Mole count 'may indicate skin cancer risk'
22 October 2015 07:58
A dermatologist examines a mole on a patient's arm
Someone who has more than 11 moles on their right arm has an increased risk of skin cancer, a study suggests.
Researchers from King's College London say counting moles on the right arm is a quick way for GPs to identify those most likely to develop melanoma.
About 20% to 40% of melanoma cases are thought to arise from pre-existing moles.
The scientists found that counting moles in a "proxy" body area such as the arm was a good indicator of total moles on the body. Having more than 100 is a "strong predictor" of skin cancer.
People who have lots of moles need to take extra care in the sun.
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The mole study, published in the British Journal of Dermatology, examined data from almost 3,600 female twins.
Specially trained nurses from St Thomas' Hospital in London counted moles on 17 areas of each person's body. Skin type, freckles, hair and eye colour were also recorded.
The results were then checked against a further study involving both men and women.
The research showed that the mole count on the right arm was most accurate in predicting how many moles were on the whole body.
Those with more than seven moles on their right arm were nine times more likely to have over 50 moles on their body.
Those with more than 11 on their right arm had a greater chance of having at least 100 moles on their body.
Legs and backs also linked
The research, funded by the Wellcome Trust, found that the area above the right elbow was particularly predictive of the total count of moles.
Legs were also strongly linked with the total body count, as were men's backs.
The report's lead author, Simone Ribero, from the department of twin research and genetic epidemiology, says the research could be a useful tool for GPs.
The expert believes the findings could have a significant impact for primary care, allowing GPs to more accurately estimate the total number of moles in a patient quickly.