Having more than 11 moles on your right arm could raise the risk of getting skin cancer in the future, research has suggested. Researchers said they have found a new way for GP’s to quickly assess whether somebody may be at risk of developing melanoma by counting moles on a “proxy” body area such as the arm or the leg, according to experts from King’s College London.
Around 20% to 40% of melanoma is thought to arise from pre-existing moles. Having more than 100 moles on the body is a “strong predictor” of developing melanoma. The study, which was funded by the Wellcome Trust, examined data from 3,594 female twins. Specially trained nurses from St Thomas’ hospital in London performed a mole count on 17 areas on each person’s body. Skin type, hair and eye colour and freckles were also recorded in the research.
The results were checked against a further study involving men and women. Scientists found that the count of moles on the right arm was most predictive of how many moles were on the entire body. Those people with more than seven moles on their right arm had nine times the risk of having over 50 on the whole body, while those with more than 11 were more likely to have more than 100.
The experts found that the area above the right elbow was particularly predictive of the total body count of moles. The legs were also strongly linked with the total count, while men’s backs also highlighted as an increased risk. The researchers concluded: “We demonstrated that arm mole count of more than 11 is associated with a significant risk of having more than 100 moles, that is in itself a strong predictor of risk for melanoma.”
Lead author Simone Ribero, of the department of twin research and genetic epidemiology at King’s, said: “The findings could have a significant impact for primary care, allowing GPs to more accurately estimate the total number of moles in a patient extremely quickly via an easily accessible body part. This would mean that more patients at risk of melanoma can be identified and monitored.”
Dr Claire Knight, health information manager at Cancer Research UK, said the finding could be useful because lots of moles makes it a higher risk for melanoma in the future. Other risk factors for melanoma include having red or fair hair, fair skin, light-coloured eyes or having been sunburnt in the past. “But less than half of melanomas develop from existing moles. So it’s important to know what’s normal for your skin and to tell your doctor about any change in the size, shape, colour or feel of a mole or a normal patch of skin. And don’t just look at your arms – melanoma can develop anywhere on the body, and is most common on the trunk in men and the legs in women.”