Age and Cohort Trends of Malignant Melanoma in the United States

SIMPLE SUMMARY: The occurrence of melanoma in the United States is increasing over time. We examined trends in melanoma by birth year and age groups to determine if individuals born more recently experience higher rates of melanoma as they age. We examined these trends separately among men and women and by the location on the body that the melanoma occurred. Melanoma incidence has continued to increase across more recent birth years and varies by body site and sex. Melanoma incidence will likely continue to increase as younger individuals age. While these are mostly thin melanomas, treatment to prevent cancer progression is still costly, both economically and emotionally, for patients. ABSTRACT: The incidence of malignant melanoma in the United States is increasing, possibly due to changes in ultraviolet radiation (UVR) exposure due to lifestyle or increased awareness and diagnosis of melanoma. To determine if more recent birth cohorts experience higher rates of melanoma as they age, we examined age and birth cohort trends in the United States stratified by anatomic site and cancer type (in situ vs. malignant) of the melanoma diagnosed from 1975–2017. Poisson regression of cutaneous melanoma cases per population for 1975–2017 from the Surveillance, Epidemiology, and End Results (SEER) cancer registries was used to estimate age adjusted incidence for five-year birth cohorts restricted to Whites, ages 15–84. The rate of melanoma incidence across birth cohorts varies by anatomic site and sex. Melanomas at all anatomic sites continue to increase, except for head and neck melanomas in men. Much of the increase in malignant melanoma is driven by cases of thin (<1.5 mm) lesions. While increased skin exams may contribute to the increased incidence of in situ and thin melanoma observed across birth cohorts, the shifts in anatomic site of highest melanoma incidence across birth cohorts suggest changes in UVR exposure may also play a role.