Canker Sore or Cancer?

By Dr. Wilson Kwong
I have a sore in my mouth. How can I be sure whether it is a canker sore or oral cancer?

In addition to checking for cavities and gum disease, dentists look for signs of oral cancers when we do an examination during a checkup. We look at the most common areas where oral cancer is found: under the tongue and on the floor of the mouth, on and around the sides of the tongue, in the back of the throat, on the sides of the cheeks, on the roof of the mouth, and around the lips. Sometimes an X-ray will reveal cancer in the bones of the upper or lower jaw or in the spaces in the sinuses. Dentists will also examine the neck for unusual swellings or hardening of the lymph nodes, which may indicate cancer in the throat. One of my patients noticed an unusual change in his voice and later found that he had a tumor on his larynx. Fortunately, it was operable and he continues to sing in his band today.

Oral cancers look like red sores or white patches. They are often painful and irregularly shaped, and bleed easily. Unlike canker sores or cold sores, they do not improve or disappear over time. Teeth around the area may be loose or uncomfortable to chew on. Patients may also notice a lump or thickening in the mouth or throat.

A biopsy is the only certain way to determine if tissue is cancerous. Biopsies can be performed by your dentist or an oral medicine or surgical specialist. The tissue sample is then sent for a histological test at a lab to determine if it is a cancer. Different levels of severity, from benign to malignant, will be assessed and treatment will be recommended. Complete removal of the cancerous tissue is recommended to prevent spread, or metastasis. Treatment may also involve radiation and chemotherapy if it is suspected that the cancer has spread to other parts of the body. Unfortunately, if the cancer is advanced, radical surgery to remove large areas is often required in order to save a patient’s life. This type of surgery can be disfiguring and debilitating to the patient, who will often have difficulty with chewing and swallowing, and may require speech rehabilitation. As with all forms of cancer, early detection is crucial.

There is no absolute prevention of oral cancers. There are ways to reduce your risk, however, such as minimizing drinking, refraining from smoking or chewing tobacco, and eating healthy foods. The combination of alcohol and tobacco is particularly risky, as alcohol thins out or strips away the lining of the oral tissue, which then allows the carcinogens in tobacco to damage the cells. Limiting sun exposure and using a lip balm containing sunscreen will help to prevent cancer on the lips. Infection with the human papilloma virus (HPV) has been linked to several types of cancer, including oral, so practicing safe sex can also help to reduce your risk.

Going to the dentist is an important part of your total wellness and should be done on a regular basis. Ask your dentist to evaluate your overall oral health with a thorough cancer screen.

Keep smiling—sometimes a sore is just a sore!