No Overall Association Between Prenatal X-ray Exposure and Childhood Brain Tumor
Overall, children born to women who received an X-ray during pregnancy are not more likely than other children to develop a brain tumor; there was a suggestion, however, that risk of a certain type of brain tumor-primitive neuroectodermal tumors-may be increased. These results were published in the British Journal of Cancer.
An abnormal growth of cells in the brain is called a brain tumor. Brain tumors may be malignant (cancerous) or benign (non-cancerous).
Other than leukemia and lymphoma, brain tumors are the most common type of cancer in children. Factors that increase the risk of childhood brain tumors include radiation therapy to the brain and certain rare genetic disorders, but few other risk factors have been established.
To explore the relationship between prenatal X-ray exposure and risk of childhood brain tumors, researchers conducted a study in Sweden. The study included 512 children who had been diagnosed with a brain tumor before the age of 15 years and 524 children who had not been diagnosed with a brain tumor. Information about maternal X-ray exposure during pregnancy was collected from medical records.
- Overall, the frequency of prenatal X-ray exposure was similar among children with and without brain tumors. The mothers of 10.7% of children with a brain tumor and 9.4% of children without a brain tumor had received an abdominal X-ray during pregnancy. Most of these exposures occurred during the third trimester of pregnancy.
- When specific types of brain tumors were analyzed separately, there was a suggestion that primitive neuroectodermal tumors (PNET) may be more frequent in children with prenatal X-ray exposure than in children without prenatal X-ray exposure. This finding did not meet the criteria for statistical significance, however, suggesting that it could have occurred by chance alone. The relatively small number of children with PNET could have contributed to this lack of statistical significance.
The researchers conclude that overall, prenatal X-ray exposure does not appear to significantly increase the risk of childhood brain tumors. Looking at specific types of childhood brain tumors, there was a suggestion of a link between prenatal X-ray exposure and PNET, but larger studies would be necessary to draw firm conclusions.
Reference: Stålberg K, Haglund B, Axelsson O, Cnattingius S, Pfeifer S, Kieler H. Prenatal X-ray exposure and childhood brain tumours: a population-based case-control study on tumour subtypes. British Journal of Cancer. 2007;97:1583-1987.