Definition and Overview
Also referred to as mouth cancer, oral cancer is a broad term for any malignant tumours that develop within the oral cavity such as the gums, tongue, tonsils, and salivary glands, as well as the throat and pharynx (windpipe). Oral or mouth cancers are usually treated as part of the head and neck cancers, which subsequently cover cancer of the thyroid glands, esophagus, ears, and eyes. Brain cancer, meanwhile, is treated as a different category.
Unlike other forms of cancer, oral carcinoma is uncommon, affecting only 1 in 50 in the UK and around 45,000 in the United States. It is treatable through combined therapies if the symptoms are caught early. While the disease commonly develops among senior adults, recent studies suggest it is becoming prevalent among young ones with the increased cases of HPV (human papilloma virus), the same virus group that causes genital warts and/or cervical cancer.
Oral cancers can be:
Squamous cell carcinoma – More than 85% of oral cancer cases is squamous cell carcinoma, wherein the cells that line the inside of the mouth and the lips become abnormal. The location of the actual cancer can help determine the prognosis. For example, if it affects the lower lip, metastasis is rare. On the contrary, lesions on the upper lip can be aggressive. A subtype of this disease is called verrucous carcinoma, which accounts for less than 7% of the number of cases. Not only is this rare, but it is almost always localized (doesn’t metastasize) since it develops slowly.
Carcinoma of the salivary glands – Many salivary glands are found within the mouth and along the throat; a cellular abnormality of any of these glands can lead to cancer such as low-grade polymorphous and adenoid cystic cancer.
Tongue cancer – The cancer can begin either at the base (farther end of the tongue) or in the most visible part of the tongue. Bigger tumours are at risk of spreading to the lymph nodes, especially if they are found at the base of the tongue, which may then require a more complicated surgery including resection.
Lymphoma – This is a cancer that affects the lymph tissues that are part of the immune system. In the oral cavity, these tissues can be found in the tongue and tonsils.
Causes of Condition
Other than the fact that cells in the oral cavity and the throat develop abnormalities, there’s no clear explanation as to why cancer in these regions develops. However, there are certain factors that increase the risk. These include:
Alcohol consumption – The amount of alcohol consumed rather than the kind of beverage determines the likelihood of having oral cancer later on. The risk increases when it is combined with smoking. Alcohol is attributed to carcinoma affecting the esophagus, throat, and voice box. Over time, the components of the alcohol can irritate the cells and cause damage to the tissues while slowing down the DNA repair.
HPV – There are more than 150 strains of HPV, and less than 10 of them can cause cancer. In terms of oral cancer, a very strong causative agent is HPV16, which incidentally also causes around 80% to 90% of cervical cancer. This virus is transmitted through sexual contact (oral, in terms of mouth cancer) in which the virus touches and penetrates the mucosa. HPV is predicted to become one of the leading causes of non-smoking related oral cancers among men and women below 50 years old.
Tobacco use – About 8 in every 10 cases of oral cancer can be blamed on smoking. Tobacco not only damages the tissue up to the DNA level but also alters it. Although the risk is lesser, people who are exposed to tobacco through secondhand smoking may develop mouth or oral cancer.
Gender – Males are more vulnerable to oral cancer since they are the ones more likely to smoke and drink at the same time. However, over the years, the ratio between men and women with cancer has been decreasing.
Age – Most oral cancers have been diagnosed in men and women who are around 40 to 50 years old, but with the increased cases of HPV, it is also now seen among young adults.
- Lesions on the lip, tongue, inner cheeks, and gums that recur or don’t go away
- Difficulty in swallowing or speaking
- Change of voice quality such as hoarseness
- Pain in the ears
- Presence of a lump
- Throat discomfort
- Unintended weight loss
- Mouth numbness
- Loosened teeth
Two distinct signs of oral cancer are leukoplakia and erythroplakia. When a person has leukoplakia, there will be persistent white patches on the tongue. Erythroplakia, meanwhile, causes raised red areas that can bleed. Although considered benign, they already signify cellular abnormalities and can, therefore, develop into cancer.
Who to See and Treatments Available
For oral problems, the first person to see is the dentist who can perform a series of tests including an oral cancer exam, which is a quick and painless procedure. The dentist inspects different parts of the oral cavity and the neck for any possible sign of cancer or changes in texture and color. Other tests can be toluidine and fluorescence staining, which use staining or special light to identify the presence of cancer. These are often performed when lesions are found in the mouth and lips. Take note, however, there’s no universal standard test in determining and diagnosing oral cancer.
To confirm or rule out cancer, a biopsy or exfoliative cytology is performed to collect cell samples that are then studied in the lab.
Once cancer is confirmed, the patient is referred to an oral oncologist, who then creates a treatment protocol that includes any or all of the following:
Surgery – The first form of treatment is surgery to physically remove as much of the tumour as possible. If the cancer has already spread to the lymph nodes, they should be removed as well. Depending on how much cancer has remained, the patient then undergoes chemotherapy and/or radiation therapy.
Chemotherapy – In chemotherapy, certain drugs or a combination of them is delivered in many ways to kill cells including cancer cells. Recently, more targeted therapies are proven to be more effective and efficient since they significantly reduce side effects including a compromised immune system.
Radiation therapy – This can be internal or external depending on the location of the cancer. In internal radiation, radioactive seeds or dyes are delivered to the affected area.
Risks can also be reduced by:
- Quitting smoking and alcohol
- Increasing intake of supplements such as folate
- Going to routine dental exams (at least once a year)
Boosting proper nutrition
National Cancer Institute: PDQ Lip and Oral Cavity Cancer Treatment. Bethesda, Md: National Cancer Institute. Date last modified: July 16, 2012. Available at: http://cancer.gov/cancertopics/pdq/treatment/lip-and-oral-cavity/HealthProfessional.
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines): Head and neck cancers. Version 2.2013. Available at: http://www.nccn.org/professionals/physician_gls/pdf/head-and-neck.pdf.
Wein RO, Malone JP, Weber RS. Malignant neoplasms of the oral cavity. In: Flint PW, Haughey BH, Lund VJ, et al., eds. Cummings Otolaryngology: Head and Neck Surgery. 5th ed. Philadelphia, Pa: Elsevier Mosby; 2010:chap 96.