EPID-07. MAJOR CONGENITAL ANOMALIES AND RISK OF CHILDHOOD BRAIN TUMORS IN 9 STATES

Abstract Children with congenital anomalies have a higher risk of developing a childhood brain tumor (CBT), but it remains unclear if associations vary by cancer histology, which could inform our understanding of these associations. Thus, we characterized co-occurrences of major congenital anomalies with six CBTs. We leveraged a population-based registry linkage study of live births, congenital anomalies, and cancer from nine states. Dates of birth and last follow-up varied by state, ranging between January 1, 1990 to December 31, 2018, for a total of 22,599,099 live births. CBT classification was based on the International Classification of Childhood Cancer for children diagnosed up to age 18 years. Major congenital anomalies were classified based on the National Birth Defects Prevention Network Surveillance Guidelines. Children with any genetic anomalies were excluded. We used Cox regression to evaluate associations between major congenital anomalies and astrocytoma, medulloblastoma, ependymoma, atypical teratoid/rhabdoid tumor (ATRT), primitive neuroectodermal tumors (PNET), and mixed and unspecified gliomas (“mixed gliomas”), adjusting for sex, state, maternal education, maternal race/ethnicity, and maternal age. Sensitivity analyses were conducted stratifying by number of major anomalies (0, 1, 2+) and age at cancer diagnosis (<1, 1-4, 5-9, 10+ years). There were 5,685 diagnosed with any CBT. Having any major congenital anomaly was significantly associated with astrocytoma, ATRT, medulloblastoma, mixed glioma, and PNET (aHR range: 1.79-5.78) but not ependymoma. When stratified by number of major anomalies, effect estimates were similar. Due to small numbers when stratified by age at cancer diagnosis, unadjusted analyses were conducted. Associations were strongest in children diagnosed with astrocytoma, ATRT, medulloblastoma, mixed glioma, or PNET before age 1 (HR range: 3.03-5.47) compared to other age groups (HR range: 1.25-3.07). Children with any major congenital anomaly have an increased risk of developing astrocytoma, ATRT, medulloblastoma, mixed glioma, or PNET, particularly by 1 year.