Most skin cancers develop on the visible outer layer of the skin (the epidermis), particularly on sun-exposed areas like the face, head, hands, arms, and legs. In addition to sun exposure, family history may also play a role. Diagnosing skin cancer usually requires a skin biopsy, where a small piece of skin is removed for examination under a microscope. If skin cancer is detected before it has spread to surrounding tissues, chances of a complete cure are excellent.
Cancer develops when DNA, the molecule found in cells that encodes genetic information, becomes damaged and the body cannot repair the damage. These damaged cells begin to grow and divide uncontrollably. When this occurs in the skin, skin cancer develops. As the damaged cells multiply, they form a tumor. Since skin cancer generally develops in the epidermis, the outermost layers of skin, a tumor is usually clearly visible. This makes most skin cancers detectable in the early stages.
Skin Cancer Facts
- Skin cancer is the most common form of cancer in the United States. More than one million skin cancers are diagnosed annually.
- Each year there are more new cases of skin cancer than the combined incidence of cancers of the breast, prostate, lung and colon.
- One in five Americans will develop skin cancer in the course of a lifetime.
- Basal cell carcinoma (BCC) is the most common form of skin cancer; about one million of the cases diagnosed annually are basal cell carcinomas. Basal cell carcinomas are rarely fatal, but can be highly disfiguring.
- Squamous cell carcinoma (SCC) is the second most common form of skin cancer. More than 250,000 cases are diagnosed each year, resulting in approximately 2,500 deaths.
- Basal cell carcinoma and squamous cell carcinoma are the two major forms of non-melanoma skin cancer. Between 40 and 50 percent of Americans who live to age 65 will have either skin cancer at least once.
- About 90 percent of non-melanoma skin cancers are associated with exposure to ultraviolet (UV) radiation from the sun.
- Up to 90 percent of the visible changes commonly attributed to aging are caused by the sun.
- Contrary to popular belief, 80 percent of a person's lifetime sun exposure is not acquired before age 18; only about 23 percent of lifetime exposure occurs by age 18.
Types of Skin Cancer
Three types of skin cancer account for nearly 100% of all diagnosed cases (BCC, SCC and melanoma). Each of these cancers begins in a different type of cell within the skin, and each cancer is named for the type of cell in which it begins. Skin cancers are divided into one of two classes - nonmelanoma skin cancers and melanoma. Melanoma is the deadliest form of skin cancer.
The different types of skin cancer are:
- Basal cell carcinoma (BCC)
- Squamous cell carcinoma (SCC)
- Actinic Keratoses (pre-cancer)
- Atypical Nevus (pre-cancer)
- Mole (pre-cancer)
- Seborrheic Dermatitis (pre-cancer)
- Other nonmelanoma skin cancers: All other skin cancers combined account for less than 1% of diagnosed cases. These are classified as nonmelanoma skin cancers and include Merkel cell carcinoma, dermatofibromasarcoma protuberans, Paget's disease and cutaneous T-cell lymphoma.
The most common types of skin cancers are:
- Basal Cell Carinoma - (also called BCC) comes from the basal cells in lowest part of the epidermis. 80-85% of skin cancers are basal cell carcinomas.
- Squamous Cell Carcinoma - (also called SCC) comes from the skin cells (keratinocytes) that make up the top layers of the skin. About 10% of skin cancers are SCC. Skin cancer may often be preceded by lesions called pre-cancers. The most well-known of these lesions is called actinic keratosis (AK), an early stage of SCC.
- Melanoma - comes from skin cells called melanocytes, which create pigment called melanin that gives skin its color. 5% of all skin cancers are melanoma. Although less common, melanomas are a very dangerous type of skin cancer and are the leading cause of death from skin cancer.
Skin Cancer Rates are Rising
- While Americans now recognize that overexposure to the sun is unhealthy, the fact remains that most do not protect their skin from the sun's harmful rays. As a result, skin cancer is common in the United States. More than 1 million nonmelanoma skin cancers are diagnosed each year, and approximately one person dies from melanoma every hour.
- If current trends continue, 1 in 5 Americans will develop skin cancer during their lifetime. Melanoma continues to rise at an alarming rate. In 1930, 1 in 5,000 Americans was likely to develop melanoma during their lifetime. By 2004, this ratio jumped to 1 in 65. Today, melanoma is the second most common cancer in women aged 20 to 29.
Sun exposure is the leading cause of skin cancer. According to the American Cancer Society, "Many of the more than 1 million skin cancers diagnosed each year could be prevented with protection from the sun's rays." Scientists now know that exposure to the sun's ultraviolet (UV) rays damages DNA in the skin. The body can usually repair this damage before gene mutations occur and cancer develops. When a person's body cannot repair the damaged DNA, which can occur with cumulative sun exposure, cancer develops.
