Computed tomography (CT) scans, essential for diagnosing and monitoring health conditions, carry significant risks despite their lifesaving potential. A new study published in JAMA Internal Medicine has estimated the future cancer risks associated with CT scans, revealing startling figures.
According to the study, data from 93 million CT scans performed on 62 million individuals in 2023 predict that these scans could lead to 103,000 future cancer diagnoses. This alarming estimate represents about 5 percent of the cancers diagnosed annually when aligned with current cancer rates and the present use of CT scans.
The research highlights CT scans as comparable risk factors for cancer development, akin to alcohol consumption and obesity. Lung cancer and colon cancer were identified as the most common cancer types projected to result from these imaging procedures. Notably, the study indicated that abdomen and pelvis CT scans account for the largest number of cancer cases tied to radiation exposure.
Led by epidemiology and biostatistics researchers at the University of California, San Francisco, this study emphasizes the need for cautious and justified use of CT scans. The authors advocate for optimized doses to weigh the risks against the benefits adequately.
Despite the lifesaving capabilities of CT scans, the authors warn that the potential harms are often overlooked. They note that since 2007, the volume of CT scans has surged by 35 percent, a rise not fully explained by population growth alone.
Experts in the field concur that judicious use of CT scans is essential. However, they remind us that considerable uncertainty exists in the modeling, as it attempts to estimate absorbed doses in various organs and the associated risk of site-specific cancers. While large studies have explored correlations between CT scans in pediatric and young adult populations and increased risks of blood and brain cancers, adult risk extrapolations are primarily based on studies involving Japanese atomic bomb survivors and individuals exposed to occupational radiation.
Stephen Duffy, an emeritus professor of Cancer Screening at Queen Mary University of London, remarked on the inherent uncertainty of the estimates presented in the study. Duffy advised patients to heed medical recommendations for CT scans, as they provide vital diagnostic information.
In the broader context of a person’s cancer risk, Duffy noted that the numbers indicated by the study are minimal. With just over 100,000 cancers attributed to 93 million scans, this translates into approximately a 0.1 percent increase in the patient’s lifetime cancer risk per CT examination. Given that the lifetime cancer risk for the average American hovers around 40 percent, the additional risk posed by CT scans is relatively small.
Experts Doreen Lau, specializing in cancer biology at Brunel University of London, echoed Duffy’s views. She stated that the findings should not deter patients from undergoing recommended CT scans. The benefits of identifying or ruling out severe health conditions typically outweigh the minimal risks associated with the procedure.
Nevertheless, the upward trend in CT scan utilization in recent years raises concerns regarding the need for more prudent use among healthcare providers. An editorial accompanying the study, authored by Ilana Richman of Yale University and Mitchell Katz of NYC Health and Hospitals, discussed strategies that practitioners can adopt to ensure a balanced risk-benefit analysis before proceeding with CT scans. They highlighted the importance of incorporating diagnostic algorithms and considering alternative imaging options, such as ultrasounds and magnetic resonance imaging (MRIs).
The authors of the editorial concluded that addressing this complex issue will require more than simple solutions. They assert that educating clinicians about avoiding low-value testing and involving patients in decisions regarding CT scans where alternatives exist may help foster a culture of careful practice in medicine.
In summary, as the frequency of CT scans continues to rise, the medical community is urged to balance their potentially lifesaving benefits with the associated risks, ensuring that patient safety remains a top priority.
image source from：https://arstechnica.com/health/2025/04/ct-scans-could-cause-5-of-cancers-study-finds-experts-note-uncertainty/
