8574 Background: Invasive melanoma is the second most common cancer in young adults, yet they exhibit poor skin-protective behavior. We previously demonstrated a significant association between melanoma risk, melanocortin receptor (MC1R) polymorphisms, and indoor ultraviolet light (UV) exposure. As existing melanoma risk models do not take these factors into account, we investigated whether these variables would improve the predictive ability of a clinical risk model, especially in a younger population. Methods: We determined MC1R genotype and collected self-reported phenotypic and UV (indoor and outdoor) exposure variables from 923 melanoma cases and 813 healthy controls between ages 25 – 59 from the Minnesota Skin Health Study. These data were initially used to develop a clinical melanoma risk model (Model A) with conventional risk factors (i.e. age; gender; hair, skin, and eye color; mole count, freckling, and family melanoma history). We then developed a second model (Model B) combining outdoor UV, indoor UV, and MC1R genotype variables with those in Model A to determine if the model’s predictive ability improved. Finally, we assessed the predictive ability of both models when confined to younger subjects (ages 25-35). Results: The clinical model, combining conventional melanoma risk factors (Model A), yielded an area under the receiver operating characteristic curve (AUC) of 0.72 (95% CI 0.70 – 0.75). Incorporating outdoor UV, indoor UV, and MC1R genotype variables (Model B) increased the AUC to 0.75 (p=0.001, 0.72 – 0.77). Confining the analyses to younger subjects substantially increased the AUC of Model A to 0.78 (0.72 – 0.84) and Model B to 0.83 (p=0.007, 0.78-0.88). Conclusions: This preliminary risk model is the first in melanoma to demonstrate that the addition of genotypic data and indoor UV exposure results in a measurable increase in predictive ability when compared to models comprised only of clinical and outdoor UV exposure variables. The enhanced predictive ability of the model (AUC>0.80) when limited to younger individuals suggests the potential for developing tools to facilitate targeted screening and prevention strategies in melanoma.
High Birth Weight, Early UV Exposure, and Melanoma Risk in Children, Adolescents, and Young Adults
