Disparities in Melanoma Incidence Between Sex and Age Populations in the United States Between 2001 and 2021

Introduction: This population-based study aimed to determine the incidence rates of melanoma in the U.S. and specifically assess the sex- and age-specific differences among different populations. Previous studies showed an increase in incidence of melanoma, but no clear sex-specific rates.

Methods: The United States Cancer Statistics (USCS) database, which covers 98% of the U.S. population, was used to identify patients with melanoma between 2001-2021. Melanoma incidence rates per 100,000 population were age-adjusted and calculated using SERR*Stat software and were stratified by sex and age into older and younger patients (age cutoff of 40 years). Time-trends (reported as annual percentage change “APC” and average APC “AAPC”) were estimated using Joinpoint regression via the modified weighted Bayesian Information Criteria method. Sex-specific trends were compared using the tests of parallelism and identicalness (P<0.05).

Results: Overall, there were 1,480,740 patients diagnosed with melanoma in the U.S. between 2001-2021. Melanoma incidence rates increased in men (AAPC=1.15; P<0.01) and women (AAPC=1.30; P<0.01). In older patients, incidence rates increased in men (AAPC=1.47; P<0.01) and women (AAPC=1.86; P<0.01) without significance (P=0.35).

However, in younger patients (149,020 patients), melanoma incidence decreased in younger men (AAPC= -2.19%; P<0.01), but not in younger women (AAPC= - 0.54%; P<0.19). Sex-specific difference was significant with absolute AAPC value of 1.65 (P<0.01) and non-parallel non-identical trends (P-values<0.01).

Discussion: In summary, there was a decline in melanoma cases among men but no change among women with significant differences. This sparks the need for additional research to delve into the potential causes of these sex-based differences in cases of melanoma.