A recent study analyzed melanoma incidence trends across high-, moderate-, and low-ambient sun exposure regions, uncovering significant gender- and site-specific differences. Researchers evaluated data spanning 1982 to 2018 from Queensland, Australia; U.S. Whites; and Scotland using age–period–cohort models to identify patterns influenced by environmental and biological factors.
Among men, melanoma incidence was highest on the trunk across all populations, with age-standardized rates in 2018 reaching 35.86/100,000 in Queensland, 14.67/100,000 in US Whites, and 8.45/100,000 in Scotland. For women, lower limb melanomas historically dominated, with 2018 rates of 12.33/100,000 in Queensland and 4.27/100,000 in US Whites. Notably, truncal melanoma rates among women have been rising in recent cohorts.
“These sex-specific trends reflect heterogeneous patterns of incidence across anatomic sites that vary consistently with age,” the researchers noted in The Journal of Investigative Dermatology. Male predominance in truncal and head/neck melanomas emerged by ages 25 and 40, respectively, while female predominance in lower limb melanoma persisted through middle age.
The study revealed turning points in melanoma incidence among younger birth cohorts, particularly in Queensland, where rates have declined. These findings suggest improved public health measures may be mitigating melanoma risk.
Environmental factors, such as shifting UV exposure patterns due to behavioral or clothing trends, likely influence these trends. Additionally, innate biological differences—including sex-specific hormonal and genetic factors—may play a role. “Changing exposure to UVR is implicated, possibly superimposed upon innate differences between the sexes in site-specific susceptibility,” the authors wrote.
According to the study, understanding site-specific risk factors could help inform interventions to reduce melanoma incidence globally. Understanding site-specific risk factors—from sun protection behaviors to genetic predispositions—could inform interventions to reduce melanoma incidence globally.
Acknowledged limitations include potential regional data collection inconsistencies and the ecologic nature of the analysis. Despite this, the findings—derived from robust population-based registries—offer critical insights into the interplay of environmental and biological factors shaping melanoma risk.