(Health Secrets Newsletter) Today’s diagnostic methods can increase risk of childhood cancers. Children who have undergone CT scans are at an increased risk of developing leukemia and brain cancer according to research funded by the US National Cancer Institute and the UK Department of Health. Depending on the level of radiation children are exposed to, their risk of developing these types of cancers can triple.
The study was conducted over a period of 24 years and aimed to discover whether children that had CT scans were more likely to develop brain tumors or leukemia in the years that followed. It was published in the journal The Lancet.
CT, or computerized tomography, uses x-ray technology to build up a very detailed image of a person’s insides, which can be useful in diagnosing medical conditions or checking for serious injury after an accident, but also exposes the person to high levels of radiation which can increase cancer risk. The levels of radiation the patient is exposed to depend on the age of the patient, the body part or organ being scanned, and the type and age of the scanning equipment used.
The study involved over 175,000 young people under the age of 22 who had undergone a CT scan between a sixteen year time period. The amount of radiation they would have been exposed to was estimated and the patients were grouped accordingly. The group that would have been exposed to the lowest levels of radiation, the equivalent of just one CT scan, was compared with the group that would have been exposed to an equivalent of two to three CT scans, and the group that would have been exposed to an equivalent of five to ten CT scans.
What did the study show?
Over the course of the study, 135 of the participants were diagnosed with brain tumors and 74 participants were diagnosed with leukemia. The incidence of both of these cancers increased with the levels of radiation they were exposed to. Examples of the results included:
- Patients who had been exposed to the equivalent of 2 to 3 CT scans were at three times the risk of developing a brain tumor
- Patients who had been exposed to the equivalent of 5 to 10 CT scans were also at three times the risk of developing leukemia
While it is clear that the risk of developing these cancers does grow significantly with an increase in exposure to radiation, the risk is still very low, and in some cases the benefits of being able to diagnose an immediate condition outweighs the long term risks. However the research does suggest that more thorough guidelines are required and that CT scans should only be used when clinically justified and when other, radiation free diagnostic methods have been tried or ruled out.
Reducing the levels of radiation that children are exposed to if they do need a scan should be a high priority, and modern machines already use a lower dose of radiation than they did in the past, so making sure than scanning equipment is regularly updated is essential.