title: Confounding of the association between radiation exposure from CT scans and risk of leukemia and brain tumors by cancer susceptibility syndromes.
abstract: Recent studies linking radiation exposure from pediatric computed tomography (CT) to increased risks of leukemia and brain tumors lacked data to control for cancer susceptibility syndromes (CSS). These syndromes might be confounders because they are associated with an increased cancer risk and may increase the likelihood of pediatric CT scans. We identify CSS predisposing to leukemia and brain tumors through a systematic literature search and summarize prevalence and risk. Since empirical evidence is lacking in published literature on patterns of CT use for most types of CSS, we estimate confounding bias of relative risks (RR) for categories of radiation exposure based on expert opinion about patterns of CT scans among CSS patients. We estimate that radiation-related RRs for leukemia are not meaningfully confounded by Down syndrome, Noonan syndrome and other CSS. Moreover, tuberous sclerosis complex, von Hippel-Lindau disease, neurofibromatosis type 1 and other CSS do not meaningfully confound RRs for brain tumors. Empirical data on the use of CT scans among CSS patients is urgently needed. Our assessment indicates that associations with radiation exposure from pediatric CT scans and leukemia or brain tumors reported in previous studies are unlikely to be substantially confounded by unmeasured CSS.
authors.affiliation: Department of Epidemiology and Biostatistics, Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Johanna M
authors.initials: JM
authors.lastname: Meulepas
authors.forename: Cécile M
authors.initials: CM
authors.lastname: Ronckers
authors.forename: Johannes
authors.initials: J
authors.lastname: Merks
authors.forename: Michel E
authors.initials: ME
authors.lastname: Weijerman
authors.forename: Jay H
authors.initials: JH
authors.lastname: Lubin
authors.forename: Michael
authors.initials: M
authors.lastname: Hauptmann
mesh_terms: D001932:Brain Neoplasms / Q000453:epidemiology*; D002648:Child; D015897:Comorbidity; D015986:Confounding Factors, Epidemiologic; D003952:Diagnostic Imaging; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007938:Leukemia / Q000453:epidemiology*; D008017:Life Expectancy; D008297:Male; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D009386:Neoplastic Syndromes, Hereditary / Q000453:epidemiology; D015995:Prevalence; D000069079:Radiation Exposure; D018570:Risk Assessment; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000009:adverse effects*