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Oral cancer

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Risk factors for oral cavity cancer

A risk factor is something that increases the risk of developing cancer. It could be a behaviour, substance or condition. Most cancers are the result of many risk factors. Tobacco and alcohol are the most important risk factors for oral cavity cancer.

Oral cavity cancer is rare in children and young adults. The risk of developing oral cavity cancer increases with age. It is greatest after 45 years of age. More men than women develop oral cavity cancer, and it occurs more often in men of African descent. Some studies show that low socio-economic status, lack of education and low income are linked with a higher rate of oral cavity cancer.

Risk factors are generally listed in order from most to least important. But in most cases, it is impossible to rank them with absolute certainty.

Known risk factors

There is convincing evidence that the following factors increase your risk for oral cavity cancer.

Tobacco

Most oral cavity cancers are linked to tobacco use. All forms of tobacco increase the risk for this cancer, including cigarettes, cigars, pipes, bidis and smokeless tobacco (including chewing tobacco and snuff). The risk of oral cavity cancer increases with how long you use tobacco and how much tobacco you use.

Smoking cigarettes, cigars or pipes increases the risk of cancer anywhere in the oral cavity. These products are often linked with cancer of the lip if they sit on the lips. The risk of oral cavity cancer greatly increases when smoking is combined with using smokeless tobacco, drinking alcohol or both.

Using smokeless tobacco, including chewing tobacco and snuff, increases your risk of oral cavity cancer. Using smokeless tobacco is linked with cancer of the gums and inner lining of the cheeks and lips because the tobacco regularly touches these areas.

Continuing to smoke after treatment for oral cavity cancer increases the risk of developing a second cancer in the oral cavity.

Alcohol

Alcohol is one of the main risk factors for oral cavity cancer. The more you drink, the greater your risk. Using alcohol and tobacco together increases the risk of developing oral cavity cancer more than using either one alone.

Betel quid and areca nut

Betel quid, or paan, is areca nut (the seed from the fruit of the oriental palm) and lime wrapped in a betel leaf. Some people chew areca nut by itself.

Chewing betel quid or areca nut is common in South Asia and among some South Asian immigrants in Canada. Betel quid and tobacco are often chewed together, or betel quid may contain tobacco.

Betel quid and areca nut contain cancer-causing substances. People who chew betel quid or areca nut have a higher risk of developing oral cavity cancer, especiallyin the inner lining of the cheeks and lips.

Human papillomavirus (HPV)

HPV is a group of more than 100 different types of related viruses. Many types of HPV are spread through sexual contact, including oral sex. They can infect the sexual organs (the penis in men or the vulva, vagina and cervix in women), the rectum and the anus. They can also infect the oral cavity and throat.

The different types of HPV are usually given a number to identify them. Infection with HPV-16 increases the risk of oral cavity cancer. Infection with HPV-18 may also increase the risk. HPV is likely the cause of oral cavity cancer that is not linked with tobacco or alcohol use.

Find out more about human papillomavirus (HPV).

Precancerous conditions

People with precancerous conditions of the oral cavity, such as leukoplakia, erythroplakia and oral submucous fibrosis, have a higher risk of developing oral cavity cancer. These precancerous conditions are often found in people who smoke and drink alcohol heavily or who chew betel quid. Erythroplakia, which is abnormal red spots or areas lining the mouth, has the greatest risk of developing into oral cavity cancer.

Find out more about precancerous conditions of the oral cavity.

Previous cancer

People who have had cancer of the oral cavity have a higher risk of developing another oral cavity cancer, especially if they continue to use tobacco or alcohol. Having cancer of the esophagus, larynx, lung or cervix also increases your risk of oral cavity cancer.

Family history of squamous cell carcinoma (SCC)

SCC is the most common type of oral cavity cancer. The risk of developing SCC in the head and neck region (including the oral cavity) is increased if a first-degree family member (parent, sibling or child) has been diagnosed with SCC of the head and neck.

Sun exposure

Sun exposure increases the risk of developing lip cancer. This is especially true for people who work in the sun for long periods of time, such as farmers. Fair-skinned people also have a greater risk of developing lip cancer. Most lip cancers occur on the bottom lip, likely because it’s more exposed to the sun.

Diet low in vegetables and fruit

Many studies have shown that not eating enough vegetables and fruit increases the risk of developing oral cavity cancer. Substances like carotenoids, which are common in vegetables and fruit, are linked with a lower risk of oral cavity cancer.

Weakened immune system

Your immune system can be weaker after you have an organ transplant or you are treated for an immune system disease. People with a weakened immune system have a higher risk of developing oral cavity cancer, especially lip cancer. The higher risk may be due to HPV infection or taking drugs that suppress your immune system.

Graft-versus-host disease (GVHD)

People who have a stem cell transplant may develop GVHD. GVHD is when the healthy transplanted stem cells see the body as foreign and start to destroy the body’s cells, including cells in the mouth. Damage to cells in the mouth from GVHD increases the risk of developing oral cavity cancer.

Find out more about graft-versus-host-disease (GVHD).

Lichen planus

Lichen planus is a chronic condition that forms a rash or sores on the skin and inside the mouth, usually on the tongue, gums and lining of the cheeks. Sometimes the sores can develop into ulcers. Having lichen planus with ulcers in the mouth for a long time increases the risk of developing oral cavity cancer.

Possible risk factors

The following factors have been linked with oral cavity cancer, but there is not enough evidence to show they are known risk factors. Further study is needed to clarify the role of these factors for oral cavity cancer.

Poor oral health and dental care

Some studies link poor oral health and dental care to a higher risk for oral cavity cancer. Chronic infections from bacteria and viruses like HPV in the oral cavity may cause cancer to develop.

Poor-fitting dentures

Some studies have shown that having poor-fitting dentures increases the risk of developing oral cavity cancer. Dentures that irritate the tissues in the mouth and cause sores to develop have been linked to the development of cancer.

Second-hand smoke

Second-hand smoke, or environmental tobacco smoke, is a known cancer-causing substance. There is some evidence that exposure to second-hand tobacco smoke increases the risk of oral cavity cancer in non-smokers.

Unknown risk factors

It isn’t known whether or not the following factors are linked with oral cavity cancer. It may be that researchers can’t show a definite link or that studies have had different results. Further study is needed to see if the following are risk factors for oral cavity cancer:

  • alcohol-based mouthwash
  • marijuana
  • Fanconi anemia (a rare genetic condition that affects the bone marrow so it can’t make enough red blood cells, white blood cells or platelets)
  • drinking hot mate (a drink pouring boiling water over the leaves of the yerba mate, often drunk through a metal straw)

Questions to ask your healthcare team

To make the decisions that are right for you, ask your healthcare team questions about risks.

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