Study: CT scan radiation could drive 5% of future cancer cases

Editor's Note

Current US CT scan practices could lead to approximately 103,000 future cancers—nearly 5% of all new annual diagnoses—if utilization and radiation dosing patterns persist, according to a risk modeling study published April 14 in JAMA Internal Medicine. Authors emphasized that although CT is often lifesaving, its risks are underestimated.

The study analyzed 93 million CT exams performed in 2023 on 62 million patients to project cancer risk across age, sex, and CT type, excluding exams performed in the final year of life. The researchers estimated that approximately 103,000 CT-associated cancers will eventually develop among patients exposed in 2023. Although per-scan cancer risk was higher in children, adult imaging contributed the vast majority (91%) of projected cancers due to higher utilization. The cancer types most frequently attributed to CT exposure included lung, colon, bladder, breast, and leukemia.

Among CT types, abdomen and pelvis scans in adults accounted for the greatest burden—37,500 projected cancers (36%)—followed by chest CT. In children, head CTs contributed over half of the projected cases.

Sensitivity analyses incorporating variable dose estimates, pediatric exam proportions, and alternate assumptions yielded a range of 80,000 to 127,000 projected cancers. Even conservative model inputs aligned with the finding that CT is likely a significant contributor to future cancer burden.

Increased imaging volume—up 35% since 2007—along with multiphase scanning and non-pediatric dose settings, likely elevate risks, authors argue, noting that dose reduction, better justification for imaging, and elimination of unnecessary multiphase exams could reduce future harm.