Co-occurrence of congenital anomalies and childhood brain tumors in 22 million live births.

Background: Children born with a congenital anomaly have a higher risk of developing a brain tumor during childhood or adolescence, but the co-occurrence between specific types of congenital anomalies and specific types of childhood brain tumors (CBTs) is not well described. This study characterized the associations between specific congenital anomalies and CBTs.

Methods: We leveraged a population-based registry linkage study of births (1990-2018), congenital anomalies, and cancer from nine states (n=22,599,099 births). Congenital anomalies were classified as major structural without a known chromosomal or genetic syndrome, chromosomal, neurofibromatosis, and/or tuberous sclerosis complex. CBT classification was based on the International Classification of Childhood Cancer for children diagnosed <20 years. Cox regression analyses were conducted separately by congenital anomaly for anomaly-CBT combinations with at least 5 co-occurring cases. We conducted analyses for any CBT and separately for astrocytoma, atypical teratoid/rhabdoid tumor, ependymoma, medulloblastoma, mixed and unspecified gliomas, and primitive neuroectodermal tumors.

Results: There were 6,247 children diagnosed with a CBT. Having any major structural anomaly was associated with risk of any CBT and across all subgroups (aHR range: 1.48-3.69) except ependymoma, particularly among children diagnosed with a tumor by 1 year of age. Of the 66 anomaly-CBT combinations analyzed, 42 were significant (p<0.05), including 25 in an earlier version of this study and 16 novel associations (aHR range: 1.46-525). Anomaly-CBT associations also differed by astrocytoma histology.

Conclusions: We observed consistent evidence that having a structural congenital anomaly increases risk of developing a CBT, particularly in infancy, which may provide insights into etiology.