Fetal exposure to radiation and the risk of childhood cancer:
What is the likelihood of a risk?
ADIT, septembre

Contact: Katie Hickling
Public Library of Science
Press release from PLoS Medicine

     A new study published in this week's PLoS Medicine aims to evaluate the possibility that exposure of a fetus to computed tomography or radionuclide imaging performed during pregnancy might increase subsequent risk of childhood cancer. The researchers concluded that despite the very large size of their study they were unable to exclude the possibility of a very slight risk, and advise that beta hCG testing (blood pregnancy test) should continue to be done in all potentially pregnant women before undergoing major radiodiagnostic testing. Similarly, use of lead apron shielding of the pelvic area of pregnant women is also recommended. The research was carried out by Joel Ray and colleagues from St. Michael's Hospital, Toronto, Canada, and colleagues.
     The authors used an anonymized database for the whole province of Ontario, Canada (where universal health care is available to all residents) to link maternal radiation exposure to a subsequent malignancy in the child. Using this technique, the authors were able to follow up 1,835,517 mother-child pairs. In the entire dataset, 5,590 women were exposed to radiodiagnostic testing during pregnancy; amongst the children born to these exposed women, there were a total of four subsequent childhood cancers. There were 1,829,927 women in the unexposed group (who did not have radiodiagnostic imaging during pregnancy), and 2,539 cancers were found amongst the children born to these women. The rates of childhood cancer in exposed versus unexposed groups corresponds to a crude hazard ratio of 0.69. However, there was still substantial uncertainty in this study around the relative risk of malignancy following radiodiagnostic testing. The researchers estimated an "adjusted hazard ratio" for the risk to be 0.68, with confidence limits between 0.25 and 1.80. These confidence intervals (representing uncertainty) suggest that although the researchers did not find clear evidence for an increase in risk following imaging, they could not exclude the chance of a small increase, up to 1.8 times that in an unexposed pregnancy.
     Given this possibility the authors recommend that radiodiagnostic testing should be performed in pregnancy under urgent or emergency situations, but that nonradiation-emitting imaging, such as MRI and ultrasonography, be considered first, when clinically appropriate. It should be emphasized that this study relates to the use of imaging modalities such as computed tomography (and other forms of radionuclide imaging), typically carried out to diagnose or exclude conditions encountered during an emergency, such as pulmonary embolism or stroke – and not the routine ultrasound scans done during pregnancy.
     In an accompanying Perspective, Eduardo Franco and Guy-Anne Turgeon from McGill University, Montreal, Canada recommend that that an international consortium be formed to attempt to pool the data on exposure-risk associations from all available investigations to shed more light into this issue and assist policymakers in the future.

Funding: This study was funded by the Pediatric Oncology Group of Ontario (POGO). JGR and AG are supported by Canadian Institutes for Health Research New Investigator Award. This study was supported by the Institute for Clinical Evaluative Sciences (ICES), which is funded by the Ontario Ministry of Health and Long-Term Care (MOHLTC). The opinions, results, and conclusions reported in this paper are those of the authors and are independent from the funding sources. No endorsement by ICES or the Ontario MOHLTC is intended or should be inferred. No funding bodies had any role in the study design, data collection, analysis, decision to publish or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
Citation: Ray JG, Schull MJ, Urquia ML, You JJ, Guttmann A, et al. (2010) Major Radiodiagnostic Imaging in Pregnancy and the Risk of Childhood Malignancy: A Population-Based Cohort Study in Ontario. PLoS Med 7(9): e1000337. doi:10.1371/journal.pmed.1000337
Joel Ray
University of Toronto
30 Bond St
Toronto, ON M5B 1W8
416 864-6060 Ext 6752
416 864-5485 (fax)
Julie Saccone
Senior Public Relations Specialist
St Michael's
Related PLoS Medicine Perspective by Eduardo Franco and Guy-Anne Turgeon:
Funding: No specific funding was received for this article.
Competing interests: Eduardo Franco is on the Editorial Board of PLoS Medicine.
Citation: Franco EL, Turgeon G-A (2010) Radiodiagnostic Imaging in Pregnancy and the Risk of Childhood Malignancy: Raising the Bar. PLoS Med 7(9): e1000338. doi:10.1371/journal.pmed.1000338
Eduardo Franco
McGill University
Division of Cancer Epidemiology
546 Pine Avenue West
Montreal, QC H2W1S6
1-514-398-5002 (fax)
NY raises awareness of CT radiation risks in pediatrics

September 07, 2010
by Heather Mayer, DOTmed News Reporter

     The New York State Department of Health hopes to raise awareness about radiation safety issues associated with computed tomography imaging of children. The department said last week it will start issuing pamphlets and child medical imaging cards, as part of the "Image gently campaign: Working to change practice."
     The campaign kicked off in 2007 by the Alliance for Radiation Safety in Pediatric Imaging.
     The state's DOH has partnered with the campaign to raise awareness about potential radiation exposure risks from CT procedures and advocate the use of low radiation doses when imaging children.
     The education materials are being provided to 16,000 pediatricians and physicians throughout the state, who will then distribute them to parents and patients, the DOH said.
     "CT imaging is an effective and widely used diagnostic tool, but it should be performed in a manner that reduces any undue risks to patients, especially children," said the state's health commissioner, Dr. Richard Daines, in a statement. "Parents should be aware of radiation safety issues for children and talk to their physicians about which imaging options are appropriate for their child."
     The educational pamphlet includes basic information regarding X-rays and CT scans, their associated risks and the best scanning strategies to reduce risks without compromising image quality. The imaging card will allow parents to track dates and locations of imaging exams, as well as the pediatrician's name and contact information.
     "We are very pleased that New York has recognized and promoted participation in the Image Gently campaign," said Shawn Farley, director of public affairs for the American College of Radiology, in an e-mail to DOTmed News.
     In order to reduce radiation exposure in the pediatric population, New York's DOH and other health care groups promote using alternative, non-radiation diagnostic imaging such as MRI and ultrasound, limiting multi-slice CT imaging to specified areas and avoiding multiple scans. The department also recommends using the lowest dose of radiation based on factors such as the child's age and size, and encourages CT facilities to obtain accreditation from ACR's CT accreditation program.
     "Physicians should carefully weigh the benefits of multi-slice CT scans versus alternative medical imaging procedures when treating children and limit radiation dosages whenever possible," said Daines. "As the use of CT scans continues to grow, we need to ensure that a child's safety remains the top priority."
     The number of CT scans performed in the United States is increasing 10 to 15% every year. It has grown from 3 million scans in 1980 to 62 million in 2006. About 7 million CT exams are performed on children each year, including 33% on children under the age of 10, according to New York's DOH.

Interested in Medical Industry News? Subscribe to DOTmed's weekly news email and always be informed. Click here, it takes just 30 seconds