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People at Risk for Skin Cancer Are Good at Spotting Mole Changes

WebMD Health News

May 17, 2000 -- Three-quarters of people at high-risk for a fatal form of skin cancer were able to detect increases in the size of moles on their back by doing skin self-examinations, Canadian researchers report in the May issue of the Journal of the American Academy of Dermatology.

One of the first signs that a mole is turning cancerous is an increase in size. And since early detection is the key to successfully treating skin cancer, this study's good news seems perfectly timed, as May is Skin Cancer Detection and Prevention month, according to the Atlanta-based American Cancer Society (ACS).

In the study of 103 people who had been performing skin self exams well for at least a year, 75% of people were able to notice a 4 millimeter change in the size of a mole on their mid-back, and 58% noticed a 2 millimeter change.

"The take-home message is that people with a lot of moles can be taught to do the skin self-exams and pick up on changes in the size of their moles," says lead researcher Lynn From, MD, the head of the division of dermatology at the Women's College Campus of the Sunnybrook and Women's College Health Sciences Centre in Toronto.

People with a lot of moles have about 10 times the risk of developing skin cancer compared with people who have fewer moles, she tells WebMD.

Study participants were considered to be at high risk for melanoma, a potentially fatal form of skin cancer, because they had more moles than people in the general population. Melanoma accounts for about 4% of skin cancer cases, but causes about 79% of skin cancer deaths. About 47,700 new melanomas are expected to be diagnosed in the U.S. during the year 2000, according to the ACS.

Besides growth, other signs that a mole is cancerous include an irregular border, discoloration, and an asymmetric shape -- meaning that half of the mole does not match the other half.

Study participants performed three skin self-exams in which different moles on their back were artificially enlarged with a color-matched eyebrow pencil by 0, 2, and 4 millimeters. So that participants would not know which moles were enlarged, the researchers pretended to draw on many moles.

One-quarter of people in the study could not notice an increase in mole size, and 38% said they noted a change in mole size when, in fact, there was none, From and colleagues report.

The researchers note that the mid-back is one of the most difficult areas to check for skin cancer, thus other areas on the body may yield different results. "The back is the most common spot to develop skin cancer," From tells WebMD. "We thought that if people could notice changes in their back, they could notice changes anywhere on their body."

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