More than 100,000 future cancer cases were projected to result from the 93 million CT examinations performed in 2023, according to a study published April 14 in JAMA Internal Medicine.
Low-dose CT scans are the recommended screening method for lung cancer. Though lung cancer screening rates lag behind colorectal and breast cancer screenings, recent guideline changes have seen lung cancer screening uptake triple in recent years.
Prevention and screening efforts were collectively responsible for averting 80% of breast, cervical, colorectal, lung and prostate cancer deaths between 1975 and 2020.
For the study, a team of researchers, led by the University of California San Francisco, projected the number of future cancer cases associated with CT scans using 2023 patient data, the UCSF CT dose registry and National Cancer Institute software to quantify biological effects of radiation. The information was then scaled to apply to the total U.S. population.
Here are five things to know from the study:
- Approximately 93 million CT scans were performed for almost 62 million patients in 2023. Of those patients, 95.8% were adults and 4.2% were children.
- About 103,000 radiation-induced cancer cases were projected to result from the 93 million scans, of which 93,000 would occur in adults.
These projected cases would account for 0.17% of the 62 million patients who underwent CT scans in 2023. - Of the 103,000 projected cancer cases, 37% were projected to result from adult abdominal and pelvic CT scans and 23% were projected to stem from chest CT scans.
- Of the 103,000 projected cancer cases, 22,400 were lung cancer, 8,700 were colon cancer, 7,900 were leukemia and 7,100 were bladder cancer for both men and women. Among women, there were 5,700 projected breast cancer cases.
- “If current practices persist, CT-associated cancer could eventually account for 5% of all new cancer diagnoses annually,” the study authors wrote.
The American College of Radiology responded to the study in an April 14 statement shared on the organization’s website.
“The theoretical radiation risk proposed by Smith-Bindman, et al, is consistent with prior statistical modeling studies that are not based on actual patient outcomes,” the statement said. “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.”
Read the full study here.
