The Risk of Developing Secondary Central Nervous System Tumors After Diagnostic Irradiation From Computed Tomography in Pediatrics: A Literature Review

Background: Advanced diagnostic imaging has provided tremendous benefits; however, increased use of ionizing radiation modalities such as cranial computed tomography (CT) may be associated with an increased risk of developing central nervous system tumors. Methods: A literature review identified studies published for more than the last 50 years from 1968 to 2018 that explored the association between head CT scans and developing central nervous system tumors in pediatrics. We reviewed seven studies that described and analyzed the risk of brain tumors. Results: A positive correlation between exposure to CT scans and developing central nervous system tumors was evident in all cohorts. The strength of the association varied across the studies. Exclusion of patients with predisposing factors to central nervous system tumors was examined in four studies with a decreased risk to develop central nervous system tumors noted in three studies. Two studies reported nonsignificant reduction in the excess relative risk per milliGray of brain dose after adjusting for predisposing factors, whereas the reduction was significant in one study. The frequency of CT exposure was proportional to the risk of developing tumors in two studies although not significantly maintained in two other studies. Gender had no significant effect on the central nervous system tumor risk. The calendar year at the time of imaging showed decreasing risk in those exposed to CT in more recent years compared with prior decades. Conclusions: Prospective epidemiologic studies are needed to examine the precise carcinogenic effect of exposure to ionizing radiation and help tailor further preventive measures.