Skin cancer is often or usually caused by years of too much sun
exposure. More than 90% of all skin cancers are found on body parts that get
the most sun most of the time. The face, neck, ears, hands, and arms are common
body parts that get skin cancer.
Skin cancer can often be prevented by avoiding overexposure to the
sun's ultraviolet rays (UV rays). UV rays from artificial sources, such as
tanning beds or sunlamps, are just as dangerous as those from the sun.
The three main types of skin cancer are
basal cell cancer,
squamous cell cancer, and
melanoma.
The American Cancer Society uses the
ABCD
system
as a guide to detect signs of skin cancer in moles or growths on
the skin.
- Asymmetry. One half
doesn't match the other half.
- Border
irregularity. The edges are ragged, notched, or
blurred.
- Color. The pigmentation is not
uniform. Shades of tan, brown, and black are present. Dashes of red, white, and
blue add to the mottled appearance. Changes in color distribution, especially
the spread of color from the edge of a mole into the surrounding skin, also are
an early sign of melanoma.
- Diameter. The
mole or skin growth is larger than 6 mm (0.2 in.), or about the size of a
pencil eraser. Any growth of a mole should be of concern.
People with
skin types that burn easily and do not tan are at
highest risk for skin cancers. Anyone who has had severe sunburns or many
sunburns is at high risk for skin cancers.
A person in the southern United States has a 50% greater risk for
getting basal cell cancer than a person in the northern United States. The risk
for squamous cell cancer is four times greater in the southern U.S. The closer
a person is to the equator, the greater the cancer risk from sun exposure. The
risk for skin cancer also increases if you are exposed to intense sun year
after year over your lifetime.