Pediatric Melanoma: Geographic Trends in Incidence, Stage, and Mortality in the United States

Abstract

IntroductionPediatric melanoma is the most commonly diagnosed skin cancer in children, with the annual incidence recently increasing by an average of 2% each year. Ultraviolet (UV) radiation from excessive sun exposure is an important carcinogenic risk factor, with penetration varying greatly throughout the country. Consequently, an individual's geographic location may play a role in how much exposure to high UV index rays they receive throughout their lifetime. The objective of this study was to use the surveillance, epidemiology, and end results SEER database to study geographic trends in incidence, staging, and mortality of pediatric melanoma between 2009 and 2019 and determine their relation to UV index in the United States. Materials and methodsA retrospective analysis of pediatric patients from 0 to 19 years in the surveillance, epidemiology, and end results 22 registries incidence database (17 states) and 17 registries incidence-based mortality database (12 states) was conducted from 2009 to 2019 based on a diagnosis of melanoma of the skin using the International Classification of Childhood Cancer codes for malignant melanoma. Data regarding patient demographics and incidence, staging, and mortality per state were extracted. Incidence data were geographically mapped and mean UV index distribution from www.epa.gov was superimposed. ResultsIncidence of pediatric melanoma was stratified regionally, with a total of 1665 new cases from 2009 to 2019. The Northeast had 393 new cases, with 244 (62.1%) localized cases, 55 (14.0%) lymph node-invasive and metastatic (advanced) cases, and 6/146 (4.1%) cases of mortality. The Midwest had 209 new cases, with 123 (58.9%) localized cases, 29 (13.9%) advanced cases, and 1/57 (1.8%) case of mortality. The South had 487 new cases, with 224 (46.0%) localized cases, 104 (21.4%) advanced cases, and 8/232 (3.4%) cases of mortality. The West had 576 new cases, with 364 (63.2%) localized cases, 82 (14.2%) advanced cases, and 23/551 (4.2%) cases of mortality. Mean UV index was 4.4 in the Northeast, 4.8 in the Midwest, 7.3 in the South, and 5.5 in the West from 2006 to 2020. The regional difference in incidence was not statistically significant. There was a statistically significant increased number of advanced cases in the South as compared to the Northeast (P = 0.005), West (P = 0.002), and Midwest (P = 0.02), with a significant correlation coefficient of 0.7204 between advanced cases and mean UV index in the South. ConclusionsThere is a statistically significant increased incidence of lymph node-invasive and metastatic pediatric melanoma cases in the South as compared to the West, Northeast, and Midwest regions of the United States. There is also a significant correlation between the incidence of lymph node-invasive and metastatic pediatric melanoma cases and UV index. In the pediatric population, there is no statistically significant association between total incidence and mortality of melanoma and geographic region. There is an increased prevalence of pediatric melanoma seen in White and female patients. This suggests that an individual's geographic location in the United States during childhood may play a role in their likelihood of malignant melanoma development, advanced-stage melanoma development, and mortality.