Pediatric Brain Tumor Risk Increases With CT Radiation Exposure

Head and neck computed tomography (CT) imaging increases the risk for pediatric brain tumors, according to the findings of a study published in the International Journal of Cancer.

Children are more vulnerable to the health effects of ionizing radiation than adults.

To evaluate whether the radiation from head and neck CT may increase the risk for brain tumors, researchers from Tampere University in Finland sourced data for this study from the Finnish Cancer Registry (FCR), the Population Information System, and 10 hospital databases. Patients (n=1067; boys, 53.9%; aged 0-4 years, 36.5%) aged 0 to 15 years diagnosed with brain tumor between 1990 and 2016 were matched with 3 healthy control individuals (n=3200; boys, 53.9%; aged 0-4 years, 36.5%). Exposure to radiation via head and neck CT imaging through 2011 and estimated radiation exposure were related with brain tumor risk.

Among individuals diagnosed with brain tumor and healthy individuals, 3.1% and 3.0% were large for gestational age, 8.8% and 0.2% had cancer predisposition syndromes (P <.001), and 12.1% and 10.7% were exposed to cigarette smoking during gestation, respectively.

A total of 9 cases (0.9%) and 10 controls (0.4%) underwent head and neck CT. The average estimated absorbed brain radiation dose was 16.7 (range, 3.5-41.8) mGy per CT scan, in which the cumulative absorbed brain radiation dose was higher among cases than control individuals (mean, 3.5 vs 7.9 mGy), respectively.

Head and neck CT associated with risk for brain tumor (odds ratio [OR], 5.15; 95% CI, 2.27-11.68) and brain glioma (OR, 3.25; 95% CI, 1.08-9.75), with excess OR of 7.80 (95% CI, 2.45-13.42) and 4.57 (95% CI, -1.16 to 10.63) per 100 mGy of cumulative brain radiation doses, respectively. The relationship between CT imaging and brain tumor risk remained significant after adjusting for maternal socioeconomic status (adjusted OR, 2.69; 95% CI, 1.06-6.85).

After excluding individuals with cancer predisposition syndromes, risk for brain tumor was associated with CT imaging (OR, 2.84; 95% CI, 1.12-7.19). No age (P =.97) or gender (P =.91) effects were observed. The excess OR was 5.50 (95% CI, 0.31-10.95) per 100 mGy of cumulative brain radiation dose.

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No significant relationship between head and neck CT and malignant brain tumor risk was observed.

Stratified by brain radiation dose tertiles, risk for brain tumor was only associated with the highest tertile relative to no radiation exposure (OR, 6.00; 95% CI, 1.10-32.76).

This study was limited by not having access to data about CT indication and the small sample size.

“[W]e reported a positive association between a history of head/neck CT imaging and the risk of brain tumors in childhood. Our findings contribute to the body of evidence on the risks of low dose ionizing radiation in pediatric populations,” the researchers concluded.