Most parents want to know about the lifetime cancer risk posed by doing a CT scan on their child in the emergency department (ED), although it seldom stops them from giving consent for the scan, a study showed.
About half of parents surveyed when their child was seen for a head injury in the ED already knew something about the risk from ionizing radiation with CT scans (47%), Kathy Boutis, MD, of the University of Toronto and its Hospital for Sick Children, and colleagues found.
More than 90% wanted to be informed of potential malignancy risks before proceeding with the scan, but after that disclosure only 6% decided to refuse the CT, the researchers reported in the August issue of Pediatrics.
In order to have those discussions, 'we strongly recommend that physicians be well informed of the benefits and potential risks of CT imaging,' they wrote.
CT scans in the ED have risen fivefold despite the higher radiation dose that children are particularly sensitive to, the group noted.
'It has been suggested that parental desire for a rapid diagnosis is contributing to the increasing use of CT in children and is occurring without their full understanding of the potential risks,' they added.
Their study included 742 parents surveyed when their children (median age 4 years) presented to a tertiary care pediatric ED with an isolated head injury, before any recommendation had been made for CT. Nearly all the children ended up diagnosed with a minor head injury or concussion (97%).
Despite the fact that 12% of the children had a history of prior CT scans, 63% of the parents underestimated the lifetime risk of cancer from the imaging exam.
Parents estimated the risk of a skull radiograph series as similar to that of CT, although the best available evidence from long-term research puts x-ray lower at one in 1,000,000 compared with one in 10,000.
'The latter could result in an inappropriately equal level of concern about radiation exposure and potential malignancy risks when a physician recommends radiographs or CT, which may affect how often parents raise verbal conversations about potential risks from CT,' Boutis and colleagues noted.
'Clinicians may therefore have a greater responsibility to initiate conversations with families about the risks/benefits of CT rather than doing so only when prompted by the patient.'
Initially, 90% of the parents said they were 'very willing' or 'willing' to proceed with a head CT if the emergency physician thought it necessary.
That proportion dropped to 70% ( P<0.0001) after being told 'although we are not sure, it has been estimated that a head CT scan in a child may carry an increased lifetime cancer risk around one in 10,000. It is very important to remember that the information from a CT scan may help a doctor decide how to best care for a child.'
After disclosure, 35% said they would not have second thoughts about CT testing if the doctor thought it was important, whereas 41% would want further discussion with a physician.
Of the 42 parents (6%) who said they would refuse CT testing in the survey based on the disclosure of lifetime cancer risk, eight subsequently got a recommendation from the physician for CT imaging of their child. All went through with it.
Limitations of the study included lack of data on parents' experience with cancer and that the risk information given was brief and without a personal or detailed clinical context, which 'may not reflect what would happen in clinical reality.'
The English-speaking, largely college-educated population of parents surveyed might not generalize to other sociodemographic and clinical scenarios, where knowledge of radiation risks from imaging may be lower, the researchers noted.
The study was supported by the Pediatric Research Academic Initiative at SickKids Emergency (PRAISE) program, funded internally from the Hospital for Sick Children.
The researchers reported having no conflicts of interest to disclose.
