Perinatal And Early Life Risk Factors For Childhood And Adolescent Melanoma

Katherine WOJCIK, University of Souther California, United States

1 Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
2 Spatial Sciences Institute, Dornsife College of Arts, Letters, and Sciences, University of Southern California, Los Angeles, California, USA
3 Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, California, USA

Purpose: Melanoma, the deadliest form of skin cancer, is the 2nd most common cancer diagnosed under 30 years of age in the US, where more than 75,000 new melanomas occur annually. Nearly 9,000 will occur in California. Known risk factors for melanoma have been assessed from studies in adults over 50 years, so current knowledge may not reflect important contributors to pediatric, adolescent, and young adult melanoma, which represents early onset disease likely to have distinct age-specific risk factors or windows of susceptibility that differ from older adults. Striking gender differences by age exist, where younger females are at much greater risk of melanoma than men, and in older adulthood the opposite is true.
Methods: We conducted a population-based, case-control study of Californians (1,396 melanoma cases and 27,920 controls, obtained by linking cancer registry data to birth records) to investigate the association of melanoma and early life risk factors, including early life ambient ultraviolet radiation(UV) and infant birthweight, along with interactions by age and race/ethnicity.
Results: Higher UV exposure was significantly associated with 26-43% higher odds of melanoma depending on age at diagnosis, but particularly for ages 15-19yrs. High birthweight versus normal birthweight was associated with 20% increased odds(OR:1.20;95%CI:1.03-1.41), while low birthweight appeared protective(OR:0.58;95%CI:0.42-0.80) after adjustment. Among Hispanic persons, odds of melanoma at ages 0-5 were 3 times the odds of melanoma at ages 25-29 (OR:3.05;95%CI:1.50-6.17).
Conclusions: Higher birthweight and UV in early life are important melanoma risk factors for early onset disease. Early UV exposure may play a particularly strong role in melanomas at ages 15-19, while persons of Hispanic background may be more likely to get a melanoma in early childhood than as a young adult. 
Funding: This work was supported by the NIEHS R21ES018960, R21ES019986, P30ES007048, by the NCI and the NICHD under grant R01CA158407.