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June 1, 2011

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Home » Feature » Health and Environment

Moles common, melanoma rare

LONG-TIME exposure to sunlight can cause skin cancer, including melanoma, which is malignant and can be fatal if it spreads below the skin. Some moles (nevus) also can be or can turn cancerous; they should be checked periodically.

Earlier this year there was a rush of fearful people asking doctors about their moles and asking for removal, says Dr Li Yongmei, chief of dermatology at Longhua Hospital attached to Shanghai University of TCM.

They were prompted by the film "If You Are the One 2, " in which a character dies of skin cancer that developed from a mole.

Li and others say there's no need to remove most moles.

Though about 60 percent of melanoma cases develop from moles, not every mole turns into melanoma. Moles that are raised are usually harmless.

In China the rate of melanoma is only 0.4-0.5 out of 100,000, says Dr Li Tao, associate chief of surgery at Zhejiang Tumor Hospital. Environmental pollution has contributed to a higher rate, but it's still far less than other cancers in China, he says.

"Nevus (various kinds of moles) are just common marks and most are not harmful, says Dr Li Yongmei of Longhua Hospital. Almost everybody has them, more as they age.

There are three types of nevus - marginal, intradermal and compound. The most dangerous is the marginal nevus that grows between the epidermis and dermis; the intradermal nevus that bulges (and sometimes has a hair growing from it) and compound nevus are less likely to become malignant.

"Repeated stimulation like rubbing raises the risk of malignancy greatly," say Dr Li Yongmei. "That's why moles on the palm and sole of the foot are at the top of the list for removal."

She also suggests removing moles on the scalp that can be irritated by combing or brushing hair. Avoiding direct exposure to sunshine and avoid hormone medication, she recommends.

"A nevus with a clear outline and even color is usually healthy and there's nothing to worry about," says Dr Li Yongmei. "But sudden changes in a mole, including size, shape and color are warning signs of malignancy and surgical removal is usually necessary."

Warning signs also include bleeding, ulceration, pain and eruption of small "satellite" nevus.

Melanoma is not incurable, according to Dr Li Yongmei, especially when surgically removed in the early stages when it is growing horizontally. Laser surgery is not helpful. "Laser surgery just burns the surface but the sick roots may still be there. Laser burning can also push the cancer cells to a deeper, dangerous level."

Factors in malignancy

Air pollution: the damaged ozone layer allows strong ultraviolet light in and it can stimulate melanin cells and increase chances of melanoma.

Poor immunity: When the body defenses are low, cell irregularities are more common.

Race: The occurrence of melanoma is highest among Caucasians, followed by Asians and blacks.


Don't expose moles directly to sunshine, even if sunblock is used.

Don't use hormone medication without a prescription because hormones can accelerate growth of melanin cells.

Don't rub, scratch or irritate a mole.

Monitor the appearance of moles (ask a friend to help if you can't see your back) and see a doctor if there are any changes.


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