A large Dutch study now sheds new light on this issue. Researchers led by Michael Hauptmann of the Netherlands Cancer Institute analyzed the data of 168,394 children who received one or more CT scans in 42 Dutch hospitals between 1979 and 2014. During the 10 years following their scan(s) these children indeed were more likely to develop a brain tumor than other children. Moreover, the more CT scans a child undergoes, the higher the risk: the radiation from five scans roughly doubles the risk. No association was found for leukemia. The researchers publish their results in the Journal of the National Cancer Institute (JNCI) on July 18th.
Hauptmann: "We estimate that roughly 1 extra brain tumor is caused by the radiation from the approximately 10,000 annual head scans among Dutch children. Every year, about 120 brain tumors are diagnosed in Dutch children. Despite the radiation risk, most children benefit incredibly from the scans. For example, if a child has a headache after an accident it is important not to miss a brain hemorrhage."
The researchers interpreted their findings carefully, mainly because clinicians use CT scans precisely for detecting brain tumors. This means that in children undergoing head CT's, tumors are found more often than in the general population. Hauptmann: "We took this into account by excluding tumors diagnosed within five years after the first scan."
Outside the Netherlands and in regional hospitals within the Netherlands, reducing the number of CT scans in children is likely to yield the most benefit, Hauptmann thinks. "In the Netherlands, doctors are already quite conservative in scanning children, but still, alternative modalities without radiation, like ultrasound or MRI, should be considered more often. In countries such as the US, Spain, and Japan, many more CT scans are done in children than in the Netherlands. Our study underscores the importance of carefully weighing the costs and benefits of CT scans."
De Volkskrant wrote this article about Hauptmann's research [in Dutch].