Birth characteristics and risk of Ewing Sarcoma

Purpose: The incidence of Ewing sarcoma varies according to race and ethnicity, and genetic susceptibility is known to affect disease risk. Apart from these factors, the etiology of Ewing sarcoma is largely undescribed. Methods: : We compared a population-based series of 556 Ewing sarcoma cases diagnosed in California in 1988-2015 with 50 controls per case frequency matched on the year of birth. Results: : Compared to non-Latino Whites, Blacks (odds ratio [OR] = 0.07, 95% confidence interval [CI]:0.03-0.18), Asians (OR = 0.57, 95%CI: 0.41-0.80), and Latinos (OR = 0.73, 95% CI: 0.62-0.88) have a significantly lower risk of Ewing sarcoma. In a multivariable analysis controlling for race/ethnicity and other birth characteristics (e.g., gestational age, mode of delivery, birth order, maternal age), birthweight was also identified as a significant risk factor (OR = 1.09, 95%CI: 1.00-1.18 for each 500 g increase in birthweight). A separate family-based cancer clustering analysis did not suggest any strong role for familial predisposition alleles, despite evidence for such a role in other childhood sarcomas (rhabdomyosarcoma and osteosarcoma). Conclusions: : In sum, this population-based study with minimal selection and no recruitment bias provides support for a role of accelerated fetal growth in the etiology of Ewing sarcoma in addition to more precise estimates of racial/ethnic variation in disease risk. This comparatively large analysis of birth characteristics and Ewing sarcoma in a multiethnic population should stimulate further investigations into genetic and environmental causes.