A risk factor is anything that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer.

But just because you have a risk factor or more than one risk factor for a disease does not mean you will get it. Some people who have oral cavity or oropharyngeal cancer do not have any known risk factors, and others who have several risk factors never develop the disease. Even if someone does have one or more risk factors, it is impossible to know for sure how much they contributed to causing the cancer.

Tobacco and alcohol

Some researchers estimate that about 8 out of 10 oral cancers could be prevented by avoiding both tobacco and alcohol use.

Tobacco use

About 8 out of 10 people with oral cavity and oropharyngeal cancers use tobacco, and the risk of developing these cancers is related to how much and how long they smoked or chewed.

Smokers are many times more likely than non-smokers to develop these cancers. Tobacco smoke from cigarettes, cigars, or pipes can cause cancers anywhere in the mouth or throat, as well as causing cancers of the larynx (voice box), lungs, esophagus, kidneys, bladder, and several other organs. Pipe smoking has a particularly significant risk for cancers in the area of the lips that touch the pipe stem. What's more, about 1 out of 3 people who continue to smoke after their cancer seems to be cured will develop a second cancer of the oral cavity, oropharynx, or larynx (voice box), compared with less than 1 in 10 of those who stop smoking.

Oral tobacco products (snuff or chewing tobacco) are associated with cancers of the cheek, gums, and inner surface of the lips. Using oral tobacco products for a long time poses an especially high risk. These products also cause gum disease, destruction of the bone sockets around teeth, and tooth loss.

Drinking alcohol

Drinking alcohol increases the risk of developing oral cavity and oropharyngeal cancers. The risk goes up even more for people who use both tobacco and alcohol. About 7 out of 10 patients with oral cancer are heavy drinkers.

Heavy drinking and smoking

According to some studies, the risk of these cancers in heavy drinkers and smokers may be as much as 100 times more than the risk of these cancers in people who don't smoke or drink.

Gender

Oral and oropharyngeal cancers are about twice as common in men as in women. This may be because men are more likely to use tobacco and alcohol. This difference is decreasing as more women are now using tobacco and drinking.

Ultraviolet light

Sunlight is the main source of ultraviolet (UV) light for most people. Cancers of the lip are more common in people who have outdoor jobs that involve prolonged exposure to sunlight.

Poor nutrition

Several studies have found that a diet low in fruits and vegetables is linked with an increased risk of cancers of the oral cavity and oropharynx.

Human papilloma virus infection

Human papilloma viruses (HPVs) are a group of more than 100 related viruses. Most HPV types cause warts on various parts of the body, but a few HPV types seem to be involved in some cancers. For example, nearly all cancers of the cervix are related to infection with certain HPV types. These same HPV types (especially HPV 16) are found in some oral and oropharyngeal cancers. The current estimate is that HPV may be a factor in about one-fourth of oral and oropharyngeal cancers. HPV DNA is found more often in cancers of the oropharynx (about one-third of cases) and especially the tonsils (about one-half of cases) and less often on oral cavity cancers. People with oral and oropharyngeal cancer linked with HPV infection are less likely to be smokers and drinkers. Oropharyngeal cancers that contain HPV DNA seem to have a better outlook than those without HPV. Most people with HPV infections of the mouth and throat have no symptoms and only a very small percentage develop oropharyngeal cancer.

Immune system suppression

People taking drugs that suppress the immune system to prevent rejection of transplanted organs or to treat certain immune system diseases may be at increased risk for cancers of the oral cavity and oropharynx.

Lichen planus

This is a disease that occurs mainly in middle-aged people. Most often it affects the skin (usually as an itchy rash), but it sometimes affects the lining of the mouth and throat, appearing as small white lines or spots. A severe case may slightly increase the risk of oral cancer.

Uncertain, unproven or controversial risk factors

Mouthwash

Some studies have suggested that mouthwash with high alcohol content might be linked to a higher risk of oral and oropharyngeal cancers. But recent research has questioned these results. Studying this possible link is complicated by the fact that smokers and frequent drinkers (who are already at increased risk of these cancers) are more likely to use mouthwash than people who neither smoke nor drink.

Irritation From Dentures

It has been suggested that long-term irritation of the lining of the mouth caused by poorly fitting dentures is a risk factor for oral cancer. But many studies have found no increased risk in denture wearers overall. Since poorly fitting dentures can tend to trap agents that have been proven to cause oral cancer, such as alcohol and tobacco particles, denture wearers should have them checked by a dentist regularly to ensure a good fit. All denture wearers should remove their dentures at night and clean and rinse them thoroughly every day.

Last Medical Review: 09/24/2009
Last Revised: 09/24/2009