Skin Cancer




Cancer is a word used to describe a group of diseases. Each has its own

name, its own treatment, and its own chances of being cured. Each is

different from the others in many ways, but every cancer, whatever its called

or whatever part of the body it is located in, is a disease of the body’s

cells. The millions of tiny cells that make up the human body are so small

that they can be seen only by looking through a microscope. There are

different kinds of cells, but they all make new cells by dividing into two.

This is how worn-out, old cells are replaced with strong new ones. When a

cell changes and doesn’t do the job it should do for the body, it divides into

more cells like itself, then these cells keep dividing into more cells. A

group of these cells is a tumor. There are two kinds of tumors. A benign

tumor is not cancer. The cells of a benign tumor can crowd out healthy cells,

but they cannot spread to other parts of the body. A malignant tumor is

cancer. Like a benign tumor, it can take over other healthy cells around it,

but it can also spread to other parts of the body. To do this, a cell or

group of cells from the tumor breaks away and moves, usually though the blood,

to other parts of the body. There they divide and start tumors made of

malignant cells like the ones that made up the first tumor. When this

happens, it is called metastasis.

Skin cancer is the most prevalent of all cancers, and it’s increasingly

common. About a million Americans will develop skin cancer this year. It is a

disease in which cancer cells are found in the outer layers of skin. Skin

protects the body against heat, light, infection, and injury. It also stores

water, fat, and vitamin D.

The skin has two main layers and several kinds of cells. The top layer of

skin is called the epidermis. It contains three kinds of cells: flat, scaly

cells on the surface called squamous cells, round cells called basal cells,

and cells called melanocytes, which give skin its color.

The inner layer of skin is called the dermis. This layer is thicker, and

contains blood vessels, nerves, and sweat glands. The hair on skin also grows

from tiny pockets in the dermis, called follicles. The dermis makes sweat,

which helps cool the body, and oils that keep the skin from drying out.

Skin cancer is viewed as an undeclared epidemic by dermatologists. "Skin

cancer is now about as common as all other cancers combined," says Martin A.

Weinstock, M.D., Ph.D., director of Brown University’s Dermatoepidemiology

Unit and Chief of Dermatology at the Providence Veteran’s Affairs Medical

Center. He also says there’s no evidence the epidemic has peaked, which means

it could get worse.

Skin cancer is quite curable when treated early. More than ninety percent of

skin cancers are completely cured. It’s also largely preventable, simply by

avoiding sun and sunlamp exposure.

Sunscreen is the most common defense against skin cancer. However, only two

in five people consistently use sunscreen whenever they’re in the sun. Few

people say they sunbathe, but about one in five adults still does.

There are three main types of skin cancer. Melanoma is the least common but

most serious because this killer is responsible for three-quarters of the

nearly 10,000 skin cancer deaths per year. The other two types, basal cell

and squamous cell carcinomas, are often referred to together as non-melanoma

skin cancer. Basal cell cancer is by far the most common skin cancer,

followed by squamous cell carcinoma, which can also become a killer. Between

1980 and 1989, the incidence of non-melanoma skin cancers increased sixty-five

percent and melanoma twenty-one percent. Skin cancer is also striking at

younger ages than before. One-quarter of the more than 30,000 people expected

to develop melanoma this year will be thirty-nine or younger. Other kinds of

cancers that may affect the skin include cutaneous T-cell lymphoma, a cancer

of the lymph system, and Kaposi’s sarcoma.

Melanoma is the fastest-growing type of cancer, affecting about 32,000

Americans in 1993. The skin cancer is triggered by UV rays from the sun and

is signaled by the growth or appearance of an irregular more. If caught

early, melanoma is completely curable with the mole’s removal. However, the

cancer can and will spread if not caught early.

