4 or more CT scans in kids increases risk for cancers: Study

For children under age 18 years, a single computed tomography (CT) scan is not associated with an increased risk of brain tumours, leukemia or lymphoma, but exposure to 4 or more scans before adulthood more than doubles the risk, according to new research in CMAJ (Canadian Medical Association Journal).

Computed tomography in children has increased worldwide in recent decades, but there is conflicting evidence about the risks of cancer from these scans in this cohort. Computed tomography scans use low-dose radiation that can damage cells.

To understand if there is a link between CT scans and certain types of cancer and tumours, researchers looked at data on 7807 children in Taiwan diagnosed with intracranial tumours, leukemia or lymphoma between 2000 and 2013 matched with 78 057 controls within the Taiwanese national health system. They compared tumour rates for those who had had CT scans versus those who had not.

They found that for 1 CT scan, there was no increased risk of any of the cancers compared with no exposure. Children who received 2 to 3 CT scans had an increased risk of intracranial tumours; those who received 4 or more CT scans had a more than twofold risk of intracranial tumours, leukemia and non-Hodgkin lymphoma.

Reference:

Risks of leukemia, intracranial tumours and lymphomas in childhood and early adulthood after pediatric radiation exposure from computed tomography,Canadian Medical Association Journal, DOI: 10.1503/cmaj.221303