Familial risks and incidence rates for childhood nervous system tumors in Sweden

Abstract

Background: Childhood (< 20 years) nervous system tumors manifest in some rare cancer syndromes but how commonly they present with familial clustering between various histological types is not well known at a nation-wide level. Our aim is to enhance understanding of familial risks in childhood nervous system cancers. Methods: We used the Swedish population and cancer data from years 1958-2021 to address familial risks among nervous system cancers when the case was diagnosed before age 20 years but the proband could be diagnosed at any age. Adjusted familial (relative) risks were expressed as standardized incidence ratios (SIRs). Results: Familial childhood cancer cases amounted to 123 in the brain, 15 in the spinal cord and 9 in peripheral nerves. Familial risk for concordant brain cancer was about 2.0 irrespective of proband. Concordant risk of spinal cord cancer was high when mothers (17.92) or siblings were probands (24.91). High familial risk of 34.53 was recorded for hemangioblastoma, and moderate high risks were observed also for schwannoma (4.07), ependymoblastoma (3.48) and female ganglioneuroma (7.72) whereas astrocytoma risks were at the level of common cancers at other sites (1.7-2.0). Hemangioblastoma families appeared not to be related to von Hippel-Lindau syndrome because of lack of pathognomonic signs other than hemangioblastoma in the families. Conclusion: In spite of the low number of childhood nervous system tumors, we observed high familial risks for, probably novel, syndromic hemangioblastoma, and schwannomas for which concordant clusters were found particularly in the spinal cord. Inquiring about a detailed family history at diagnosis of a nervous system cancer in childhood may reveal a syndromic disease due to a constitutional variant amenable to treatment.