Causes, risk factors and prevention
What causes oral cancer?
The main causes of oral cancer include:
- Tobacco use (90 percent of people with oral cancers use tobacco by smoking cigarettes, cigars, pipes, chewing tobacco and dipping snuff).
- Alcohol use.
Other causes of oral cancer may include:
- Leukoplakia – a condition characterized by a whitish patch that develops inside the mouth or throat.
- Erythroplakia – a condition characterized by a red, raised patch that develops inside the mouth.
- Excessive sun exposure, which, like elsewhere on the body, can cause cancer on the lip.
What are the risk factors for oral cancer?
Although heredity also plays a factor, certain lifestyle habits and health conditions can increase a person’s risk for developing oral cancer. These include, but are not limited to, the following:
The majority of patients with oral cancer (90 percent) use tobacco in one form or another. Tobacco can damage cells in the lining of the oral cavity and oropharynx, causing abnormal cells to grow more rapidly to repair the damage. Researchers believe that the DNA-damaging chemicals in tobacco are linked to the increased risk of oral cancer, according to the American Cancer Society.
The majority of patients with oral cancer (75 to 80 percent) use alcohol frequently. Paired with tobacco use, patients who drink and smoke increase their risk of developing oral cancer even more. Researchers have found that alcohol increases the penetration of DNA-damaging chemicals in the lining of the oral cavity and oropharynx, according to the American Cancer Society.
Prolonged exposure to ultraviolet radiation from the sun can cause skin cancer. People who are outdoors for an extended period of time increase their risk of lip cancer, as well. More than 30 percent of lip cancer diagnoses are in persons with outdoor occupations.
Chronic irritation to the lining of the mouth, due to poorly fitting dentures or other reasons, may increase a person’s risk for oral cancer.
Lack of fruits and vegetables in diet
Research has suggested that fruits and vegetables, which contain antioxidants that can “trap” harmful molecules, can decrease the risk for oral cancer (and other cancers). Thus, it is speculated that persons with a low intake of these types of foods are at an increased risk for (oral) cancer.
Some studies have shown that mouthwash with alcohol content increases the risk for oral cancer. In addition, other studies have shown that smokers and people who drink alcohol tend to use mouthwash more often, linking all three factors together.
Human papillomavirus (HPV) infection
HPV usually causes warts and has been linked to cervical, vaginal and penile cancers. HPV also may increase the risk for oral cancers.
Oral cancer is twice as common in men than in women, partly because men are more likely to use tobacco and alcohol.
It is important to detect oral cancer as early as possible, because treatment works best before the disease has spread. The National Cancer Institute and American Cancer Society encourage people to take an active role in the early detection of oral cancer by performing monthly self-examinations. Take special note of any red or white patches, lumps or thickening of skin, tissue or gums, a sore that either does not heal properly (after a one- to two-week period), or a sore that tends to bleed easily or excessively. In addition, be sure to take note of a persistent sore throat, hoarseness or difficulty maneuvering the jaw during chewing or swallowing. Be sure to consult your physician right away if any of these symptoms are present.
The Oral Health Education Foundation recommends the following steps when examining your mouth.
- Remove any dental products in the mouth.
- Visually look and touch your mouth, including the lips and gums.
- Check the roof of your mouth.
- Check the inside of the cheeks and the back gums.
- Check the tongue, including the sides and underneath.
- Check for enlarged lymph nodes in the neck and under the jaw.
Regular dental checkups that include an examination of the entire mouth also are important in the early detection of oral cancer or precancerous conditions. Your physician also should check your mouth as part of a routine physical exam.
What is the link between tobacco and oral cancer?
Tobacco use is a known as a major risk factor for oral and other cancers. All tobacco products, including cigarettes, cigars, pipe tobacco, chewing tobacco and snuff, contain toxins (poisonous substances), carcinogens (cancer-causing agents) and nicotine (an addictive substance). Each tobacco product is linked to an increased risk for specific cancers:
Cigarettes, the most common form of tobacco used, cause 87 percent of all lung cancer cases, according to the American Lung Association. In addition, smokers are six times more likely than nonsmokers to develop some form of oral cancer in the oral cavity. Cigarettes contain more than 43 cancer-causing agents.
Cigars and pipes
Cigars and pipes are often perceived as the less harmful way to smoke tobacco. However, even when not inhaling, cigar and pipe smokers are at increased risk for cancer of the oral cavity and lungs. Pipe smokers also are at increased risk for lip cancers in areas where the pipestem rests. In addition, cigars take longer to burn and contain more tobacco than cigarettes, increasing the amount of secondhand smoke exposure.
Chewing tobacco and snuff
Spit tobacco, also known as chewing tobacco and snuff, are forms of tobacco that are put between the cheek and gum. Chewing tobacco can be in the form of leaf tobacco (which is packaged in pouches) or plug tobacco (which is packaged in “brick” form). Snuff is a powdered form of tobacco, usually sold in cans. The nicotine is released from the tobacco as the user “chews.”
Chewing tobacco and snuff can cause cancer in the cheek, gums and lips. Like a pipe, cancer often occurs where the tobacco is held in the mouth. Cancer caused by “smokeless” tobacco often begins as leukoplakia (a condition characterized by a whitish patch that develops inside the mouth or throat) or erythroplakia (a condition characterized by a red, raised patch that develops inside the mouth). Other problems associated with chewing tobacco and snuff include periodontal disease, tooth discoloration and bad breath, among others.
How do cigarettes and cigars compare?
Cigars became a trend in the 1990s, attracting the young and the old. Although perceived as less detrimental to one’s health, cigars actually pose the same risk as cigarettes for oral cancer. Although many cigar smokers do not inhale, the risk for oral, throat, and esophageal cancers is the same as for cigarette smokers. Consider these facts:
- Compared with nonsmokers, cigar smokers are four to 10 times more likely to develop oral cancer, esophageal cancer and laryngeal cancer.
- Cigar smokers may spend an hour or more smoking one large cigar which can contain the same amount of nicotine as a full pack of cigarettes. Furthermore, even unlit cigars, when held in the mouth for an extended period of time, promote nicotine absorption.
- Secondhand smoke from cigars contain toxins and cancer-causing agents (carcinogens) similar to secondhand cigarette smoke, but in higher concentrations.
Quitting tips for persons who use tobacco products
The American Academy of Otolaryngology and the American Lung Association offer the following tips to persons who use tobacco products and are trying to quit:
- Think about why you want to quit.
- Pick a stress-free time to quit.
- Ask for support and encouragement from family, friends and colleagues.
- Start doing some exercise or activity each day to relieve stress and improve your health.
- Get plenty of rest and eat a well-balanced diet.
- Join a stop-smoking program, or other support group.