People with more than 11 moles on their right arm have a higher-than-average risk of developing skin cancer, according to research published in the British Journal of Dermatology on Monday.
Researchers from King’s College London found that counting the number of moles on someone’s right arm can be used to accurately estimate how many moles the person has on their body in total.
Although only 20 to 40 percent of melanoma occur from already existing moles, doctors can use this new method to quickly identify those at risk to melanoma, which affects over 13,000 a year in the U.K.
Researchers studied data from over 3,000 female twins and said they hope the results will prove useful to doctors for identifying those at risk of skin cancer. In the study, females with more than seven moles on their right arm were nine times more likely to have 50 on their whole body, while those with more than 11 were likely to have more than 100. The study was funded by the Wellcome Trust, a global health charity based in London.
Lead author, Simone Ribero of the Department of Twin Research & Genetic Epidemiology, 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.”
According to Cancer Research U.K., other risk factors for melanoma include having red or fair hair, fair skin, light-colored eyes or having been sunburnt in the past.
Dr Claire Knight, health information manager at Cancer Research U.K., praised the research but warned that “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, color 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.”