Counting the number of moles found on an arm could be a “very useful tool” for primary care clinicians to determine the number of moles on the entire body and therefore risk of skin cancer.
Skin cancer risk is thought to increase by 2-4% per additional mole on the body, but counting the total number on the entire body can be time consuming in a primary care setting, noted researchers at King’s College London.
Their study sought to identify whether part of the body could be used as an accurate “proxy” site for a full body count.
“The findings could have a significant impact for primary care”
They also assessed the “cut off” number of moles that can be used to predict those at the highest risk of developing skin cancer.
The researchers looked at data on 3,594 female Caucasian twins between January 1995 and December 2003 as part of the TwinsUK study.
Twins underwent a mole count on 17 body sites performed by trained nurses. This was then replicated in a wider sample of participants from a previously published UK melanoma study.
The researchers found that the count of moles on the right arm was most predictive of the total number on the whole body.
Those with more than 11 on their right arm were more likely to have over 100 on their body in total, meaning they were at a higher risk of developing a melanoma.
The findings could help clinicians to more easily identify those at the highest risk of developing a melanoma, suggested the study authors in the British Journal of Dermatology.
They also found that the area above the right elbow was particularly predictive of the total body count of moles. The legs were also strongly associated with the total count as well as the back area in males.
Lead author Simone Ribero 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,” he said.
He added: “This study follows on from previous work to identify the best proxy site for measuring the number of moles on the body as a whole.
“The difference here is that it has been done on a much larger scale in a healthy Caucasian population without any selection bias and subsequently replicated in a case control study from a similar healthy UK population, making the results more useful and relevant.”