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Cited by 2,029Radiation Dose and ImagingEffects of Radiation ExposureGlobal Cancer Incidence and Screening

Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians

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Mathews, J. D., Forsythe, A. V., Brady, Z., Butler, M. W., Goergen, S. K., Byrnes, G. B., Giles, G. G., Wallace, A. B. +7 more·2013·BMJ
DOI 10.1136/bmj.f2360PMC PMC3660619
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Abstract

OBJECTIVE: To assess the cancer risk in children and adolescents following exposure to low dose ionising radiation from diagnostic computed tomography (CT) scans. DESIGN: Population based, cohort, data linkage study in Australia. COHORT MEMBERS: 10.9 million people identified from Australian Medicare records, aged 0-19 years on 1 January 1985 or born between 1 January 1985 and 31 December 2005; all exposures to CT scans funded by Medicare during 1985-2005 were identified for this cohort. Cancers diagnosed in cohort members up to 31 December 2007 were obtained through linkage to national cancer records. MAIN OUTCOME: Cancer incidence rates in individuals exposed to a CT scan more than one year before any cancer diagnosis, compared with cancer incidence rates in unexposed individuals. RESULTS: 60,674 cancers were recorded, including 3150 in 680,211 people exposed to a CT scan at least one year before any cancer diagnosis. The mean duration of follow-up after exposure was 9.5 years. Overall cancer incidence was 24% greater for exposed than for unexposed people, after accounting for age, sex, and year of birth (incidence rate ratio (IRR) 1.24 (95% confidence interval 1.20 to 1.29); P<0.001). We saw a dose-response relation, and the IRR increased by 0.16 (0.13 to 0.19) for each additional CT scan. The IRR was greater after exposure at younger ages (P<0.001 for trend). At 1-4, 5-9, 10-14, and 15 or more years since first exposure, IRRs were 1.35 (1.25 to 1.45), 1.25 (1.17 to 1.34), 1.14 (1.06 to 1.22), and 1.24 (1.14 to 1.34), respectively. The IRR increased significantly for many types of solid cancer (digestive organs, melanoma, soft tissue, female genital, urinary tract, brain, and thyroid); leukaemia, myelodysplasia, and some other lymphoid cancers. There was an excess of 608 cancers in people exposed to CT scans (147 brain, 356 other solid, 48 leukaemia or myelodysplasia, and 57 other lymphoid). The absolute excess incidence rate for all cancers combined was 9.38 per 100,000 person years at risk, as of 31 December 2007. The average effective radiation dose per scan was estimated as 4.5 mSv. CONCLUSIONS: The increased incidence of cancer after CT scan exposure in this cohort was mostly due to irradiation. Because the cancer excess was still continuing at the end of follow-up, the eventual lifetime risk from CT scans cannot yet be determined. Radiation doses from contemporary CT scans are likely to be lower than those in 1985-2005, but some increase in cancer risk is still likely from current scans. Future CT scans should be limited to situations where there is a definite clinical indication, with every scan optimised to provide a diagnostic CT image at the lowest possible radiation dose.

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  • The EPI-CT study was designed to address previous methodological criticisms and limitations of similar studies.

    “EPI-CT was designed to address previous methodological criticisms and limitations of similar studies12–16.”

    From Risk of hematological malignancies from CT radiation exposure in children, adolescents and young adults (2023) · cites this paper as [13]

    The Methods and Strengths and limitations sections describe the Australian CT cohort and its limitations, but do not discuss EPI-CT’s design. Searches for “EPI-CT” and for methodological criticisms of similar studies found no passage addressing the claim in our copy; page numbers were unavailable. (LLM, conf=0.75)

