CT radiation exposure could account for 5% of future cancer diagnoses
A large new analysis offers a fresh take on how computed tomography utilization will affect cancer rates in the future.
Published in JAMA Internal Medicine, the new paper provides detailed projections of future cancer diagnoses in the United States. Researchers pooled data on radiation doses, patient demographics and CT utilization from millions of scans completed in the U.S. during 2023 to make their estimations.
According to the team’s calculations, the nearly 100 million CT scans conducted in the U.S. during 2023 will result in approximately 103,000 future cancer diagnoses annually due to radiation exposure alone.
“CT is frequently lifesaving, yet its potential harms are often overlooked, and even very small cancer risks will lead to a significant number of future cancers given the tremendous volume of CT use in the United States,” Rebecca Smith-Bindman, MD, with the department of epidemiology and biostatistics at the University of California, San Francisco, and colleagues explain.
The team incorporated a large multi-center sample of CT data into their risk assessment. This included data from more than 93 million CT scans on 61,510,000 patients, including 2,570,000 children and 58,940,000 adults.
Although cancer risks are higher in children, a greater percentage of the group’s estimate is owed to increased utilization among adult patients, at approximately 90%. The projections predict lung cancer will be the most prevalent diagnosis, with 20,200 to 25 000 cases, followed by colon cancer with 7,800 to 9,700 cases, leukemia, at 7,900 cases and bladder cancer, tallying between 6,000 and 8,500 diagnoses.
Women face slightly different risks. Breast cancer is predicted to be the second most prevalent diagnosis for females, with the team estimating there will be between 5,000 and 6,500 cases annually.
Researchers determined that CT scans of the abdomen and pelvis in adults will be the greatest driver of cancer diagnoses, followed by chest CTs.
“To provide context, if the number of new cancer diagnoses in the United States remains stable (1.95 million in 2023) and both the utilization and radiation doses from CT remain unchanged in future decades, CT could be responsible for approximately 5% of cancers diagnosed each year,” the authors note. “This would place CT on par with other significant risk factors, such as alcohol consumption (5.4%) and excess body weight (7.6%).”
The authors suggest their estimations, which around three times higher than previously published data on the same subject, could be owed, at least in part, to both the aging population that requires more extensive medical care and low value/inappropriate imaging requisitions. They also attribute new dosimetry methods with more accurate estimations of radiation doses to the higher figures.
In response to the study’s publication, the American College of Radiology released a statement indicating that the researchers’ findings are on par with other statistical modeling studies, but emphasized that the results are not derived from actual patient outcomes.
“The National Council on Radiation Protection and Measurement has reported that even with increased CT use, advances in technology and imaging protocol optimization have reduced population radiation burden (medical radiation dose per capita/person),” the statement reads. “There are no published studies directly linking CT scans (even multiple CT scans) to cancer. Americans should not forgo necessary, life-saving medical imaging and continue to discuss the benefits and risks of these exams with their healthcare providers.”
Learn more about the study’s findings here.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.