Even Normal Moles Mean Risk

Having moles on your body — even those found to be normal — can more than quadruple your risk of developing melanoma, according to a recent study presented at the 2014 World Congress on Cancers of the Skin in Edinburgh, Scotland.

The study examined medical records for two groups of UK residents: 271,656 patients diagnosed with moles in the hospital and a second group of some 10 million people with no moles. Tracking these cohorts from 1999 to 2011, researchers found the mole group 4.67 times more likely to develop melanoma both around the site of the mole and elsewhere on the body. Approximately half of all melanomas develop in preexisting moles, and previous studies have shown that the greater the number of moles someone has, the greater their odds of developing melanoma.

Moles, or nevi, are clusters of melanocytes, a type of skin cell containing the pigment that gives our skin color.  Most moles are benign, but some that appear unusual (called dysplastic nevi or atypical moles) can turn cancerous. People with atypical moles are 7 to 27 times more likely to develop melanoma than the general public.

While the study did not differentiate normal moles from atypical moles or track the number of moles in each patient, it nonetheless was noteworthy in showing that people with moles, even normal ones, have a significantly increased risk of ultimately developing melanoma, and thus should be especially vigilant. The Skin Cancer Foundation recommends performing monthly self-check skin exams head to toe, going in for annual professional skin check-ups, and practicing daily sun protection.

The biennial World Congress on Cancers of the Skin was founded by the Skin Cancer Foundation in 1983.

Published on November 3, 2014