Some people with oral cancer do not have any known risk factors and others with several risk factors never develop the disease. Important risk factors are listed below.
About 90 percent of people with oral cancer use tobacco. The risk of developing these cancers increases with the amount smoked or chewed and the duration of the habit. Smokers are six times more likely than nonsmokers to develop these cancers. Smokeless tobacco ("snuff" or chewing tobacco) is associated with cancers of the cheek, gums and inner surface of the lips.
Drinking alcohol greatly increases a smoker's risk of developing oral cancer. About 75 percent to 80 percent of all patients with oral cancer drink alcohol.
People who drink alcohol but don’t smoke have a higher risk of cancer, if they are heavy drinkers. The combination of tobacco and alcohol is deadly. People who both smoke and drink have an even higher risk of developing a cancer in the mouth.
More than 30 percent of patients with cancers of the lip have outdoor occupations associated with prolonged exposure to sunlight.
A diet low in fruits and vegetables is associated with an increased risk of developing oral cancer.
Human papillomavirus (HPV) infection
The current studies indicate HPV may contribute to the development of oral cavity and oropharyngeal cancers in around 20 percent of people. This is the same virus that is now known to be linked to cervical cancer in women. There are about 42,000 cases of oral cancers diagnosed in the United States every year. The most common risk factor for these diseases is excessive alcohol use and cigarette smoking. But there is a new demographic emerging in people in their 30s, 40s, and 50s who don’t have these habits but have oral cancers, especially in males, often linked to HPV. This is a cancer that is hard to detect and difficult to see because it doesn’t cause a white plaque. HPV-positive cancers form in the back of the throat. The positive thing about these cancers is that they respond very well to treatment, better in fact than oral cancers that are not HPV-positive.
The likelihood of developing oral and pharyngeal cancer increases with age. Half of all cases are in persons older than age 65; 90 percent are older than age 45.