Locoa

SKIN CANCER
squamous cell carcinoma AND basal cell carcinoma
http://www.medicinenet.com/cancer/article.htm

Introduction
Skin cancer is the most common form of human cancer. It is estimated that over 1 million new cases occur annually. The annual rates of all forms of skin cancer are increasing each year, representing a growing public concern. It has also been estimated that nearly half ofall Americans who live to age 65 will develop skin cancer at least once.
The most common warning sign of skin cancer is a change in the appearance of the skin, such as a new growth or a sore that will not heal.
The term "skin cancer" refers to three different conditions. From the least to the most dangerous, they are:
* basal cell carcinoma (or basal cell carcinoma epithelioma)
*squamous cell carcinoma (the first stage of which is called actinic keratosis)
* melanoma

The two most common forms of skin cancer are basal cell carcinoma and squamous cell carcinoma. Together, these two are also referred to as nonmelanoma skin cancer. Melanoma is generally the most serious form of skin cancer because it tends to spread (metastasize) throughout the body quickly. Skin cancer isalso known as skin neoplasia. This article will discuss the two kinds of nonmelanoma skin cancer.
Basal cell carcinoma
What is basal cell carcinoma?
Basal cell carcinoma is the most common form of skin cancer and accounts for more than 90% of all skin cancer in the U.S. These cancers almost never spread (metastasize) to other parts of the body. They can, however, cause damage by growing andinvading surrounding tissue.

What are risk factors for developing basal cell carcinoma?
Light-colored skin, sun exposure, and age are all important factors in the development of basal cell carcinomas. People who have fair skin and are older have higher rates of basal cell carcinoma. About 20% of these skin cancers, however, occur in areas that are not sun-exposed, such as the chest, back, arms,legs, and scalp. The face, however, remains the most common location for basal cell lesions. Weakening of the immune system, whether by disease or medication, can also promote the risk of developing basal cell carcinoma. Other risk factors include
* exposure to sun. There is evidence that, in contrast to squamous cell carcinoma, basal cell carcinoma is promoted not by accumulated sun exposure butby intermittent sun exposure like that received during vacations, especially early in life. According to the U.S. National Institutes of Health, ultraviolet (UV) radiation from the sun is the main cause of skin cancer. The risk of developing skin cancer is also affected by where a person lives. People who live in areas that receive high levels of UV radiation from the sun are more likely todevelop skin cancer. In the United States, for example, skin cancer is more common in Texas than it is in Minnesota, where the sun is not as strong. Worldwide, the highest rates of skin cancer are found in South Africa and Australia, which are areas that receive high amounts of UV radiation.
* age. Most skin cancers appear after age 50, but the sun's damaging effects begin at an early age.Therefore, protection should start in childhood in order to prevent skin cancer later in life.
* exposure to ultraviolet radiation in tanning booths. Tanning booths are very popular, especially among adolescents, and they even let people who live in cold climates radiate their skin year-round.
* therapeutic radiation, such as that given for treating other forms of cancer.

What does basal cellcarcinoma look like?
A basal cell carcinoma usually begins as a small, dome-shaped bump and is often covered by small, superficial blood vessels called telangiectases. The texture of such a spot is often shiny and translucent, sometimes referred to as "pearly." It is often hard to tell a basal cell carcinoma from a benign growth like a flesh-colored mole without performing a biopsy. Some basal...