In some cases, skin cancer is an inherited condition. Between 5% and 10% of melanomas develop in people with a family history of melanoma.
- Ultraviolet radiation (UVR) is a proven human carcinogen, according to the U.S. Department of Health and Human Services.
- Frequent tanners using new high-pressure sunlamps may receive as much as 12 times the annual UVA dose compared to the dose they receive from sun exposure.
- Nearly 30 million people tan indoors in the U.S. every year; 2.3 million of them are teens.
- On an average day, more than one million Americans use tanning salons.
- Seventy one percent of tanning salon patrons are girls and women aged 16-29.
- First exposure to tanning beds in youth increases melonoma risk by 75 percent.
- People who use tanning beds are 2.5 times more likely to develop squamous cell carcinoma and 1.5 times more likely to develop basal cell carcinoma.
- The indoor tanning industry has an annual estimated revenue of $5 billion.
- A sore that comes and goes but never completely heals
- A shiny bump or nodule, especially if it appears pearly or translucent (these can look brown or reddish and resemble a mole)
- A slightly raised pink growth with a crusted depression in the center, possibly with tiny blood vessels (capillaries) visible on the surface
- A patch of skin that is red or irritated, especially on the chest, shoulders, or limbs
- A white or yellow-ish waxy scar with poorly defined borders
Prevention & Early Detection
The best protection against skin cancer is to minimize sun exposure and use a broad spectrum sunscreen. Avoid tanning beds. Cover yourself with sun-protective clothing. Examine your skin from head to toe once every month. See your dermatologist every year for a professional skin cancer exam.
- Sun protection can significantly decrease a person's risk of developing skin cancer. Sun protection practices include staying out of the sun between 10 a.m. and 4 p.m. when the rays are strongest, applying a broad-spectrum (offers UVA and UVB protection) sunscreen with a Sun Protection Factor (SPF) of 15 or higher year-round to all exposed skin, and wearing a protective clothing, such as a wide-brimmed hat and sunglasses when outdoors.
- Since skin cancer is so prevalent today, dermatologists also recommend that everyone learn how to recognize the signs of skin cancer, use this knowledge to perform regular examinations of their skin, and see a dermatologist annually (more frequently if at high risk) for an exam. Skin cancer is highly curable with early detection and proper treatment.
- Most skin cancer can be prevented by practicing sun protection, according to numerous research studies. Research also shows that not only does sun protection reduce one's risk of developing skin cancer; sun protection also may decrease the likelihood of recurrence.
- Even if you have spent a lot of time in the sun or developed skin cancer, it's never too late to begin protecting your skin. The American Academy of Dermatology (AAD) recommends that everyone protect their skin by following sun protection practices.
Several factors determine treatment of skin cancer, including the type, size, extent, location and number of lesions, as well as your medical and family history of skin cancers. Treatment options include: medications such as 5-fluorouracil and Imiquimod cream; curettage & desiccation; and excision or Mohs surgery. Radiation and chemotherapy may also be recommended.
Who gets skin cancer?
Skin cancer develops in people of all colors, from the palest to the darkest. However, skin cancer is most likely to occur in those who have fair skin, light-colored eyes, blonde or red hair, a tendency to burn or freckle when exposed to the sun, and a history of sun exposure. Anyone with a family history of skin cancer also has an increased risk of developing skin cancer. In dark-skinned individuals, melanoma most often develops on non-sun-exposed areas, such as the foot, underneath nails, and on the mucous membranes of the mouth, nasal passages, or genitals. Those with fair skin also can have melanoma develop in these areas.
- The majority of people diagnosed with melanoma are white men over age 50.
- Five percent of all cancers in men are melanomas; four percent of all cancers in women are melanomas.
- Contrary to popular belief, recent studies show that people receive a fairly consistent dose of ultraviolet radiation over their entire lifetime. Adults over age 40, especially men, have the highest annual exposure to UV.
- Between 1980 and 2004, the annual incidence of melanoma among young women increased by 50 percent, from 9.4 cases to 13.9 cases per 100,000 women.
- The number of women under age 40 diagnosed with basal cell carcinoma has more than doubled in the last 30 years; the squamous cell carcinoma rate for women has also increased significantly.
- Until age 39, women are almost twice as likely to develop melanoma as men. Starting at age 40, melanoma incidence in men exceeds incidence in women, and this trend becomes more pronounced with each decade.
- One in 41 men and one in 61 women will develop melanoma in their lifetime.
- Melanoma is one of only three cancers with an increasing mortality rate for men.