Accuracy of Self-Report of Nevus and Pigmentation Phenotype Compared to Clinical Assessment in Young Australian Adults

There is no formal community-wide melanoma screening program in Australia, but the importance of early detection and regular skin self-examination is generally well understood. It is important that individuals are able to identify key melanoma risk factors so that those at high risk can modify their sun-related behaviours and take appropriate preventative actions from a young age. Aims: 1) To evaluate the accuracy of self-reported pigmentation and nevus phenotype compared to clinical assessment, and 2) to examine agreement between clinically-measured whole-body nevus count and clinically-measured nevus count on selected anatomical regions, given that localised mole count is often used as a proxy measure. Methods: The sample included 456 cases with invasive cutaneous melanoma diagnosed between ages 18–39 years and 538 controls from the population-based Australian Melanoma Family Study. Participants completed a questionnaire regarding their pigmentation and nevus phenotype, and attended a clinical skin examination with a dermatologic trainee. Results: There was strong agreement between self-reported and clinical measurement for eye color (weighted kappa, Kw, = 0.83, 95% confidence interval (CI) 0.80–0.86); and moderate agreement for hair color (Kw = 0.52, 95% CI 0.47–0.56) There was poor agreement for skin color when using spectrophotometer-derived individual typography angle (ITA) scores as the objective measure (Kw = 0.18, 95% CI 0.14–0.22). Participants underestimated their nevus counts. The Spearman correlation was 0.43 (95% CI 0.38–0.49) when comparing clinically-measured total body nevus count (≥2 mm) with self-reported nevus density categories, and the intraclass correlation was 0.36 (95% CI 0.30–0.41) when comparing nevus counts on the back. There was good agreement between quartile distributions of clinically-measured site-specific nevus counts with total body nevus counts, particularly for the arms (Kw = 0.76 for men and 0.80 for women). Conclusions: Agreement between self-reported pigmentation and nevus phenotype compared to clinical assessment ranges from poor to excellent, depending on the measure. For studies where a full body nevus count is impractical, measuring nevus counts on the arms would be an acceptable alternative.