Self-reported naevus density may lead to misclassification of melanoma risk

DEAR EDITOR, The incidence of cutaneous melanoma continues to rise, imposing a sizeable burden on health services and society.1 The strongest known risk factor for melanoma is the presence of many melanocytic naevi.2 Naevus prevalence studies use a variety of counting methods from objective counts by dermatologists/research staff to self-counts. This diversity likely contributes to the variation seen in prevalence estimates.3 Expert counts are more accurate but are labour intensive and costly. Self-counts by untrained people are attractive because they facilitate data collection from larger populations. An Australian study showed a moderately strong relationship between adults’ self-reported totalbody naevus density (none, few, some or many, based on images) and a dermatologist’s total-body naevus count.4 The authors proposed that self-reported categorical measures of naevi (naevus density) better reflect dermatologist counts than self-reported absolute counts.4 Given the importance of accurate classification, we compared the characteristics of those who correctly classified their naevus density, based on a dermatologist’s naevus count, with those who did not.