Number of moles on right arm could indicate melanoma risk

Having 11 or more moles on the right arm was found to show an increased risk for cancer in a new study.

By Stephen Feller

LONDON, Oct. 19 (UPI) -- Mole counts are one of the basic ways that doctors assess risk for melanoma. Researchers at the University College London devised a method of estimating the number of moles on a person's body, using it to estimate their risk for skin cancer.

Most moles do not turn into cancer, however the researchers found in a new study that women with more than 11 moles on their right arm were more likely to develop a melanoma.


The method of determining risk is based on the total number of moles on a person's body, but counting moles on the entire body can be time consuming in a regular patient visit. Researchers said assessing patients with an estimate at first could save time and indicate earlier if patients are at risk.

"The findings could have a significant impact for primary care, allowing general practitioners to more accurately estimate the total number of moles in a patient extremely quickly via an easily accessible body part," Simone Ribero, a researcher in the department of twin research and genetic epidemiology at University College London, said in a press release. "This would mean that more patients at risk of melanoma can be identified and monitored."


The researchers worked with 3,694 female twins between January 1995 and December 2003. Each of the twins had a skin examination with moles counted on 17 sites on their bodies by trained nurses. The same counting method was used in an additional group of about 400 men and women.

They found arms and legs were the most representative of the total number of moles on the body, settling on the right arm as the most accurate. Women with more than seven moles on their right arm were nine times at risk of having more than 50 on their entire body. Women with 11 on their arm were more likely to have over 100 moles on their bodies, which the researchers determined as a cut-off for indicating a higher risk of cancer.

Ribero said the results of the study could help primary care physicians better evaluate risk for and diagnose melanoma.

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The study is published in the British Journal of Dermatology.

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