The National Cancer Institute, NCI, groups cancers of the lip with other oral cancers that arise on the front two-thirds of the tongue, inside the cheeks, under the tongue, on the hard palate and in the little space behind the innermost teeth. These areas share the same kind of lining, called squamous epithelium. Thus, cancers arising in these areas share certain properties; they are usually squamous carcinomas.
The actual cause of oral cavity cancers, including lip cancer, is not known, but certain risk factors are associated with their development.
Tobacco Use
According to the American Cancer Society, ACS, about 80 percent of all patients with mouth cancers use one form of tobacco or another. Lip cancers are linked specifically to pipe smoking. Cancer on the inner parts of the lips and cheeks is linked to chewing tobacco and snuff. Those who have been cured of cancer are more than three times more likely to develop a second cancer if they continue to use tobacco, compared to those who stop using tobacco, reports the ACS.
Alcohol Use
Heavy drinking also increases the risk of oral cancers, including lip cancer. According to the ACS, up to 70 percent of people with oral cancer are heavy drinkers. Alcohol also appears to heighten the risk of oral cancer in smokers. The risk of oral cancer is thought to be up to 100 times greater in smokers who drink than in the normal population.
Gender
Men are much more likely to develop cancer of the lips than women. The fact that more men than women drink heavily and smoke is cited by the ACS as a possible explanation for the gender differences.
Exposure To Sunlight
According to the Mayo Clinic, excessive sun exposure of the lips is a possible risk factor for cancer of the lips. The ACS notes that this kind of cancer is more common among people with outside jobs. The ultraviolet rays in sunlight cause the skin changes that predispose people to the development of cancer.
Poor Nutrition And Diet
A diet lacking in fruits and vegetables and in vitamin A is linked with a higher occurrence of oral cancers, according to the American Society of Clinical Oncology. Chewing betel nuts is another risk factor.
Other Possible Causes
The American Society of Clinical Oncology reports that people over age 45 are at increased risk for oral cancer. The use of dentures is another possible factor in the development of oral cancers. According to the ACS, people with human papilloma virus or HPV infection, and those with depressed immunity as seen in HIV/AIDS, are all more likely to develop cancer of the lips. Other suspected factors include fair skin, previous head and neck irradiation, alcoholic mouth washes and the presence of a skin disease called lichen planus.
