CT Scans And Cancer Risk

” Yesterday’s news,” my husband said when I shared a study published, well, yesterday. Yet what we do with yesterday’s information is of course the news today. A JAMA Pediatrics article found that the use of pediatric CT scans rose in the late 1990’s and early 2000’s. Further, research shows that these CT scans can increase risk for future cancer diagnoses. Authors calculated the risk: they estimate that for every 4 million pediatric CT scans preformed annually, some 4800 children will go on to develop cancer as a result. Like many studies published this decade, the study came with warnings for radiologists, pediatricians, and parents.  I have tips for parents and doctors included below.
CT scans use radiation and radiation exposure is linked to cancer.
That being said, CT scans also save lives and we’re learning to use them more judiciously. Since 2007, rates of CT scans in children are declining. Don’t let these risks and media reports today cause you refuse or forego diagnostic CT scans your children need. We just have to be strong advocates and smarter about how we use CT scans. Here’s a well stated reminder authored today from The American College of Radiology:

Medical imaging exams are directly linked to greater life expectancy, declines in mortality rates, and are generally safer and less expensive than the invasive procedures that they replace, such as exploratory surgery. Diagnostic scans reduce the number of invasive surgeries, unnecessary hospital admissions and the length of hospital stays. However, they must be used judiciously, when indicated, and when the needed information cannot be obtained in other ways, in order to minimize radiation exposure to all Americans — particularly children.

The JAMA Pediatrics article outlines data from diverse populations of children in the US that demonstrate the increased cancer risk for children after CT scans. The findings provoked significant media attention. Most media summaries focused on the numbers offered in the study—that every year there are thousands of children who receive CT scans that will ultimately develop a solid tumor or blood cancer in their lifetime and the CT scan they’ve had may be in part to blame. The study also found that radiation doses varied (from 0.03 mSv per scan up to 69.2 mSv per scan). Researchers found that high dose was delivered in about 14-25% of abdominal pediatric CT scans and in 3-8% of chest CT scans. While using a risk calculus from data obtained in survivors of the atomic bomb, researchers estimated that for the 4 million pediatric CT scans done each year in the US, the scans could potentially cause over 4000 cases of future cancer. The study affirms what others have found previously; even one CT scan in early childhood can increase the lifetime cancer risk for a child. Researchers further postulate that pediatricians, radiologists and families can work together to reduce the highest ¼ of doses of CT scans delivered so that we may prevent 43% of the future cancer risk. That’s something to fight for.
Reducing radiation and CT scans for children is a priority because effects for young children can last their entire lifetime (many years to come) and because children’s bodies are developing and thus more at risk from the potentially damaging effects of radiation on cells.
The information from the study is scary more than anything else. It’s particularly frightening to those parents whose children have had a CT scan (or many) in their lifetime. And although I work furiously to protect my children and my patients from unnecessary radiation and CT scans, we cannot forget the significant number of children whose lives are saved by CT scan diagnosis, as well.
Like everything in health care, there is a complex balance of risk and benefit that goes into each decision we make. Going forward, advocate for your children to get CT scans only when necessary.
Sometimes the “watch and wait” approach is a powerful and safe approach. Sometimes we don’t need to get a CT scan. Sometimes we really do. As parents, it may not feel like a decision you want or have to make—and that’s true, too. Your job is to speak up and ask questions.
The good news: rates of CT scans for children have been declining in the United States since 2007. This is likely secondary to ongoing research (like that published yesterday) and efforts from the Image Gently campaign—a campaign started in 2007 by pediatric radiologists designed to lower CT scans dose through education and thoughtful protocols. The Image Gently campaign has protocols for radiologists and hospitals to decrease the dose for all children receiving CT scans. They also have a site for parents.
The bad news: the study illuminated that health care can change rapidly. During the years between when I graduated from college (1996) and had my first son (2006), there was a tremendous rise in the number of CT scans—the rates tripled for children. Further, some children weren’t protected as well as they could have been. In reviewing data on CT scans in children researchers uncovered significant variability in the dose the children receive when they get a CT scan. That means some children got more radiation than others for the same CT scan. I’ve written previously that where you get a CT scan matters. In general, obtaining a CT scan at a children’s hospital or pediatric facility will improve the likelihood they receive the lowest dose possible.
When it comes to CT scans, we want our children treated with kid gloves. We want to use the lowest dose of radiation to determine the diagnosis.

Tasks For Parents:

• If your child is offered a CT scan for diagnosis of a medical condition or injury, inquire immediately if an alternative diagnostic test exists. Research has found that up to 1/3 of pediatric CT scans are unnecessary. Ask the doctor if an ultrasound or MRI scan (both deliver no radiation) could determine the question at hand. Ask the doctor if it would be safe to wait and see how your child does over coming days without a CT or if it is urgent that a scan be completed to protect them.
• If your child needs a CT scan, ensure the technologist and radiologist are using the lowest dose possible. However uncomfortable it may seem, it’s always okay to ask if your child is getting lowest dose of radiation possible. Ask the radiologist or technologist if they are following the Image Gently protocol. If they don’t know, ask to talk with the doctor. The reality is, the study found significant variability in dose of radiation between children and CT scans. Children are smaller and typically require less intense radiation compared with adults. Make sure in this regard they are treated with kid gloves. DEMAND that those doing a CT are using the lowest dose possible. This study, for example, found that abdominal/pelvic CT scans conferred the highest risk for cancer causing radiation. 11% of abdominal CT scans completed in the study were obtained to rule-out appendicitis. However, children can typically get an ultrasound to diagnose appendicitis. This is where ordering physicians and families can work together to use alternative studies when possible.
• Keep a record of the X-rays and CT scans your child has like you keep a record of their immunizations.  Print this x-ray record out today.

Tasks For Doctors To Reduce Radiation:

• Pediatricians can inquire with their hospitals, emergency rooms, and urgent care centersto determine if those facilities are following the Image Gently protocol. We can work to refer children for CT scans only when necessary and only in facilities that work to reduce dose of radiation. Pediatricians can work to educate families on how to reduce the use of CT scans and empower their families that if ever in an emergency situation or medical scenario where a CT is offered that families ask about dose and alternative studies.
• Pediatricians can work to use CT scans only when necessary. We must think about how and why we look for diagnoses and answers with CT scans and we must consider the lifetime risks for our patients. We must facilitate easy access to follow-up care if it potentially allows us to monitor patients closely and avoid unnecessary scans with radiation.
• Make sure your institution is a part of the Dose Registry. As Dr Jonathan Swanson explains, “The ACR Dose Index Registry is a fledgling tool to help facilities compare their CT doses to national benchmarks. The feedback built into the registry allows health care centers to adjust dose accordingly and gauge how their radiation reduction efforts are working over time. It provides a useful check for facilities that image children and adults to determine if they are effectively ‘child-sizing’ the CT dose for children.”

Sometimes we will have to wait without conclusive results from CT scans to protect our children. Although somewhat heavy-handed, I really enjoyed the associated editorial’s conclusion entitled The Harm In Looking:

Uncertainty can be unsettling, but it is a small price to pay for protecting ourselves and our children from thousands of preventable cancers.

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