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Risks and causes

The risks and causes of mouth and oropharyngeal cancer include lifestyle factors and other medical conditions. See what you can do to reduce your risk.

We don’t know what causes most mouth or oropharyngeal cancers. But there are some factors that may increase your risk of developing it.

Having any of these risk factors does not mean that you will definitely develop cancer.

Alcohol

Drinking alcohol increases your risk of mouth and oropharyngeal cancer, especially when combined with smoking. Research shows around 30 out of 100 (30%) of mouth and oropharyngeal cancers are caused by drinking alcohol.

UK guidelines suggest a maximum of 14 units of alcohol a week for both men and women. 

Smoking

Smoking tobacco (cigarettes, pipes, cigars) increases your risk of developing mouth and oropharyngeal cancer. Research suggests that more than 60 out of 100 (more than 60%) of mouth and throat cancers in the UK are caused by smoking.

People exposed to second hand smoke (passive smoking) at home or in the workplace have a small increase in their risk of mouth and oropharyngeal cancer. 

Chewing tobacco or betel quid

Chewing tobacco (smokeless tobacco) or betel quid (gutkha) is known to cause mouth and oropharyngeal cancer. It is not a safe alternative to cigarettes. It is very common in parts of Asia, Europe and USA. 

Diet

A poor diet may increase your risk of some types of mouth and oropharyngeal cancer. This might be due to a lack of vitamins and minerals, such as iron or folic acid. Poor diet can lead to a breakdown in oral mucosa, making it more prone to developing cancer. A well balanced diet usually means you are getting enough vitamins and minerals. 

Human papilloma virus (HPV)

Viruses can cause some cancers. You don't catch cancers like an infection. But the virus can cause cell changes making them more likely to become cancerous in the future. 

There are many types of HPV. Mouth and oropharyngeal cancer are especially linked to type 16. 

Human papilloma virus is a sexually transmitted infection. It is very common. For many people, HPV causes no harm and goes away without treatment. Only a very small percentage of people with HPV develop mouth or oropharyngeal cancer. 

The risk of HPV infection in the mouth and throat is linked to certain sexual behaviours, such as oral sex and having a higher number of sexual partners. Smoking also increases the risk of HPV infection in the mouth.

Weak immune system

Your body's immune system fights infection. Some illnesses and medication can weaken your immune system. Research shows an increased risk of mouth cancer if you are:

  • having treatment for HIV or AIDS
  • taking medicines to suppress your immune system after an organ transplant

Sunlight and sunbeds

Skin cancers are relatively common on the head and neck as these areas are often exposed to ultraviolet (UV) light. Melanoma (skin cancer) can develop on the lip.

Both the sun and tanning beds give off UV rays. These rays can cause cancer in unprotected skin.  Some studies have shown an increase in skin cancer in people who regularly use sunbeds.

Previous cancer

People who have had a mouth or orpharyngeal cancer have an increased risk of getting a second one. 

People who have the following cancers are also at increased risk of mouth and orpharyngeal cancer:

  • cancer of the food pipe (oesophagus) 
  • squamous cell skin cancer 
  • cervical cancer 
  • penile cancer 
  • anal cancer 

Family history

Research shows a slight increase in risk of mouth and oropharyngeal cancer if you have a close relative (parent, sibling, or child) who has had mouth cancer. Further research is needed to understand why this is. 

Mouth conditions

Changes can happen in the cells in the lining of the mouth. They can appear as red or white patches in the mouth. The red patches are called erythroplakia. White patches are called leukoplakia.

In some people, these conditions may develop into cancer over some years. Doctors call these conditions precancerous. 

Dentists can spot these patches during your dental check ups so it is important to go for regular dental appointments. 

Genetic conditions

People with certain conditions caused by inherited cell changes (mutations) have an increased risk of mouth and orpharyngeal cancer. These conditions include:

  • fanconi anaemia (a genetic condition affecting the bone marrow)
  • dyskeratosis congenita (a condition causing changes to bone marrow, skin or fingernails) 

Blood pressure drug (hydrochlorothiazide)

Hydrochlorothiazide is a drug to treat high blood pressure (hypertension). A side effect is increased sensitivity to sunlight (photo sensitvity). A small study showed this medicine might lead to an increased risk of developing lip cancer. 

For detailed information on mouth or orpharyngeal cancer risks and causes

Last reviewed: 
13 Nov 2014
  • Head and Neck Cancer: Multidisciplinary Management Guidelines
    British association of head and neck oncologists (2011) 4th edition

  • Tobacco-attributable cancer burden in the UK in 2010 
    DM Parkin 
    British Journal of Cancer 2011, Volume 105 , Supplement 2, Pages S6-S13

  • Cancers attributable to consumption of alcohol in the UK in 2010
    Parkin DM
    British Journal of Cancer, 2011, Volume 105 , Supplemenet 2, Pages S14-S18.

  • List of Classifications by cancer sites with sufficient or limited evidence in humans, Volumes 1 to 105
    International Agency for Research on Cancer,  accessed May 2013.

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. If you need additional references for this information please contact patientinformation@cancer.org.uk with details of the particular risk or cause you are interested in.

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