Radiation exposure from imaging in children increased risk of hematologic cancer: NEJM

A new study published in The New England Journal of Medicine showed a link between radiation exposure from medical imaging and a tiny but considerable elevated risk of hematologic cancer in children and adolescents.

Although medical imaging, especially computed tomography (CT), it exposes them to ionizing radiation. There is evidence that cumulative radiation exposure raises the risk of cancer, particularly hematologic malignancies. In pediatric treatment, it is essential to comprehend this relationship to strike a balance between long-term safety and diagnostic advantages. Thus, this study was evaluated the risk of radiation-induced hematologic malignancy in children and adolescents based on medical imaging.

This research tracked a retrospective cohort of 3,724,623 infants born in 6 U.S. health care systems and Ontario, Canada, between 1996 and 2016 until the earliest of the following events: death, cessation of health care coverage, age 21, diagnosis of cancer or benign tumor, or December 31, 2017. Medical imaging radiation exposures to active bone marrow were measured. Continuous-time hazards models were used to evaluate associations between cumulative radiation exposure (as opposed to no exposure) and hematologic malignancies with a 6-month lag.

A total of 2961 hematologic malignancies were identified throughout the course of 35,715,325 person-years of follow-up, mostly lymphoid cancers (2349 [79.3%]), myeloid tumors or acute leukemia (460 [15.5%]), and histiocytic or dendritic cell cancers (129 [4.4%]). Children exposed to at least 1 mGy had an overall mean (±SD) exposure of 14.0±23.1 mGy, whereas children with hematologic cancer had an exposure of 24.5±36.4 mGy.

With a relative risk of 1.41 (95% CI), 1.11 to 1.78 for 1 to less than 5 mGy, 1.82 (95% CI, 1.33 to 2.43) for 15 to less than 20 mGy, and 3.59 (95% CI, 2.22 to 5.44) for 50 to less than 100 mGy, the risk of cancer increased with cumulative dosage.

A higher risk of all hematologic malignancies and the majority of tumor subtypes was linked to the cumulative radiation exposure to bone marrow. Among children exposed to at least 30 mGy (mean, 57 mGy), the elevated cumulative incidence of hematologic malignancies by age 21 was 25.6 per 10,000.

According to our estimates, radiation exposure from medical imaging may have contributed to 10.1% (95% CI, 5.8 to 14.2) of hematologic malignancies in our cohort, with larger risks associated with higher-dose medical imaging procedures like CT. Overall, a dose-dependent increase in the incidence of hematologic malignancies was linked to cumulative radiation exposure from medical imaging throughout infancy.

Source:

Smith-Bindman, R., Alber, S. A., Kwan, M. L., Pequeno, P., Bolch, W. E., Bowles, E. J. A., Greenlee, R. T., Stout, N. K., Weinmann, S., Moy, L. M., Stewart, C., Francisco, M., Kofler, C., Duncan, J. R., Ducore, J., Mahendra, M., Pole, J. D., & Miglioretti, D. L. (2025). Medical imaging and pediatric and adolescent hematologic cancer risk. The New England Journal of Medicine,. https://doi.org/10.1056/nejmoa2502098