[Intl_DxMedPhys] Heads up on NEJM paper on radiation exposure in peds and hematologic cancer risk

[Li, Baojun]

If we replace “accumulative dose to bone marrow” with “total number of blood draws or hospital visits,” the relationship would likely still hold. By the authors’ reasoning, one could then conclude that blood draws or hospital visits cause cancer?!

In reality, children who undergo multiple CT examinations typically do so because of more severe or complex medical conditions. These patients are inherently predisposed to more hospital encounters and already have a higher baseline risk of hematologic malignancies, independent of imaging. The causal inference presented by the authors is deeply flawed and misleading.

Thanks,
Baojun


From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces+baojunli=bu.edu at lists.osu.edu> On Behalf Of Mark Supanich via Intl_dxmedphys_wd_osu_list
Sent: Wednesday, September 17, 2025 6:35 PM
To: intl_dxmedphys_wd_osu_list at lists.osu.edu
Subject: [Intl_DxMedPhys] Heads up on NEJM paper on radiation exposure in peds and hematologic cancer risk

Hi all, Just a heads up that NEJM published a paper from Smith-Bindman et al this afternoon. https: //www. nejm. org/doi/full/10. 1056/NEJMoa2502098?query=featured_home It’s an observational study of 3. 5+ million peds looking at cumulative
Hi all,


Just a heads up that NEJM published a paper from Smith-Bindman et al this afternoon. https://urldefense.com/v3/__https://www.nejm.org/doi/full/10.1056/NEJMoa2502098?query=featured_home__;!!KGKeukY!yHEZTng9rxNmpcKSbWb2A8pvdyzOePYAgWmasGWBEeQTM2jgCSwhaCxDkPgxZa19AbNBPMuW3AM3x41vCr2WBtNZYe90AeW-rPeN2Ao$ <https://urldefense.com/v3/__https:/www.nejm.org/doi/full/10.1056/NEJMoa2502098?query=featured_home__;!!KGKeukY!1m_oRWHMFCepm1fT1RIhzq46cPRXjfbhAvYKAO_5iNUOWD5mqN0G-iBdtAZYZy1h5_JOVRouzbgwoLM5N75lJAFaFMiQA3UTRzxHR2RjJ7wH4P8$>

It’s an observational study of 3.5+ million peds looking at cumulative exposure to ionizing radiation, particularly focused on bone marrow dose, and increased risk of hematologic cancer incidence. Their results claim an increased incidence of cancer in patients with exposure to imaging, and demonstrate a cummulative dose effect. They claim their results are not likely due to reverse causation as they have reasons for exams and symptoms of these cancers were not common reasons for exams. They also note their results are inline with the EPI-CT study. Of note, it appears that they looked at imaging from 1996-2017 – so much of the imaging likely occurred on imaging equipment without many of the modern dose reduction features.

This is sure to get media play and parents will certainly have questions as the media coverage develops. Continuing to focus on the judicious use of imaging, the benefits of diagnostic imaging to answer clinical questions, and the fact that modern imaging equipment adapts to patient size and uses optimized radiation will be key talking points.

>From the paper: “By the end of follow-up, 7.5% (280,548 of 3,724,623) of all the children and 9.2% (272 of 2961) of those in whom a hematologic cancer developed had received a cumulative dose of at least 1 mGy.”

[cid:image002.png at 01DC296C.75EA04F0]

There is a lot to look at in this paper and the supplemental materials, so more information/analysis is sure to come.
--
Mark P. Supanich, Ph.D., DABR, FAAPM (he/him)
Director – Diagnostic Medical Physics
Rush University System for Health
Associate Professor & Vice Chair for Physics and Informatics
Rush Medical College Department of Diagnostic Radiology and Nuclear Medicine
[RUSH]

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