Lip Cancers Health Article

Definition

Lip cancer is a malignant tumor, or neoplasm, that originates in the surface layer cells of the epithelial tissue in the upper or lower lip.

Description

The upper and lower lips are the well-defined red (often called vermilion) areas that surround the opening to the mouth. They contain muscles and special cells (receptors) that are sensitive to heat and cold and feeling. Largely taken for granted, the lips are important in identifying types of food to the brain and in getting food into the mouth. Lips also play a crucial role in speech.

A malignant tumor, or neoplasm, that originates in the cells of one of the lips is a cancer of the lip. Lip cancer almost always begins in the flat, or squamous, epithelial cells. Epithelial cells form coverings (tissues) for the surfaces of the body. Skin, for example, has an outer layer of epithelial tissue.

If a part of the lip is affected by cancer and must be removed by surgery, there will be significant changes in eating ability and speech function. The more lip tissue removed, the greater the disturbances to the normal patterns of talking and eating.

Demographics

Nine out of ten cases of lip cancer are diagnosed in people over the age of 45. Age, or the aging process, may contribute to the way the cancer develops. As a line of cells gets older, the genetic material in a cell loses some of its ability to repair itself. When the repair system is operating normally, damage to the genetic material, or DNA, caused by ultraviolet light from the sun is quickly weeded out. When the system fails, changes in the genetic material are kept, and they multiply when a cell divides.

If the genetic material cannot repair itself, damage caused by exposure to environmental factors such as sunlight and chemicals can quickly set in motion the uncontrolled growth of cells.

The effects of factors that are known to cause lip cancer, such as smoking and exposure to sunlight, also add up as a person ages. Thus, the combination of a breakdown in the repair system in the genetic material and the considerable periods of time (decades) over which a person is exposed to cancer agents probably causes lip cancers. However, researchers are still investigating how lip cancers start.

Men are at greater risk for lip cancer than women. Depending on where they live, men are two or three times more likely to be diagnosed than women. Fair-skinned people are more likely to get lip cancer than those with dark skin. For reasons not yet understood, people in Asia have a much lower risk of lip cancer than those living on other continents. In many parts of Asia, lip cancer is extremely rare. In North America, nearly 13 out of 100, 000 men will be diagnosed with lip cancer during their lifetime. In Australia, about 13.5 men per 100, 000 will be diagnosed.

The frequency of lip cancer is often lumped together with oral cancer, although lip cancer is probably much more like skin cancer in origin. There are about 30, 000 new diagnoses of mouth and lip cancer in the United States each year.

In some places, such as South Australia, women are experiencing a striking increase in lip cancer diagnoses. There are several theories to explain the trend. Among them, perhaps fewer women regularly wear hats, which offer protection from the sun. Women might also be for-going lipstick, which serves as another barrier to sunlight.