Maternal exposure to medical radiation and Wilms tumor in the offspring: a report from the Children's Oncology Group

This study examined the association between pre-conception and in utero maternal medical radiation exposure and Wilms tumor, using data from a large population-based case-control study. Cases were identified from the National Wilms Tumor Study Group. Controls were identified by random digit dialing and frequency matched to child's age and geographic area of residence in the United States and Canada. Interview data from 512 cases and 509 controls were analyzed using multivariable logistic regression. Odds ratios (OR) and 95% confidence intervals (CI) for Wilms tumor and exposure to: (1) maternal X-ray alone and; (2) all medical radiation types (X-ray, CT, RT, Nuclear scans, Fluoroscopy) combined, for the period from two years before conception until child birth were estimated after adjustment for age, geographic area, maternal education, and household income. We found no consistent association between the risk of Wilms tumor and either maternal X-ray exposure (OR 0.9, 95% CI 0.7-1.3) or all medical radiation types combined (OR 0.9, 95% CI 0.7-1.2). No meaningful associations were seen for analysis of gonadal or non-gonadal radiation exposure. Our study did not find any consistent pattern of association between Wilms tumor and maternal radiation exposure during pre-pregnancy or pregnancy period. In view of the negative findings from the largest case control study of this question to date, the reduced doses of biological radiation during pregnancy, and the requirements for an improved study design, we believe that future studies of this exposure may not be a priority for research on Wilms tumor.