CT Scans and Cancer Risk: Key Facts You Should Know

A recent study has raised concerns about the excessive use of CT (computed tomography) scans, linking them to approximately 5% of all new cancer diagnoses annually. Since 2007, the use of CT scans in the United States has grown by 30%.

Researchers at the University of California, San Francisco (UCSF) employed statistical modeling to estimate how many cancer cases may develop from the 93 million CT scans performed. The model projects that over 100,000 of those could eventually result in cancer due to radiation exposure from the scans.

Dr. Rebecca Smith-Bindman, lead author of the study and professor at UCSF, emphasized that this risk is often overlooked. “Given how frequently CTs are used in the U.S., many future cancers could result if current practices don’t change,” she said. “CT scans pose a risk comparable to known contributors like alcohol and obesity. Reducing scan frequency and minimizing radiation per scan could save lives.”

Balancing Risks and Benefits

Despite these findings, experts stress that the benefits of CT scans typically outweigh the risks. Professor Stephen Duffy from Queen Mary University of London explained, “The estimated risk is an increase of just 0.1% in a patient’s lifetime cancer risk per CT scan. Considering the baseline lifetime cancer risk is around 50%, this added risk is relatively small.”

The study estimates how many future cancer cases might arise from CT scan radiation exposure in 2023. Although CT imaging involves ionizing radiation—known in large doses to increase cancer risk—the researchers are not claiming direct causation. Instead, the study points to a potential issue of overuse.

A Wake-Up Call for Smarter Use

This is a well-executed modeling study using reliable data from U.S. hospitals, said Doreen Lau, a lecturer at Brunel University London. She wasn’t involved in the research but emphasized the importance of using CT scans judiciously, especially in younger patients or in cases where alternative imaging like MRI or ultrasound might suffice.

Lau added, The study isn’t saying people should avoid CTs altogether—if a doctor recommends one, it’s likely necessary. But it highlights the need to minimize unnecessary imaging and use the lowest possible radiation dose.

U.S. vs. U.K.: Different Approaches

The study also highlights how other countries regulate CT scans more strictly than the U.S. For instance, in the U.K., authorities enforce strict guidelines on medical use of ionizing radiation through principles like ALARA (As Low As Reasonably Achievable), which require healthcare professionals to minimize exposure whenever possible.

Dr. Giles Roditi of the University of Glasgow said that professionals in the U.K. review every imaging request and can challenge it when necessary.“In contrast, in the U.S., doctors often issue scan orders that radiology departments must follow, partly due to financial incentives tied to imaging fees.

He also noted the issue of duplicated scans in the fragmented U.S. healthcare system, where it may be simpler or more profitable to redo a scan than to retrieve existing images.

Promoting Safe and Informed Imaging

Experts agree that reducing unnecessary CT scans is key—but not at the cost of discouraging necessary diagnostic procedures. Lynda Johnson from the U.K.’s Society and College of Radiographers said that highly trained professionals carry out CT scans and ensure they are properly justified and optimized.

She stressed the importance of clear communication around both the benefits and risks of CT imaging. “Focusing only on risk can mislead patients and cause them to avoid scans that could lead to early diagnosis and effective treatment,” she said. “Patients need accurate, personalized information to make informed choices about their care.

Professor Richard Wakeford from the University of Manchester emphasized that healthcare professionals should consider the risks of exposure to low doses of radiation in clinical decisions, but they should not let broad and uncertain projections of cancer cases overly influence that judgment.

Read the original article on: New Atlas

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