All About Skin Cancer
While necessary to sustain life on Earth, the sun can also threaten
our health with its ultraviolet (UV) radiation. The skin is the
largest organ in the body. It covers and protects the organs inside
the body. It also protects the body against germs and prevents the
loss of too much water and other fluids. Skin Cancer is the cancer
that forms in skin tissues and usually occurs in skin that has been
exposed to sunlight, such as the skin on the face, neck, hands, and
arms.
Many believe that only lighter-skinned people need to be concerned about the effects of overexposure to the sun. Though it is true that darker skin has more natural pigment which acts as a natural skin protector, the skin is still susceptible to many of the damaging effects of UV radiation. The incidence of skin cancer is lower in dark-skinned people, but it still occurs and is often not detected until later stages when it is more dangerous.
What is Cancer?
Cancer
begins in cells, the building blocks of the body. Normally,
cells grow and divide to form new cells as the body needs them. When
cells grow old, they die, and new cells take their place.
Sometimes this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor, but not all tumors are cancer.
Benign
tumors are not cancerous. They are rarely life-threatening, can
usually be removed and they seldom grow back.
Malignant tumors are cancerous. They are generally more serious and may be life-threatening. Malignant tumors usually can be removed, but sometimes can grow back. Cells from malignant tumors can invade and damage nearby tissues and organs. Also, cancer cells can break away from a malignant tumor and spread through the body to form new tumors in other organs. [Top]
Types of Skin Cancer
Skin cancer is cancer cells that develop
in the skin’s tissue. Skin cancers are divided into melanoma and
non-melanomas. When cancer forms
in cells that make pigment, it is called melanoma. When cancer forms
in cells that do not make pigment, it may begin in basal cells
(small, round cells in the base of the outer layer of skin) or
squamous cells (flat cells that form the surface of the skin).
Melanoma
Melanoma is
the deadliest kind of skin cancer and one of the most common
cancers. This year, more than 59,000 Americans will learn that they
have melanoma.
Melanoma occurs when pigment cells become malignant. The pigment (melanin) in your skin determines the color of the upper layers of your skin. Melanin gives color to your skin, hair, and the iris of your eyes. Levels of melanin depend on race and amount of sunlight exposure. Sun exposure increases melanin production – your body’s way of trying to protect your skin against harmful UV rays. The increased production of melanin leads to "tanned" or burned skin.
Most pigment cells are in the skin, but some melanomas occur in the eye and may occur in other parts of the body. In males, melanoma is often found on the trunk (the area between the shoulders and the hips) or the head and neck. In females, it often develops on the lower legs. Melanoma is less common in darker skinned people, but when it develops it tends to occur under the fingernails or toenails, or on the palms or soles.
Melanoma is curable when discovered in its early stages. But it is also likely to spread to other parts of the body.
Non-Melanomas
There are many types of non-melanoma skin cancer, but the two most common are basal cell carcinoma and .
About 3 out of 4 skin cancers are
basal cell carcinomas. They usually begin on areas exposed to
the sun such as the head and neck. Basal cell carcinoma was once
found mostly in middle-aged or older people. Now it is also being
seen in younger people, perhaps because people are spending more
time in the sun with their skin exposed.
Basal cell carcinoma grows slowly. It is highly unusual for a basal cell cancer to spread to distant parts of the body. But if it is not treated, it can grow into nearby areas and invade the bone or other tissues beneath the skin. After treatment, basal cell carcinoma can come back (recur) in the same place on the skin. Also, new basal cell cancers can start elsewhere on the skin. Often, people who have one basal cell cancer will develop a new skin cancer within the next 5 years.
Squamous cell carcinoma
accounts for about 2 out of 10 skin cancers. It usually appears on
places of the body such as the face, ears, neck, lips, and back of
the hands. It can also begin within scars or skin ulcers elsewhere
on the body. Less often, it forms in the skin of the genital area.
Squamous cell carcinomas are more likely to invade fatty tissues just beneath the skin, and are slightly more likely to spread to lymph nodes or distant parts of the body than are basal cell carcinomas.
There are also several other, much less common, types of non-melanoma skin cancers. These account for less than 1% of non-melanoma skin cancers. [Top]
Who is at Risk?
We do not yet know exactly what causes skin cancer, but we do know that certain risk factors are linked to the disease. A risk factor is anything that increases a person's chance of getting a disease such as cancer. Studies have found that the greatest risk factor for skin cancer is UV radiation.
Too much exposure to UV radiation is a risk factor for melanoma or other skin cancers. The main source of such radiation is sunlight. Tanning lamps and booths are another source. A person's risk of skin cancer is related to lifetime exposure to UV radiation.
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 have darker skin or those who “tan easily” can get skin cancer.
People who live in areas that get high levels of UV radiation have a higher risk of skin cancer. In the United States, areas in the south (such as Texas and Florida) get more UV radiation than areas in the north (such as Minnesota). 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. [Top]
Statistics and Facts
Cancer of the skin (including melanoma and non-melanoma skin cancers) is the most common of all cancers. It accounts for about half of all cancers.
Melanoma accounts for about 3% of skin cancer cases, but it causes most skin cancer deaths. The number of new cases of melanoma in the United States is on the rise. The American Cancer Society estimates that in 2007 there will be 59,940 new cases of melanoma in this country. About 8,110 people will die of this disease.
The National Cancer Institute estimates more than 1,000,000 new cases of non-melanomas in the U.S. in 2007 with less than 2,000 deaths from the disease. [Top]