The primary cause of skin cancer is exposure to the ultraviolet (UV) light which damages the DNA with repeated exposure. People with chronic exposure to UV light, whether in the outdoors or in tanning booths, are at increased risk of developing skin cancer. While normal skin cells grow, develop, and die in predictable cycles, skin cancer develops when skin cells grow out of control. Instead of dying, the damaged DNA within skin cancer cells causes them to continue growing and produce more abnormal cells. They also tend to invade other tissues. Skin cancer is the most common type of cancer in the US.
Types of Skin Cancer
The skin is made up of several types of cells which can be affected by distinct types of skin cancer. The three most common types of skin cancer, which together make up approximately 99% of diagnosed cases, are basal cell carcinoma, squamous cell carcinoma, and melanoma.
Basal Cell Carcinoma
As the most common type of skin cancer, basal cell carcinoma accounts for about 80% of all diagnosed skin cancers. It begins in the basal cells, which are skin cells located in the lowest layer of the epidermis. This type of cancer can look like a sore that doesn't completely heal, a shiny bump, or a reddish, irritated portion of the skin in an area that is exposed to the sun, such as the head, ears, face, shoulders and chest. It usually progresses slowly and does not tend to spread to other areas of the body (metastasize). Early detection and treatment can prevent basal cell carcinoma from spreading to surrounding tissue.
Squamous Cell Carcinoma
Potentially more aggressive than basal cell carcinoma, squamous cell carcinoma forms just beneath the surface of the skin in the squamous layer. While this second most common type of skin cancer often develops on sun-exposed areas, it can develop on other areas of the body like the mucous membranes and genitals. It often looks like a thick, rough, scaly patch or a bump. According to the The Skin Cancer Foundation, more than one million Americans are diagnosed annually with squamous cell carcinoma.
The most dangerous of the common forms of skin cancer is melanoma. While it accounts for only about 3% of skin cancer cases, melanoma is responsible for over 75% of skin cancer-related deaths. The Skin Cancer Foundation estimates that more than 9,700 people will die from melanoma in 2017. Melanoma originates in pigment-producing cells called melanocytes, which give the hair, skin, and eyes their color. Melanomas are usually black or brown, and often develop in a mole or take on the appearance of a new mole. If identified early, cure rates for melanoma are quite high. Once melanoma spreads to other parts of the body, cure rates are significantly reduced.
Treatment options for skin cancer include Mohs surgery, freezing (cryosurgery), scraping & burning, surgical removal (excision), and laser surgery.