Developing skin cancer is at least a two-step process, involving initiation

and promotion of malignant growth. Studies have shown that UV harms a

mechanism for repairing cell damage. Once the repair system is impaired,

cells become increasingly vulnerable to injury. Subsequent UV exposures make

it worse, and can initiate malignancy. After UV exposure, the repair

mechanism normally directs damaged cells to commit suicide. That is why skin

peels after a sunburn. However, previously damaged cells with a

malfunctioning repair system escape this process. Genetic damage accumulates

as normal cells die and abnormal ones survive. It’s been determined that skin

does not have to be burned to be damaged, and such damage accumulates with

chronic, everyday exposure.

Two types of UV radiation reach the earth, UVA and UVB. Both contribute to

skin damage, including skin cancer. There are no "safe" UV rays. But the SPF

sunscreen numbering system was devised as a guide to protect against sunburn,

which is caused mostly by UVB rays. Because sunscreens allow one to stay out

in the sun longer without burning, exposure to UVA rays is increased, and many

sunscreens don’t protect against these rays.

While sunscreens protect against sunburn, they don’t necessarily prevent

cancer. If one uses sunscreens to spend more time in the sun, the skin could

collect about the same total exposure to damaging radiation. This is why it’s

still a good idea to stay out of the sun at midday and to wear protective

clothing and hats.

Some studies estimate that diet may be involved in forty to sixty percent of

all cancers. A high fat intake increased the likelihood of skin cancer after

exposure to UV radiation, while switching to a low-fat diet after exposure

reduced the incidence of skin cancer. The National Academy of Sciences

recommends a diet in which thirty percent or less of the calories come from

fat. The National Cancer Institute, the American Cancer Society, the American

Heart Association, and other health organizations support this recommendation.

Once cancer develops, early detection and treatment are the best defense.

Those with blonde or red hair should be especially vigilant. Self-exams are

recommended, and any growth, mole, or discoloration that appears suddenly or

begins to change, or any sore that appears and doesn’t heal should be brought

to a doctor’s attention. Characteristics of cancerous moles are asymmetry,

ragged edges, bleeding, itching or pain.

Skin cancer is more common in people with light colored skin who have spent a

lot of time in the sunlight. Skin cancer can occur anywhere on the body, but

it is most common in places that have been exposed to more sunlight, such as

the face, neck, hands, and arms.

Skin cancer can look many different ways. The most common sign of skin

cancer is a change on the skin, such as a growth or a sore that won’t heal.

Sometimes there may be a small lump. This lump can be smooth, shiny and waxy

looking, or it can be red or reddish brown. Skin cancer may also appear as a

flat red spot that is rough or scaly. Not all changes in the skin are cancer,

but all changes should be brought to the attention of a doctor.

For any type of skin cancer, treatment involves removing the lesion, usually

in an outpatient procedure. The treatment goal is to remove or destroy the

growth completely with as little damage as possible to healthy tissue.

Doctors evaluate numerous factors in planning treatment. Considerations

include type of cancer, tumor size and location, extent of disease, whether

it’s new or recurrent, potential for scarring, and the patient’s overall

health.

Types of surgery include cryosurgery (destruction by freezing), laser

surgery, and cuttrettage and electrodessication (using a spoon-like blade to

scoop out the growth, followed by destruction of surrounding tissue with

electric shock).

Chemotherapy uses drugs to kill cancer cells. In treating skin cancer,

chemotherapy is often given as a cream or lotion placed on the skin to kill

cancer cells. Chemotherapy may also be taken by pill, or it may be put into

the body by a needle in a vein or muscle. Chemotherapy given in this way is

called a systemic treatment because the drug enters the bloodstream, travels

through the body, and can kill cancer cells outside the skin.

Biological therapy tries to get the body to fight cancer on its own. It uses

materials made in the body or in a laboratory to boost, direct, or restore the

body’s natural defenses against disease.

Even after successful treatment, people who have had skin cancer remain at

increased risk of developing it again. Protecting their skin from UV exposure

is critical in helping to prevent a recurrence. It should become a life-long

habit.