Risk factors associated with first and secondary primary melanomas in a high-incidence population

An increasing number of people develop more than one primary melanoma. The prospective QSkin cohort study in Australia compared clinical characteristics of first and second primary melanomas and studied risk factors for developing first and second primary melanomas. Having many moles at age 21 years was more strongly associated with second than first primary melanoma, as was high genetic melanoma predisposition (ie, polygenic risk score in tertile 3). Second melanomas were more strongly associated with a history of multiple skin cancer excisions than first melanomas.