Brain tumor risk after exposure to medical ionizing radiation

Abstract

OPS 26: Radiation, EMF, cancer and mortality, Room 114, Floor 1, August 26, 2019, 4:30 PM - 5:45 PM Background/Aim: We explored the association of cumulative ionizing radiation (IR) exposure from medical procedures during prenatal and postnatal life with brain cancer risk in the MOBI-kids study. Methods: MOBI-kids is an international (Australia, Austria, Canada, France, Germany, Greece, India, Israel, Italy, Japan, Korea, New-Zealand, Spain, The-Netherlands) case-control study of 899 brain tumour cases and 1910 controls, 10 to 25 years. Medical radiological history was collected through a personal interview, including exposure of the mother during pregnancy. In radiation epidemiology, the exposure measure is the absorbed dose to the target organ. Through a literature review, we collected values of the brain absorbed dose during each examination by age and time-period. We calculated the cumulative IR dose to the brain for each subject by summing over the dose assigned to each procedure. Conditional logistic regression models were used for risk estimation with a lag-period of two years to exclude procedures due to the current cancer. Presence of neurological, mental and genetic condition was taken into account as confounders. Analyses were conducted on 645 neuroepithelial cases and 1700 matched controls (sex, age, country). Results: Overall, the doses were very low (median 0.02 mGy). We did not observe an increase of risk for postnatal exposure of 5-30 mGy, 30-50 mGy, and 50-100 mGy categories (totally 44, 117, 37 subjects respectively) when compared to the 2110 subjects in the 0-5 mGy category. The Odds Ratio for a postnatal exposure above 100 mGy was 1.63 (CI: 0.44; 6.00; 11 subjects) and for a prenatal exposure above 5 mGy was 1.55 (CI: 0.57, 4.23; 20 subjects). Conclusions: The majority of participants were exposed to very low dose, thus the statistical power was low. We found little evidence of an association between prenatal and postnatal exposure to medical IR and neuroepithelial brain cancer risk in children and adolescents.