Skin Cancer: non-melanoma and melanoma
The
skin is the body's largest organ. It protects against heat, light, injury, and
infection. It helps control body temperature. It stores water and fat. The skin
also makes vitamin D.
The
skin has three main layers:
-
Epidermis: The epidermis is the top layer of the
skin. It is mostly made of flat cells. These are squamous cells. Under the
squamous cells in the deepest part of the epidermis are round cells called
basal cells. Cells called melanocytes make the pigment found in skin and are
located in the lower part of the epidermis.
-
Dermis: The dermis is under the epidermis. It
contains blood vessels, lymph vessels, and glands. Some of these glands make
sweat, which helps cool the body. Other glands make sebum. Sebum is an oily
substance that helps keep the skin from drying out. Sweat and sebum reach the
surface of the skin through tiny openings called pores.
-
Hypodermis – which is fatty tissue
The
skin cancer is the cancer that forms in tissues of the skin.
When cancer arises from melanocytes it is called melanoma. When cancer arises
from cells that do not make pigment it may begin in basal cells or squamous
cells. Both types of skin cancer usually occur in skin that has been exposed to
sunlight, such as the skin on the face, neck, hands, and arms. But skin cancer
can occur anywhere.
Skin cancers are named for the type of cells that become cancerous.
Basal cell skin cancer grows slowly. It usually occurs on areas of the
skin that have been in the sun. It is most common on the face. Basal cell cancer
rarely spreads to other parts of the body.
Squamous cell skin cancer also occurs on parts of the skin that have been
in the sun. But it also may be in places that are not in the sun. Squamous cell
cancer sometimes spreads to lymph nodes and organs inside the body.
Risk Factors
Studies have found the following
risk factors for skin cancer:
- UV
radiation comes from the sun, tanning devices. A person's risk of skin cancer
is related to lifetime exposure to UV radiation. Most skin cancer appears after
age 50, but the sun damages the skin from an early age. UV radiation affects everyone. But people who
have fair skin that freckles or burns easily are at greater risk. These people
often also have red or blond hair and light-colored eyes. But even people who
tan can get skin cancer. People who live in areas that get high levels of UV
radiation have a higher risk of skin cancer. Also, people who live in the
mountains get high levels of UV radiation.
UV radiation is present even in cold weather or on a cloudy day.
- Scars
or burns on the skin
- Exposure
to arsenic at work
- Chronic
skin inflammation
- Diseases
that make the skin sensitive to the sun, such as albinism
- Radiation
therapy
- Medical
conditions or drugs that suppress the immune system
- Personal
or family history of skin cancers
The best way to prevent skin cancer is to protect yourself from the sun.
Also, protect children from an early age. Doctors suggest that people of all
ages limit their time in the sun and avoid other sources of UV radiation.
It is best to stay out of the midday
sun whenever you can. You also should protect yourself from UV radiation
reflected by sand, water, snow, and ice. UV radiation can go through light
clothing, windshields, windows, and clouds.
Wear long sleeves and long pants of tightly woven fabrics, a hat with a
wide brim, and sunglasses that absorb UV.
Use sunscreen lotions. Sunscreen lotions may help prevent skin cancer,
especially broad-spectrum sunscreen (to filter UVB and UVA rays) with a sun
protection factor (SPF) of at least 15. But you still need to avoid the sun and
wear clothing to protect your skin.
Symptoms
Most basal cell and squamous cell skin cancers can be cured if found and
treated early. A change on the skin is the most common sign of skin cancer.
This may be a new growth, a sore that doesn't heal, or a change in an old
growth. Not all skin cancers look the same. Sometimes skin cancer is painful,
but usually it is not. Checking your skin for new growths or other changes is a
good idea.
The most common skin cancer symptoms are:
- Small,
pale lump
- red
lump
- Sore
or lump that bleeds or develops a crust
- Flat
red spot that is dry may become itchy
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