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What You Must Know About Skin Cancer

2008-04-23来源:
What Is It?
Who's at Risk?
Symptoms
Treatment
Prevention Plan

Skin cancer rates are soaring in the United States. An American's lifetime risk of melanoma today is close to 1 in 75, while it was 1 in 5,000 in 1935. What's contributing to the increase? One possibility is that it's linked to the decline of outdoor occupations since the turn of the century. When people worked outdoors, they were continually exposed to the sun, so their skin was more accustomed to UV light and less susceptible to sunburn. Now people spend relatively little time in the sun. When they do, they tend to get sunburned, which increases their risk of skin cancer. Another theory is that more harmful solar radiation is reaching the earth today because of damage to the ozone layer of the atmosphere.

WHAT IS IT?
There are three common types of skin cancer. If detected early, all of them are curable. About 80 percent of skin cancers are basal cell or squamous cell carcinomas. Basal cell carcinomas are rarely fatal, but they can be disfiguring if they're not treated. Squamous cell carcinomas are more likely to be life-threatening.

Melanoma is the most lethal form of skin cancer. It can spread quickly to other parts of the body through the blood or lymph system. The five-year survival rate is 95 percent if melanoma is found early, but in its later stages, the disease is difficult to cure.

WHO'S AT RISK?
You're at increased risk for skin cancer if you have one or more of these risk factors:

Skin type and body characteristics. The most serious risks include having red or blond hair, light-colored eyes, fair skin that freckles or burns easily, and a large number of moles.

Ethnicity.White Americans are 10 times more likely to develop skin cancer than African Americans.

Age. The older you are, the greater your chance of developing skin cancer. The risk of melanoma increases sharply after age 50.

Family history. The risk of melanoma is greater if one or more of a person's close relatives (mother, father, brother, sister, child) have been diagnosed with melanoma.

Exposure to ultraviolet (UV) rays. Over 90 percent of skin cancers occur on skin that's regularly exposed to UV radiation from the sun or tanning lights.

Burns. You're at higher risk if you've had severe or blistering burns from sunlight, tanning beds or lamps, X rays, or radiation. Having been sunburned more than once as a child increases your risk for developing skin cancer as an adult.

Geography. You're at higher risk if you live in the South or at a high elevation.

SYMPTOMS

Basal cell carcinoma: painless smooth bump that grows slowly, often on the face, ear, or neck

Squamous cell carcinoma: painless reddish bump or patch that may form a crusted or scaly surface on the face, ears, neck, hands, or arms

Melanoma: painless dark bump or spot, a mole with an irregular shape and border, or a sore that doesn't heal, located anywhere on the body

TREATMENT
Treatment depends on the size, type, depth, and location of the cancer. Most people need surgery -- usually minor -- to remove skin cancers.

Surgery. Types include cryosurgery (tissue destruction by freezing), laser therapy (destruction with laser light), and electrodesiccation (destruction by heat). Some people with melanoma must have nearby lymph glands and large areas of skin removed as well.

Radiation therapy. Administration of high-dose, localized X rays to kill cancer cells.

Chemotherapy and biological therapy. Advanced melanoma is also treated with chemotherapy (anticancer drugs) or biological therapy (using the body's immune system to fight the cancer).

PREVENTION PLAN
Here are some steps you can take to reduce your risk:

Limit sun exposure. Stay out of the sun between 10 a.m. and 4 p.m., when UV rays are strongest.

Use sunscreen. Whenever you're outside, liberally apply a sunscreen with a sun protection factor (SPF) of at least 15, which blocks 93 percent of UV rays. Be sure the product contains avobenzone (or Parsol 1789) so you'll be protected against both types of sunlight -- UVA and UVB. Reapply every two hours to all exposed skin, including lips, bald spots, the part in your hair, and the tops of your ears -- common sites for skin cancer. For more information on sunscreen ingredients, click here.

Cover up. Wear tightly woven clothing outdoors, covering as much skin as possible. A broad-brimmed hat provides excellent protection. Be particularly careful if you're on snow, water, or ice, which intensify exposure.

Check yourself. Perform a monthly self-check, looking for new skin growths or changes in existing moles, freckles, or birthmarks.

These ABCDs describe suspicious moles:

Asymmetry: The mole is oddly shaped -- not symmetrical.
Border: It has irregular, notched, scalloped, or vaguely defined edges.
Color: Some areas may be darker than others, and more than one color -- tan, brown, black or even red, white or blue -- may be present.
Diameter: It's more than a quarter-inch in diameter (the size of a pencil eraser) or clearly becoming larger.

If you find any suspicious changes, see your doctor promptly. If you have a family history of melanoma, if you have many moles (especially on your trunk), or if you were sunburned regularly as a youth, see a dermatologist for an annual screening.