New study assesses cancer risks associated with CT scans in pediatric patients

In a new study involving data from more than 85,000 people aged 25 or younger, researchers have found that exposure to two or three computed tomography (CT) scans at age 18 or earlier can lead to elevated risks of intracranial tumor, and exposure to radiation therapy for four or more CT scans can lead to significantly increased risks of intracranial tumor, leukemia, and non-Hodgkin’s lymphoma.

Using the National Health Insurance Research Database (NHIRD) in Taiwan, researchers looked at data from 7,807 patients who were diagnosed with intracranial tumors, leukemia, non-Hodgkin’s lymphoma or Hodgkin lymphoma between January 1, 2000 and December 31, 2013, and 78,057 matched control patients, according to the study, which was recently published in the Canadian Medical Association Journal.

The study authors found no evidence of an increased risk of cancer with pediatric radiation exposure related to CT scans. However, the researchers found that two to three pediatric CT scans more than doubled the risk of an intracranial tumor (adjusted odds ratio (OR) 2.36). Four or more CT scans at age 18 or earlier led to a nine-fold increased risk of intracranial tumor (adjusted OR 9.01) as well as significantly increased risks of non-Hodgkin’s lymphoma (adjusted OR 6.76) and leukemia (adjusted OR 4.80) .

“Unnecessary CT scans should be avoided and special consideration should be given to patients who require repeat CT scans. Parents and pediatric patients should be well informed of the risks and benefits before radiological procedures and encouraged to participate in decision-making regarding imaging,” wrote study co-author Wei-Hao Wang, MD, MSc., which is affiliated with the Department of Pediatrics. at Changhua Christian Hospital in Changhua, Taiwan, and the Graduate Institute of Biomedical Information at the College of Medical Science and Technology of Taipei Medical University in Taiwan, and colleagues.

According to the study authors, the overall cancer risks associated with increased exposure to CT radiation were highest in children six years of age or younger. In this population, there was an adjusted overall OR of 22.95 for the above conditions with four or more pediatric CT exposures, an OR of 1.65 with three pediatric CT exposures, and an OR of 1.54 with two pediatric CT exposures .

(Editor’s note: For related content, see “Large multinational study shows link between CT radiation exposure and brain cancer in children and young adults,” “Emerging Advances in PET/CT Imaging in Pediatric Radiology” And “Exposure to iodinated contrast media: is subsequent thyroid monitoring justified for young pediatric patients?”)

The study authors noted that cancer risk increases when recurrent radiation exposure leads to cumulative DNA damage that exceeds DNA repair capabilities. However, they also cautioned that the aforementioned conditions are rare in children and that cancer risks may be overestimated due to confounding risk factors and low numbers of participants in the study’s high-radiation groups.

Regarding confounding risk factors, the researchers acknowledged the lack of sufficient data on smoking, obesity, alcohol consumption, and exposure to pesticides or drugs containing phthalates in the NHIRD database. that they used for the study. They underlined the lack of data on genomic alterations of the germline which would affect approximately 10% of patients with cancers in children or adults. The study authors also admitted that they were unable to detect the possible effects of high doses of radiation due to a small number of patients in the high radiation groups.