英語語言學(xué)習(xí)：皮膚癌

This is SCIENCE IN THE NEWS, in VOA Special English. I'm Doug Johnson.

And I'm Faith Lapidus. Today, we will tell about skin cancer.

Skin cancer is one of the most common forms of cancer. It is also the most deadly. America's National Cancer Institute reports that more than one million people in the United States developed skin cancer last year. Skin cancer is one of the easiest cancers to cure if found and treated early. When left untreated, however, it can lead to changes in a person's physical appearance and even death.

Skin cancer can affect anyone at any age. Former Presidents Ronald Reagan, Bill Clinton and George W. Bush all received treatment for skin cancer or pre-cancerous lesions. Doctors also treated Elizabeth Taylor, Cybill Shepherd and Melanie Griffith for skin cancer or early signs of it. All three performers survived.

Not everyone is so lucky. Musician Bob Marley died in nineteen eighty-one after melanoma spread in his body. Melanoma is the most severe form of skin cancer.

The main cause of skin cancer is ultraviolet radiation from the sun. Light and heat from the sun can change chemicals in the skin. Ultraviolet, also called U-V, rays cause the skin to burn. Over time, cancer could develop.

Anyone can get skin cancer. People with light-colored skin, hair or eyes are at greatest risk. A history of sunburn early in life also increases the risk. So does a family history of skin cancer.

Tanning beds can also produce high levels of U-V radiation. Many Americans think they look better when their skin is brown in color. They spend time in tanning beds in hopes to making their skin darker.

The two most common forms of skin cancer are basal cell and squamous cell cancers. They can develop as flat, discolored areas of skin or as raised growths, often with a rough surface.

Melanoma is far more dangerous. Melanomas can appear even in areas of skin that do not get a lot of sun. Malignant melanoma begins in body cells that produce a brown color. It usually first grows in a mole, a small dark area of skin. Melanoma often looks like a dark area with an unusual shape. It can be flat or raised. Other warning signs are a change in skin color and uneven borders around a mole.

The majority of people with melanoma are white men over the age of fifty. Without early treatment, this kind of cancer can spread quickly. Each year, more than sixty-eight thousand people in the United States learn they have melanoma. The National Cancer Institute estimates that eight thousand six hundred fifty Americans died because of melanoma last year.

The sooner skin cancer is found, the easier it is to treat. That is why doctors advise people to perform monthly exams of all areas of skin, from the top of the head to the bottom of the feet.

It is important to know early warning signs so that cancerous growths are found before they spread. The signs include a skin growth that changes in size, color, thickness or texture. Exams with a trained medical worker are also important. See a doctor if a mole bleeds, is bigger than six millimeters or you feel like rubbing it. If one or more of the warning signs are present, a doctor should examine you immediately.

Knowing what your skin looks like will help you recognize any changes. Some experts suggest taking pictures of moles and dating the images to compare over time.

Treatment of skin cancer depends on the kind, size, position on the body and depth of the growth, or tumor. Other considerations are the patient's age and general health. An operation to remove the cancerous cells can cure melanoma if the cancer has not spread.

Doctors use drugs to treat melanoma when it has already spread. They also may use radiation to kill cancer cells and reduce the size of cancerous growths. In addition, doctors now use treatments like gene therapy or remove affected fingers or toes. They also may use immunotherapy -- getting the body's immune system to fight the cancer.

Last month, researchers reported that an experimental drug improved survival in a study of melanoma patients. The drug, ipilimumab, worked by helping the body's natural defenses to fight cancer. Patients getting the drug lived on average for ten months compared to six months for those not getting it. Drug-maker Bristol-Myers Squibb hopes to get permission to sell ipilimumab by the end of the year.

America's Centers for Disease Control and Prevention says protection from the sun is important all year long, not just during the summer. It says ultraviolet radiation from the sun can reach you on cloudy days, as well as bright and sunny ones. During the summer, the most dangerous period for U-V rays in the United States mainland is between the hours of ten in the morning and four in the afternoon.

C.D.C. officials say U-V rays can damage your skin in as little as fifteen minutes. Sunglasses, hats and clothing offer some protection. Experts say the denser the material, the less radiation reaches the skin. Also, darker colors may offer more protection, and natural cotton blocks more than bleached, or whitened cotton. When clothing is wet or stretched, however, it lets more U-V rays pass through.

Choose to wear U-V ray-blocking sunglasses and sunscreen products. C.D.C. officials say people should put on sunscreen before they leave home, even on cloudy or cool days. Put a thick amount of sunscreen on all areas of skin exposed to the sun. Babies older than six months can wear sunscreen. Newborn babies should be kept out of the sun.

Doctors also suggest avoiding tanning salons and U-V tanning beds to prevent skin cancer. Each year, nearly thirty million people use indoor tanning beds in the United States. More than two million of them are young adults, between thirteen and eighteen years old. The Skin Cancer Foundation says use of tanning beds in youth increases a person's risk of developing melanoma by seventy-five percent.

Still, a study earlier this year found that most Americans think having darker skin is appealing and gives a healthy look. More than seven thousand American men and women took part in the study. Eighty percent of those questioned said they were concerned about skin cancer and believed it was important to protect themselves. At the same time, seventy-two percent believed people look better when their skin is tanned. And, about sixty percent mistakenly thought the sun was generally good for one’s health.

Another study involved more than four hundred college women who used tanning beds. The women were more likely to reduce their tanning for fear of looking older and developing wrinkled skin than fear of getting skin cancer. The women read information warning about skin cancer and the dangers of wrinkles. Later, the women recorded their tanning activity and feelings. Based on the results, researchers advised doctors and parents to warn young women about the risk of wrinkles as a more effective way to prevent tanning bed use.

Another report suggests that driving a vehicle on its left side increases the risk of developing skin cancer on the left side of the body. Scott Fosko is chairman of dermatology at Saint Louis University Medical School. He recently led a study of nearly nine hundred skin cancer patients. He found that more than half had skin cancer on the left side of their face or body. The percentage of men with skin cancer on their left side was even higher.

Doctor Fosko says this could have resulted from differences between the men and women. So, can driving with the windows up save your skin? Experts at the American Academy of Dermatology say no. They say modern automobile windshields block two kinds of ultraviolet radiation. But side windows generally block only one kind from reaching the driver or passengers. Mister Fosko suggests darkening windows or using sunscreen and protective clothing while driving.

So can you still enjoy sunny days without getting skin cancer? The answer is yes. However, you first must take the steps necessary to protect yourself and your family from the dangers of the sun.

This SCIENCE IN THE NEWS was written by Brianna Blake. June Simms was our producer. I'm Doug Johnson.

And I’m Faith Lapidus. Join us again next week for more news about science in Special English on the Voice of America.