Confounding of the Association between Radiation Exposure from CT Scans and Risk of Leukemia and Brain Tumors by Cancer Susceptibility Syndromes

Abstract

Background: 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 CT scans performed in children.Methods: We identify CSS predisposing to leukemia and brain tumors through a systematic literature search and summarize prevalence and risk estimates. Because there is virtually no empirical evidence 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 the current and previous patterns of CT scans among CSS patients.

Second follow-up of a German cohort on childhood cancer incidence after exposure to postnatal diagnostic x-ray

“…Any patients with an indication of cancer as the reason for the examination were excluded from the cohort. Nevertheless, we cannot completely rule out that certain cancer susceptibility syndromes like the Li-Fraumeni syndrome for leukemia and brain tumors or the Noonan syndrome for leukemia [30] caused an increased risk for childhood cancer or lead to additional CT scans that would confound our results. However, we did not observe an increased risk for leukemia or CNS tumors in our study.…”

Both sides now: diagnostic imaging medical physics in two hemispheres

“…The findings of 50-60 mGy tripling leukaemia and brain cancer risk, and 4.5 mSv resulting in a 24% increase in cancer and leukaemia incidence brings known deleterious effects into diagnostic imaging territory. Subsequent studies have refined but not contradicted these conclusions [6,7]. Similar conclusions emerge from the INWORKS study on occupationally exposed workers [8].…”

Confounding of the association between radiation exposure from CT scans and risk of leukemia and brain tumors by cancer susceptibility syndromes

“…Nevertheless, the results of our analyses provide guidance in situations which might be encountered in other epidemiological studies of diagnostic imaging and cancer risk. This article contains information which was published previously [19] and retracted [20] due to an inadvertent error in calculations for two CSS.…”