What is skin cancer?
Skin cancer is the most common form of cancer in the United States. The two most common types of skin cancer—basal cell and squamous cell carcinomas—are highly curable, but can be disfiguring and costly to treat. Melanoma, the third most common skin cancer, is more dangerous and causes the most deaths. The majority of these three types of skin cancer are caused by overexposure to ultraviolet (UV) light.
Ultraviolet (UV) Light
Ultraviolet (UV) rays are an invisible kind of radiation that comes from the sun, tanning beds, and sunlamps. UV rays can penetrate and change skin cells.
The three types of UV rays are ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC)—
- More UVA rays reach the earth’s surface than the other types of UV rays. UVA rays can reach deep into human skin, UVA rays can damaging connective tissue and the skin’s DNA.
- Most UVB rays are absorbed by the ozone layer, so fewer of them reach the earth’s surface compared to UVA rays. UVB rays, which help produce vitamin D in the skin, don’t reach as far into the skin as UVA rays, but they can still cause sunburn and damage DNA.
- UVC rays are very dangerous, but they are absorbed completely by the ozone layer and do not reach the earth’s surface.
In addition to causing sunburn, too much exposure to UV rays can change skin texture, cause the skin to age prematurely, and can lead to skin cancer. UV rays also have been linked to eye conditions such as cataracts.
What are the risk factors for skin cancer?
People with certain risk factors are more likely than others to develop skin cancer. Risk factors vary for different types of skin cancer, but some general risk factors are having—
- A lighter natural skin color.
- Family history of skin cancer.
- A personal history of skin cancer.
- Exposure to the sun through work and play.
- A history of sunburns, especially early in life.
- A history of indoor tanning.
- Skin that burns, freckles, reddens easily, or becomes painful in the sun.
- Blue or green eyes.
- Blond or red hair.
- Certain types and a large number of moles.
Tanning and Burning
Ultraviolet (UV) rays come from the sun or from indoor tanning (using a tanning bed, booth, or sunlamp to get tan). When UV rays reach the skin’s inner layer, the skin makes more melanin. Melanin is the pigment that colors the skin. It moves toward the outer layers of the skin and becomes visible as a tan.
A tan does not indicate good health. A tan is a response to injury, because skin cells signal that they have been hurt by UV rays by producing more pigment.
People burn or tan depending on their skin type, the time of year, and how long they are exposed to UV rays. The six types of skin, based on how likely it is to tan or burn, are—
- Always burns, never tans.
- Burns easily, tans minimally.
- Burns moderately, tans gradually to light brown.
- Burns minimally, always tans well to moderately brown.
- Rarely burns, tans profusely to dark.
- Never burns, deeply pigmented, least sensitive.
Although everyone’s skin can be damaged by UV exposure, people with skin types I and II are at the highest risk.
What can I do to reduce my risk of skin cancer?
- Stay in the shade, especially during midday hours.
- Wear clothing that covers your arms and legs.
- Wear a hat with a wide brim to share your face, head, ears and neck.
- Wear sunglasses that wrap around and block both UVA and UVB rays.
- Use sunscreen with a SPF factor
- Avoid indoor tanning
What are the symptoms of skin cancer?
A change in your skin is the most common sign of skin cancer. This could be a new growth, a sore that doesn’t heal, or a change in a mole. Not all skin cancers look the same.
A simple way to remember the signs of melanoma is to remember the A-B-C-D-Es of melanoma—
- “A” stands for asymmetrical. Does the mole or spot have an irregular shape with two parts that look very different?
- “B” stands for border. Is the border irregular or jagged?
- “C” is for color. Is the color uneven?
- “D” is for diameter. Is the mole or spot larger than the size of a pea?
- “E” is for evolving. Has the mole or spot changed during the past few weeks or months?
Talk to your doctor if you notice changes in your skin such as a new growth, a sore that doesn’t heal, a change in an old growth, or any of the A-B-C-D-Es of melanoma.
What screening tests are there?
The U.S. Preventive Services Task Force (USPSTF) has concluded there is not enough evidence to recommend for or against routine screening (total body examination by a doctor) to find skin cancers early. This recommendation is for people who do not have a history of skin cancer and who do not have any suspicious moles or other spots. Report any unusual moles or changes in your skin to your doctor. Also talk to your doctor if you are at increased risk of skin cancer.