Arm naevus count linked with melanoma risk

October 17, 2015

Abstract

Introduction
Despite recent discoveries of germline and somatic mutations in melanoma, naevus count remains the most important risk factor for melanoma. Counting naevi on the whole body is time consuming. In order to identify patients at risk for melanoma, many studies have used naevus count on selected body sites as a proxy for total body naevus count.

Methods
The most predictive body site for total naevus count was assessed in a cohort of female healthy twins. This finding was replicated on a control group from UK a case-control study and a prediction model was after performed. The area under the receiver operating characteristics curve was used to evaluate the best cut off for the prediction of having more than 50 or 100 total body naevus counts.

Results
3694 female twins were included. The total body naevus count showed a steady decline after the age of 30 (p<0.001). The most predictive sites for total body naevus count were the arms and legs: the adjusted correlation coefficients were 0.50 and 0.51 (p<0.001) for right and left arm respectively and 0.49 and 0.48 for right and left arm respectively (p<0.001). The arm remained the most predictive site for total body naevus counts when replicated in a control population including both sexes. In the twin study, women with more than 11 naevi on the right arm were approximately 9 times more likely to have more than 100 naevi (OR =9.38, 95% CI: 6.71-13.11).

Conclusion
The ability to estimate total body naevus count quickly by counting naevi on one arm could be a very useful tool in assessing melanoma risk in primary care.

Source:

Ribero, S, et al. Prediction of high naevus count in a healthy UK population to estimate melanoma risk. British Journal of Dermatology. DOI: 10.1111/bjd.14216 (Open Access Article)
http://onlinelibrary.wiley.com/doi/10.1111/bjd.14216/abstract