CT Scans and Cancer: 2025 Study’s Must-Know Risks

Introduction to CT Scans and Cancer

Computed Tomography (CT) scans are vital for diagnosing cancer, injuries, and chronic diseases. However, a 2025 study in JAMA Internal Medicine highlights significant CT scans and cancer risks, projecting 103,000 future cancers from 93 million scans performed in 2023 [1]. This post explores the study’s findings, high-risk groups, and actionable steps to minimize risks, led by Dr. Rebecca Smith-Bindman at the University of California, San Francisco [2].

Key Findings from the 2025 Study

The study, published in JAMA Internal Medicine [1], used data from the UCSF International CT Dose Registry (2018–2020) to estimate lifetime cancer risks from CT scans in 2023. Here’s what it found:

Scale of CT Use and Cancer Projections

• 93 million CT scans were performed Onderon 61.5 million patients in 2023.
• These scans are projected to cause 103,000 cancers (90% uncertainty range: 80,000–127,000).
• CT scans could account for 5% of annual cancer diagnoses (1.95 million in 2023), comparable to alcohol (5.4%) or obesity (7.6%) [3].

High-Risk Groups

• Children under 1 face the highest risk per scan (20 cancers per 1,000 exams for girls).
• Adults aged 50–59 have the most cancers (10,400 in females, 9,300 in males) due to higher scan volume.
• Women face elevated risks for lung (70% of 22,400 cases) and breast cancer (5,700 cases).

Common Cancers

The study identifies the most frequent CT-related cancers:

• Lung cancer: 22,400 cases (90% UL: 20,200–25,000).
• Colon cancer: 8,700 cases (90% UL: 7,800–9,700).
• Leukemia: 7,900 cases (90% UL: 6,700–9,500).
• Breast cancer (in women): 5,700 cases (90% UL: 5,000–6,500).

High-Risk Scans

• Abdomen and pelvis CTs cause 37% of cancers (37,500 cases), driven by frequent use (32% of scans) and multiphase scanning.
• Chest CTs contribute 21% of cancers (21,500 cases).
• Single-phase scanning, using one image set, reduces radiation compared to multiphase scans (used in 28.5% of exams) without losing diagnostic accuracy [4].

Why CT Scans and Cancer Risks Are Rising

CT use has surged 30% since 2007, from 68.7 million to 93 million scans, partly due to low-value imaging and population aging [5]. Dr. Smith-Bindman notes, “CT scans are vital, but rising use, often without clear need, increases cancer risks” [6]. Multiphase scans and improved dosimetry methods explain the 3–4 times higher cancer projections compared to 2009 (29,000 cancers).

Reducing CT Scans and Cancer Risks

To mitigate risks while preserving CT’s benefits, consider these steps:

For Oncologists

• Justify scans: Follow guidelines (e.g., for pulmonary embolism or pediatric trauma) to avoid unnecessary imaging.
• Optimize doses: Use single-phase scans when possible to lower radiation exposure.
• Tailor protocols: Account for patient age and sex, especially for children and women (higher lung/breast cancer risks).

For Patients

• Ask questions: Will this scan change my treatment? Can a lower-dose scan be used?
• Request single-phase scans: These reduce radiation without compromising accuracy in many cases.
• Discuss risks: Understand the small but real cancer risk (1 in 1,000 per scan) and weigh it against benefits.

Uncertainty and Context

The study’s estimates range from 80,000 to 127,000 cancers due to variations in dose and usage assumptions. Conservative assumptions (e.g., excluding CT-guided procedures) may underestimate risks. If CT use and doses remain unchanged, CT-related cancers could rival major risk factors, making dose optimization critical.

Call to Action

CT scans save lives but carry risks that demand attention. Oncologists should adhere to guidelines and optimize protocols, while patients should engage in informed discussions. For more insights, watch our video on CT scan risks [7] or explore related cancer research on OncologyTube.com [8].

References:

1. JAMA Internal Medicine Study
2. UCSF Department of Epidemiology and Biostatistics
3. American Cancer Society: Cancer Risk Factors
4. UCSF CT Dose Registry
5. IMV Medical Information Division
6. Interview with Dr. Smith-Bindman
7. OncologyTube CT Scan Video
8. OncologyTube Cancer Research

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