Risks of leukemia, intracranial tumours and lymphomas in childhood and early adulthood after pediatric radiation exposure from computed tomography

Q: What was the primary objective of the study?

To evaluate whether CT radiation exposure during childhood (at or before 18 years) is associated with subsequent risks of intracranial tumours, leukemia, or lymphoma across different pediatric age groups and into early adulthood.

Q: How did the researchers define exposure to CT radiation?

CT scans were considered as exposure if received at or before 18 years of age and at least 3 years before the index date, using the total number of CT scans received within that timeframe.

Q: What did the study find about risk after a single pediatric CT scan versus multiple CT scans?

A single pediatric CT scan did not increase the risk of intracranial tumours, leukemia, or lymphoma compared with no exposure. In contrast, having 4 or more CT scans was associated with an elevated incidence of cancer outcomes, with the highest risks among children exposed at 6 years or younger.

Sep 24, 2026

Uploaded by Noah

Children have greater susceptibility to radiation-related harm than adults, yet evidence on cancer risk after computed tomography (CT) in different pediatric age groups is limited. This nested population-based case–control study examines the risk of intracranial tumours, leukemia, and lymphoma in children, adolescents, and young adults (<25 years) following CT radiation received at or before 18 years. Conditional logistic regression with incidence rate ratios estimates associations with single versus multiple CT exposures, stratified by age at exposure and exposure timing.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages9

Reading Time23 min

AccessFree to download

Abstract

Background

Methods

Results

Interpretation

Study context and rationale

Global CT use in children

Radiation risk and oncogenesis

Knowledge gaps and study aim

Methods

Study design and setting

Data source

Additional study procedures

National Health Insurance Research Database (NHIRD) data handling

Research Risks of leukemia, intracranial tumours and lymphomas in childhood and early adulthood after pediatric radiation exposure from computed tomography Wei-Hao Wang MD MSc, Chia-Yu Sung MD, Shih-Chung Wang MD MSc, Yu-Hsuan Joni Shao PhD n Cite as: CMAJ 2023 April 24;195:E575-83. doi: 10.1503/cmaj.221303 Abstract Background: Children are more susceptible to radiation-induced damage than adults, but little research has compared the risk of cancer after exposure to radiation during computed tomography (CT) among children at different ages. We aimed to explore the risk of intracranial tumours, leukemia or lymphoma among children, adolescents and young adults (aged < 25 yr) after radiation exposure from CT at or before the age of 18 years. Methods: We conducted a nested, population-based case–control study using data from Taiwan’s publicly funded health care system. We identified participants younger than 25 years with newly diagnosed intracranial tumours, leukemia or lymphoma, from Jan. 1, 2000, to Dec. 31, 2013. We assigned 10 non-cancer controls for each case, matching by sex, date of birth and day of entry to the cohort. We considered CT scans received at or before the age of 18 years and 3 or more years before the index date (the date of cancer diagnosis for cases) as exposure. We used conditional logistic regression models and incidence rate ratios (IRRs) to estimate the relationship between risk of these cancers and CT radiation exposure. Results: We identified 7807 cases and matched to 78 057 controls. Compared with no exposure, exposure to a single pediatric CT scan did not increase risk of intracranial tumours, leukemia or lymphoma . However, participants exposed to 4 or more CT scans had an elevated incidence (IRR 2.30, 95% confidence interval 1.43–3.71) of one of the cancer outcomes of interest. Receiving 4 or more CT scans at or before 6 years of age was associated with the highest risks of cancer, followed by ages 7–12 years and 13–18 years (p for trend < 0.001). Interpretation: Exposure to a single CT scan was not associated with increased risks of subsequent intracranial tumours, leukemia or lymphoma among children; however, we observed increased cancer risks among those with 4 or more CT scans, especially among younger children. Although these cancers are uncommon, the findings of this study underscore the importance of prudent use of CT in the pediatric population. The use of computed tomography (CT) in children has increased globally over the past several decades.1–3 In North America, the annual incidence of childhood CT scans plateaued in 2006, followed by a slow decline, but the rate of pediatric CT imaging in the United States and Canada was still higher in 2016 than in 2000.3 Although low-dose (< 500 milliGray) radiation does not cause immediate illness in humans, it inflicts damage to the genome and can induce oncogenesis.4–6 Preclinical cell and animal models have been proposed to illustrate the dose–response effect after low-dose radiation.4,5 Clinical studies have shown that exposure from diagnostic CT is associated with increased risk of cancer among both adults and children,7–13 and that children are more vulnerable to radiation than adults.14 However, studies comparing risk of cancer after CT exposure among children at different ages are limited and have reported conflicting conclusions.7–9,12 It remains unclear how CT exposure at different ages in childhood affects the risk of cancer. In addition, studies that focus on risk of cancer among young adults associated with radiation exposure in childhood are lacking. Compared with cancers among older people, cancers among young adults have © 2023 CMA Impact Inc. or its licensors CMAJ | April 24, 2023 | Volume 195 | Issue 16 E575 Research shown similar manifestations to those in adolescents in terms of the type of cancer, treatment response and prognosis.15–17 Since head CT is the most common type of CT used for childre

FAQs

What was the primary objective of the study?

To evaluate whether CT radiation exposure during childhood (at or before 18 years) is associated with subsequent risks of intracranial tumours, leukemia, or lymphoma across different pediatric age groups and into early adulthood.

How did the researchers define exposure to CT radiation?

CT scans were considered as exposure if received at or before 18 years of age and at least 3 years before the index date, using the total number of CT scans received within that timeframe.

What did the study find about risk after a single pediatric CT scan versus multiple CT scans?

A single pediatric CT scan did not increase the risk of intracranial tumours, leukemia, or lymphoma compared with no exposure. In contrast, having 4 or more CT scans was associated with an elevated incidence of cancer outcomes, with the highest risks among children exposed at 6 years or younger.

Sep 24, 2026

Uploaded by Noah