Multiple primary melanomas: A common occurrence in Western Sweden

Patients diagnosed with a single primary cutaneous melanoma are at increased risk of developing multiple primary melanomas. The aim of this study is to des- cribe the epidemiology of multiple primary melanomas (invasive and in situ) in Western Sweden. Data from the Swedish Melanoma Registry from 1990 to 2013 re- vealed that 898 patients (7.4%) developed 2,037 mul- tiple primary lesions and 11,254 patients developed single lesions. The proportion of subsequent lesions that were melanoma in situ was 47%, compared with 26% of rst melanomas (p<0.0001). The median time to diagnosis of a subsequent melanoma was 38 months (95% con dence interval (CI), 53–62 months). In total, 49% of subsequent melanomas were detec- ted within 3 years. Patients and physicians should be aware of the high proportion of multiple primary mela- nomas in Western Sweden, especially during the rst years of follow-up.