The skin is the largest organ in the body. It protects the internal organs from ultraviolet rays, heat, injury and infection. It helps to control body temperature and stores water, fat and manufactures vitamin D. The skin has several layers, but the two main layers are the epidermis and the dermis. The epidermis is the upper an outer layer of the skin while the dermis is the low were or inner layer of the skin.
There are three types of skin cancer, all of which are made up of cells from the epidermis. The first is squamous cell carcinoma which is a thin flat tumor that forms on the top layer of the dermis. The second is basal cell carcinoma which are round cells under the squamous cell. And the third and most virulent is melanoma which is cancer of the melanocytes found in the lower part of the dermis. These melanocytes make melanin which is the pigments that gives us skin its natural color. When the skin is exposed to the sun the melanocytes make more pigment and cause the skin to darken.
The two most common kinds of skin cancer are basal cell carcinoma and squamous cell carcinoma. The term carcinoma means cancer that begins in the cells. Basal cell carcinoma accounts for more than 90% of all skin cancer in the United States. It is a slow-growing cancer that seldom spreads to other parts of the body. Squamous cell carcinoma also rarely spreads but it does so more often than basal cell cancer.
Basal cell carcinoma and squamous cell carcinoma are sometimes called nonmelanoma skin cancer. The third type of cancer, melanoma, that begins in the melanocytes is also the most aggressive.
Authors of a study from Mayo Clinic reviewed 1630 dermatology records from 1984 to 1992 and discovered 511 cases of squamous cell cancer. After plotting a trend of diagnoses the researchers found that these cancers tended to appear in the head, neck and upper extremities. This supported the theory that sun exposure was the causative factor in this form of cancer. (1)
Cancer of the skin is the most common of all cancers in the United States but it also accounts for less than 1% of all cancer deaths. Melanoma represents only 4% of all skin cancer but accounts for more than 75% of all deaths attributed to skin cancer.
Although exposure to the sun’s ultraviolet light is thought to be the most important factor in the cause of all skin cancers approximately 70% of American adults do not use sun protection. Sun protection is important not only while individuals are outside but also if they happened to work in an office where their desk is next to a window or if they spend any time driving in the car.
More than one million cases of nonmelanoma skin cancer are diagnosed each year. Both basal cell and squamous cell carcinoma, considered nonmelanoma, have a 95% cure rate when detected and treated early. Treatment of melanoma has a greater than 90% chance of cure when found and treated very early. However, if found after the growth has grown larger or metastasized a five-year survival rate drops dramatically to 50%.
The incidence of melanoma is 20 times higher for Caucasians then for people who have dark pigmented skin. Melanoma is more common than any non-skin cancer among women between 25 and 29 years of age.
Risk factors for any type of skin cancer includes lighter natural skin color, a family history of skin cancer, a personal history of skin cancer, exposure to the sun through work or play and a history of sunburns early in life. Skin that burns, freckles or reddens easily or individuals who have blue or green eyes or who have blonde or red hair will also have a higher risk of developing skin cancer than others.
In order to reduce the risk of developing skin cancer it’s important for individuals to also avoid the causative factors such as sun exposure, smoking and specific chemical toxins. Individuals who believe they may have skin cancer should be evaluated by their healthcare practitioner and treatment begun early in order to improve the chances of a cure.
(1) Archives of Dermatology: Trends in the Population-Based Incidence of Squamous cell Carcinoma
Skin Cancer Foundation: Skin Cancer Facts
Center for Disease Control and Prevention: Skin Cancer Statistics
Center For Disease Control and Prevention: Skin Cancer Rates by State
Cancer Research UK: Skin Cancer Incidence Statistics
American Academy of Dermatology: Skin Caner