- CT scans, a valuable tool in diagnosing a range of illnesses and complications, could in fact be responsible for around 5% of all cancers diagnosed in the U.S. each year. That would put it in league with some of the most infamous causes of cancer, including cigarette smoking, obesity and alcohol consumption.
- According to researchers, many CT scans are “low-value” and add little information to an individual’s diagnosis.
- The study looked at projections from hospitals in 20 states, and represents a statistical model –– not patient outcomes.
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CT scans, a valuable tool in diagnosing a range of illnesses and complications, could in fact be responsible for around 5% of all cancers diagnosed in the U.S. each year, according to a study recently published in JAMA Internal Medicine.
The study, led by UC San Francisco epidemiology professor Dr. Rebecca Smith-Bindman, analyzed projections from hospitals in 20 states, and looked at 93 million CT scans from 61.5 million patients nationwide in 2023. What they found is that roughly 103,000 cancer diagnoses, representing about 5% of all cancers nationwide, could be linked to CT scans.
“Medical imaging has potential benefits,” said Smith-Bindman, before cautiously adding, “It has potential harms as well, and it’s really important to balance them.”
Why are CT scans such a problem?
According to the researchers, since 2007, the use of CT scans –– otherwise known as computed tomography scans –– have increased by 35%. However, some of these scans, the researchers argue, are “low-value” and do nothing for diagnosing a problem. It’s a gamble to use CT scans when not absolutely necessary, as radiation emitted during the procedure has long been recognized as harmful.
Meanwhile, the amount of radiation a CT scan emits is not standardized, meaning one scanning facility could emit 50 times more radiation than another, despite an operator performing the same procedure.
“There’s nothing you can do about radiation that you’ve been exposed to already. But you want to limit future exposure to cases when you really need it,” Smith-Bindman told NPR.
Looking at a statistical model, not patient outcomes
Following the publication of Smith-Bindman’s study, the American College of Radiology issued a statement clarifying that its findings were based on statistical modeling, not actual patient outcomes, as NPR notes. Likewise, to date, there are no published studies that directly link CT scans to cancer.
What can we do about it?
Nevertheless, that doesn’t mean an individual necessarily has to undergo a CT scan or expose themselves to radiation. According to Smith-Bindman, one way to lower the risk would be to no longer administer “low-value” scans. Additionally, standardizing doses so that patients are getting the lowest possible amount of radiation would help.
“We need patients to ask their doctors, ‘Can you use low dose when you scan me?’ ” Smith-Bindman said. “It’s crazy that patients have to ask for it, but it’s actually really successful.”
Should their projections prove true, CT scans could be one of the leading causes of cancer alongside cigarette smoking, obesity and alcohol consumption, which account for 19%, 7.6% and 5%, of cancer cases, respectively.
