the throat) also occurs, particularly in the tonsils and base of the tongue. Many of these cancers develop as visible precancerous tissue changes, and can be seen by a dental professional during an oral cancer screening.
Research has shown that the most effective way to reduce deaths from oral cancer is early detection. However, the majority of cases of oral cancer are diagnosed at an advanced stage, when they are often asymptomatic and difficult to recognize and treat. Therefore, a high screening attendance rate and accurate referral compliance for expert examination are essential elements of an organized screen.
Cytology, also known as cytopathology, involves examining small samples of body tissues and fluids. It is performed by a certain type of physician called a pathologist or cytopathologist who looks at the cells under a microscope to determine a diagnosis. Cytology tests are commonly used to screen for or diagnose cancer and other diseases.
In cytology, cells that have been spontaneously shed by the body or scraped/brushed off of the surface of the skin are collected for testing. These are then spread on a glass slide and stained with special dyes to reveal their characteristics under the microscope. Cells that are abnormal usually have a larger nucleus and scanty or missing cytoplasm (called a high N/C ratio) which can be indicative of malignancy.
A smear can be used as a diagnostic tool for early oral potentially malignant lesions and is a good complement to clinical examination. However, it should not be used as a substitute for biopsy.
A number of studies have evaluated the utility of cytology as part of case finding for oral cancer. In most cases of oral cancer, it is not found until it has reached a more advanced stage when the outlook is poorer. If more early cancers were diagnosed, the outlook for patients would improve. However, it is not easy to get patients motivated to have their mouths examined for a screening test and even when they do they may be unwilling to have the biopsy procedure done.
As part of the oral cancer screening process, your healthcare provider may rinse your mouth with a special liquid and shine a bright light in it. Healthy tissue will look dark under the light, and abnormal tissue will appear white. If they see an unusual sore, they will need to do additional testing. This is called cytology.
They will collect cells from a sample of the suspicious area with a brush, piece of cotton or wooden stick and send them to a lab for examination. A pathologist (a doctor who specializes in the causes and nature of disease) will look at the cells under a microscope and determine whether they are normal, cancerous or precancerous. If the biopsy shows that the tissues are not cancerous, you will not need any further tests or treatment.
But if the biopsy shows that the tissues are cancerous, you will need to undergo surgery and possibly radiation or chemotherapy to cure the disease. And some cancers never cause symptoms or become life-threatening, so they are often found by screening and treated. This is known as overdiagnosis.
Although there is a good chance that regular oral cancer screening will find more cancers at an early stage, it has not yet been proven that it reduces deaths from these diseases. More research is needed to evaluate the balance of benefits and harms.