CT scan exposing more Americans to cancer; study links it with 100,000 new cancers across the US

Computed tomography, better known as a CT scan, has become one of those medical tests that doctors rely on all the time—and for good reason. It’s fast, detailed, and helps catch problems that other scans might miss. Over the years, technology has made CT scans even sharper and more useful, which explains why hospitals and clinics are using them more than ever. In fact, in the US, the number of CT scans being done has climbed back up after the pandemic slowdown and is now higher than before. Simply put, CT has moved from being “special” to almost essential.

JAMA study highlights the life threatening risk associated with annual computed tomography (CT) examinations in the United States
A recent study has found that the widespread use of CT scans in the United States could be linked to about 103,000 new cancer cases over the lifetime of those exposed in 2023 alone. With 93 million CT scans performed that year, researchers estimate that radiation from these scans could account for roughly 5% of all new cancer diagnoses annually if current practices continue. The study highlights that while CT scans are an essential diagnostic tool saving countless lives, their radiation exposure is a known cancer risk, especially concerning children, who are more sensitive to radiation.

How did researchers estimate the 103,000 future cancers?
Researchers estimated the projected 103,000 future cancers from the 2023 CT scans by combining several key data points and methods:

Number of CT scans: They used data showing that approximately 93 million CT scans were performed in the US in 2023.

Radiation dose per scan: Each type of CT scan involves a measurable radiation dose, which is known from medical physics and radiology studies.

Risk models: Researchers applied well-established cancer risk models, primarily based on data from atomic bomb survivors and other radiation-exposed populations. These models estimate the lifetime risk of developing cancer per unit of radiation exposure.

Demographic factors: The risk assessment accounted for age, sex, and the specific organs exposed during the CT scan, recognizing that younger patients have higher sensitivity to radiation-induced cancer.

Lifetime risk projection: By multiplying the radiation dose from each scan by the associated cancer risk and the number of scans performed, then summing across all scan types and patient demographics, researchers estimated the total number of future cancer cases attributable to 2023 examinations.

Adjustments for uncertainty: Researchers included statistical uncertainty ranges and sensitivity analyses to reflect confidence intervals in their estimates.

This approach integrates real-world CT scan usage data with recognized radiation risk science to provide a credible projection of the potential long-term cancer burden from medical CT imaging.

The most common cancers projected to result from CT radiation include lung, colon, leukemia, bladder, and breast cancers. Abdominal and pelvic CT scans contribute to the largest share of these cancer cases. The risk per scan is higher in children but, since adults undergo the majority of scans, most projected cancers occur in adults.

Experts emphasize that for individual patients, the risk from a necessary CT scan is low and the benefits usually outweigh the risks. However, the growing use of CT imaging, sometimes in situations without clear clinical need, raises concerns.

How should one weigh CT scan benefits versus radiation risk?
Weighing the benefits of a CT scan against the radiation risk depends on your specific health situation, and it’s important to discuss this with your healthcare provider. Here’s a simple way to approach it:

Medical necessity: If your doctor recommends a CT scan, it’s usually because the potential benefits, accurate diagnosis, guiding treatment, or detecting serious conditions, outweigh the small risk of radiation. Often, CT scans provide critical information that other tests cannot.

Risk factors: Consider your age, overall health, and frequency of past scans. Younger people and children are more sensitive to radiation. If you’ve had multiple CT scans recently, it’s worth discussing whether this scan is essential.

Alternatives: Ask if there are non-radiation imaging options like MRI or ultrasound that could provide similar information. Sometimes these are suitable alternatives with no radiation exposure.

Radiation dose: Inquire about the radiation dose for your particular CT scan. Advances in technology have reduced doses significantly, and radiologists strive to use the lowest dose needed for clear images.

Communication: Be open with your doctor about your concerns. Together, you can evaluate the urgency of the scan, potential health consequences of skipping it, and personal risk factors.

In most cases, if a CT scan is recommended by a qualified provider, the benefit of accurate diagnosis and treatment outweighs the risk. But it’s always good to have a clear, informed discussion tailored to your health needs.

This study calls attention to balancing CT scan benefits with their potential long-term cancer risks, urging more cautious and judicious use of this powerful imaging technology in US healthcare. "If current practices persist, CT-associated cancer could eventually account for 5% of all new cancer diagnoses annually," the researchers have warned.