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  1. World Health Organization, International Agency for Research on Cancer. Ionizing radiation, part 1:x-and gamma (γ)-radiation, and neutrons. IARC Monogr Eval Carcinog Risks Hum 2000;75:1-492.
  2. Shrimpton PC, Hillier MC, Lewis MA, Dunn M. Doses from computed tomography (CT) examinations in the UK-2003 review. NRPB-W67. National Radiological Protection Board, 2005.
  3. Huda W, Ogden KM. Computing effective doses to pediatric patients in Computed Tomography. Pediatr Radiol 2008;38:415-23.
  4. Jackson D, Ditchfield M, Goergen SK. Trans-Tasman CT dose audit. Asian Oceanian Congress of Radiology, Royal Australian and New Zealand College of Radiologists Annual Scientific Meeting, 2 September 2012. Wiley, 2012.
  5. All cancers, except brain cancer after brain CT IRR=incidence rate ratio, exposed v unexposed; EIR=absolute excess incidence rate compared with rates in unexposed group. *IRR, EIR, and number of excess cancers calculated after stratification for age, sex, and year of birth. No commercial reuse: See rights and reprints http://www.bmj.com/permissions Subscribe: http://www.bmj.com/subscribe Minerva Access is the Institutional Repository of The University of Melbourne Author/s:
  6. Mathews, J. D., Forsythe, A. V., Brady, Z., Butler, M. W., Goergen, S. K., Byrnes, G. B., Giles, G. G., Wallace, A. B., Anderson, P. R., Guiver, T. A., McGale, P., Cain, T. M., Dowty, J. G., Bickerstaffe, A. C. & Darby, S. C. (2013). Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians. BMJ-BRITISH MEDICAL JOURNAL, 346 (7910), https://doi.org/10.1136/ bmj.f2360. Persistent Link: http://hdl.handle.net/11343/116318 License: CC BY-NC

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Authors
Mathews, J. D., Forsythe, A. V., Brady, Z., Butler, M. W., Goergen, S. K., Byrnes, G. B., Giles, G. G., Wallace, A. B., Anderson, P. R., Guiver, T. A., McGale, P., Cain, T. M., Dowty, J. G., Bickerstaffe, A. C., & Darby, S. C.
Affiliations
  • The University of Melbourne (AU)
  • Department of Health and Aged Care (AU)
  • Monash University (AU)
  • Centre international de recherche sur le cancer (FR)
  • Cancer Council Victoria (AU)
  • Australian Radiation Protection and Nuclear Safety Agency (AU)
  • Australian Institute of Health and Welfare (AU)
  • University of Oxford (GB)
  • Royal Children's Hospital (AU)
Corresponding author
Mathews, J. D.
ORCID
Venue
BMJ
Publisher
BMJ
Published
2013-05-21
Volume
346
Issue
may21 1
Pages
f2360-f2360
ISSN
1756-1833 (ISSN-L)
DOI
10.1136/bmj.f2360
PMC
PMC3660619
OpenAlex
W2130876592
Cited by
2,029
References
53
Citations by year
2026: 74 · 2025: 100 · 2024: 120 · 2023: 131 · 2022: 134 · 2021: 201 · 2020: 177 · 2019: 153 · 2018: 152 · 2017: 173 · 2016: 176 · 2015: 195 · 2014: 186 · 2013: 50 · 2012: 1
FWCI
157.05
Type
journal article
Language
en
Open access
Licence
cc-by-nc
Locations
  • BMJ (publishedVersion, cc-by-nc)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by-nc)
  • PubMed Central (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
  • Minerva Access (University of Melbourne) (submittedVersion, cc-by-nc)
  • Minerva Access (University of Melbourne) (submittedVersion)
Funders
  • Australian Government
  • Cancer Research UK
Topics
  • Health Sciences › Medicine › Radiology, Nuclear Medicine and Imaging › Radiation Dose and Imaging
  • Health Sciences › Medicine › Radiology, Nuclear Medicine and Imaging › Effects of Radiation Exposure
  • Health Sciences › Medicine › Oncology › Global Cancer Incidence and Screening
Keywords
computed tomography, pediatric radiation exposure, low-dose radiation, cancer risk, cancer incidence, dose-response relationship, age at exposure, time since exposure, solid tumors, leukemia, myelodysplastic syndrome, lymphoid cancer, melanoma, thyroid cancer, radiation-induced cancer, diagnostic imaging safety, Australia, Medicare claims data, cancer registry
MeSH terms
Adolescent, Australia, Child, Child, Preschool, Epidemiologic Methods, Female, Humans, Infant, Male, Neoplasms, Radiation-Induced, Radiation Dosage, Socioeconomic Factors, Time Factors, Tomography, X-Ray Computed, Age Distribution, Sex Distribution, Young Adult

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