Risk of hematological malignancies from CT radiation exposure in children, adolescents and young adults

A new article by scientists from the International Agency for Research on Cancer (IARC) and partners, published today in Nature Medicine, confirms a clear association between exposure to radiation from computed tomography (CT) scans in young people and an increased risk of haematological malignancies. This is the second article reporting on the risk of cancers in the large international cohort of children and young adults who underwent CT examinations (the EPI-CT cohort); the first report was on brain cancers.

The new study shows that a radiation dose of 100 milligray to the bone marrow from CT scans increased the risk of developing a haematological malignancy by a factor of about 3. It suggests that a typical CT scan today (with an average dose of about 8 milligray) increases the risk of developing lymphoid or myeloid malignancies by about 16%. This means that among 10 000 children who receive one CT examination, about 1–2 radiation-associated haematological malignancies are expected to occur during the 12 years after the examination.

“This study is an important contribution to the scientific evidence for strengthening radiation protection of patients and the general public,” says IARC scientist Dr Ausrele Kesminiene, the coordinator of the EPI-CT study in IARC’s Environment and Lifestyle Epidemiology Branch. The Branch Head, Dr Joachim Schüz, adds, “Although use of CT examinations for diagnosis, treatment planning, and disease follow-up is highly beneficial to patients, the EPI-CT study shows the need for individual medical justification of a CT examination and for decreasing the applied radiation dose of examinations as much as is reasonably achievable.”

More than 1 million children in Europe undergo CT scans every year. Radiation doses from CT scans have decreased substantially in recent years. Nevertheless, the findings of this study underline the need to continue raising awareness among the medical community. This is because the public’s exposure to ionizing radiation has increased in recent decades, even doubling in some countries, primarily due to increases in medical imaging procedures.

This new article marks another milestone in the EPI-CT study, coordinated by IARC, which has followed up nearly 1 million children and young adults from 276 hospitals in 9 European countries. The analysis of haematological malignancies was led by ISGlobal.

Bosch de Basea M, Thierry-Chef I, Harbron R, Hauptmann M, Byrnes G, Bernier M-O, et al.
Risk of hematological malignancies from CT radiation exposure in children, adolescents and young adults
Nat Med, Published online 9 November 2023;
https://doi.org/10.1038/s41591-023-02620-0