What does the skin do?
The skin is the largest organ of the body. It does many things, such as:
- Covers your internal organs and protects them from injury
- Serves as a barrier to germs
- Keeps you from losing too much water and other fluids
- Helps control your body temperature
- Protects the rest of your body from ultraviolet (UV) rays
- Helps your body make vitamin D
How common is skin cancer?
Skin cancer is the most common cancer. About 5.4 million basal and squamous cell skin cancers are diagnosed each year. (These are found in about 3.3 million Americans; some people have more than one.) Melanoma, the most deadly type of skin cancer, will account for about 76,380 cases of skin cancer in 2016.
Types of skin cancers
Skin cancer is by far the most common type of cancer. If you have skin cancer, it’s important to know which type you have because it affects your treatment options and your outlook (prognosis).
Basal and squamous cell skin cancers
These types of skin cancers start in the basal cells or squamous cells of the skin, which is how they get their names. These cells are in the outer layer of your skin.
Most basal and squamous cell cancers develop on sun-exposed areas of your skin, like the face, ears, neck, lips, and the backs of your hands.
Basal cell cancers tend to grow slowly and rarely spread to other parts of the body. Squamous cell cancers are more likely to grow into deeper layers of skin and spread, but this is not common.
Both basal cell and squamous cell skin cancers can be cured if found and treated early – when they are small and have not spread. But either type can cause problems if left untreated.
You can learn more about these skin cancers at Skin Cancer: Basal and Squamous Cell.
Melanoma skin cancer
Melanoma is a cancer that starts in melanocytes – the cells that make the brown skin pigment known as melanin, which gives skin its color. Melanin helps protect the deeper layers of the skin from sun damage.
Melanoma can start on nearly any part of the skin, even in places that aren’t normally exposed to the sun, like the genital or anal areas. Melanoma most often affects the skin (including under the nails), but it can also start in other parts of the body, such as in the eyes or mouth.
Melanoma is almost always curable when it’s found in very early stages. Melanoma accounts for only a small percentage of skin cancers, but it’s much more likely to grow and spread to other parts of the body, where it can be hard to treat. Because of this, melanoma causes most skin cancer deaths, accounting for more than 10,000 of the more than 13,650 skin cancer deaths each year.
You can learn more at Melanoma Skin Cancer.
Other types of skin cancer
There are many other types of skin cancer, such as Merkel cell carcinoma, skin lymphoma, Kaposi sarcoma, skin adnexal tumors, and sarcomas. These are all much less common than basal or squamous cell cancers or melanomas.
Skin cancer risk factors
Risk factors for skin cancer include:
- Too much exposure to ultraviolet (UV) radiation (from sunlight or tanning beds and lamps)
- Pale skin (easily sunburned, doesn’t tan much or at all, natural red or blond hair)
- Exposure to large amounts of coal tar, paraffin, arsenic compounds, or certain types of oil
- You or members of your family have had skin cancers
- Multiple or unusual moles
- Severe sunburns in the past
- Weakened immune system
- Older age (although melanomas are also found in younger people)
Signs and symptoms of skin cancer
Skin cancer can be found early, and you and your health care providers play key roles in finding skin cancer. Learn how to examine your skin for changes. If you have any of these symptoms, see a provider:
- Any change on your skin, especially in the size or color of a mole, growth, or spot, or a new growth (even if it has no color)
- Scaliness, roughness, oozing, bleeding, or a change in the way an area of skin looks
- A sore that doesn’t heal
- The spread of pigment (color) beyond its border, such as dark coloring that spreads past the edge of a mole or mark
- A change in sensation, such as itchiness, tenderness, or pain
To see some examples of different types of skin cancers, see our Skin Cancer Image Gallery.
Can skin cancer be prevented?
The best ways to help lower your risk of skin cancer is to stay out of intense sunlight and practice sun safety. You can still exercise and enjoy the outdoors while practicing sun safety at the same time. Here are some ways to be sun safe:
- Seek shade, especially in the middle of the day (between 10 am and 4 pm) when the sun’s rays are strongest. Teach children the shadow rule: If your shadow is shorter than you, the sun’s rays are at their strongest.
- Follow the Slip! Slop! Slap!® and Wrap! rules:
- on a shirt: Use protective clothing to cover as much skin as possible when you’re out in the sun. Choose comfortable clothes made of tightly woven fabrics that you can’t see through when held up to a light.
- on sunscreen: Use broad-spectrum sunscreen and lip balm with a sun protection factor (SPF) of 30 or higher. Apply a generous amount of sunscreen (about a palm full) to all unprotected skin. Reapply every 2 hours and after swimming, toweling dry, or sweating.
- on a hat: Cover your head with a wide-brimmed hat, shading your face, ears, and neck. If you choose a baseball cap, remember to protect your ears and neck with sunscreen.
- on sunglasses: Wear wrap-around sunglasses with 100% UVA and UVB absorption to protect your eyes and the nearby skin.
- doesn’t protect you from all UV rays. Do not use sunscreen as a way to stay out in the sun longer.
- these practices to protect your skin even on cloudy or overcast days. UV rays can travel through clouds.
- other sources of UV light. Tanning beds and sun lamps damage your skin and can cause cancer.
Last Revised: 04/13/2015