A shocking new study suggests that a routine diagnostic procedure that is performed millions of times annually in the US could cause over 100,000 new cases of cancer annually — with almost 10,000 cases in children.
New research by the Institute of Cancer Research in London indicates that computed tomography scans — which are used to screen for a wide variety of problems, including cancer — could account for 5% of cancer cases in the US.
This would place the cancer-causing risk of CT scans on roughly the same level as alcohol.
The researchers noted that their findings weren’t especially relevant in the UK, which has one of the lowest rates of CT scans in the developed world due to its strict policy of only allowing the procedure when it’s clinically necessary.
The US is a different story.
An estimated 93 million CT scans were performed in the US in 2023, up from 3 million in 1980.
Study co-author Amy Berrington, leader of the Clinical Cancer Epidemiology Group at the ICR, and her team calculated that these CT scans could result in 9,700 cancer cases in American children.
As such, researchers stress the importance of avoiding unnecessary scans and ensuring appropriate doses — especially since the risk is higher in younger patients.
“While CT scans are immensely beneficial in diagnosing and detecting many conditions, including cancer, they do involve exposure to ionizing radiation that has been shown to increase the risk of developing cancer,” Berrington said in a statement.
“It’s important to note that for the individual patient, this increased risk is small, and the benefits far outweigh the risks if the scan is clinically justified. But when millions of CT scans are being carried out across the population, these small risks do add up,” she said.
The researchers also advise medical professionals to remain vigilant about the potential risks and discourage healthy individuals from undergoing full-body scans offered by private clinics.
“We are urging doctors to ensure that scans are only carried out where necessary, and that doses are appropriate for the patient,” Berrington said.
“In the US, CT-related cancers could now account for 5% of all cancers — some of these cancers could be prevented by avoiding unnecessary scans and ensuring correct doses are used.”
How much radiation do you get from a CT scan?
Last month, researchers sounded the alarm that radiation doses from CT scans vary widely among clinics — with little oversight.
“Many patients still routinely receive radiation doses two or three times what they should,” Dr. Rebecca Smith-Bindman, a professor at the University of California-San Francisco medical school, told NBC. “We keep doing more and more CTs, and the doses keep going up.
“It’s unfathomable,” she added.
Smith-Bindman noted that the dose of radiation a patient gets from one machine could be 10 or 15 times as much as another.
In 2009, she and other researchers estimated that the radiation is to blame for 2% of cancers.
Getting multiple CT scans has also been shown to increase cancer risk. In one 2009 study, scientists found that lifetime cancer risk for people who undergo a single CT scan is only 0.7% higher than the general population’s 45% — but have multiple scans, and odds shoot up to 2.7% to 12% more.
Another study determined that people who undergo a CT scan before 22 are at a significantly higher risk for developing blood cancers, while repeated head CTs in childhood have been linked to higher brain tumor risk.
New rules implemented by the Centers for Medicare and Medicaid Services in January mandate stricter assessments of CT scan doses, among other measures.
