3D versus 2D mammograms


Today, I want to briefly discuss the use of tomosynthesis (sometimes called 3D mammography) for breast cancer screening. This sophisticated imaging approach uses a moving X-ray source to acquire 3-Dl volume data than can be displayed as thin slices. While relatively new, tomosynthesis is becoming more popular, especially for evaluating women with dense breasts (as defined by mammograms), and for women at high risk for getting breast cancer. Still, we have fairly limited data on outcomes when tomosynthesis is used for routine screening.

The results of a manufacturer-sponsored study were recently reported. The investigation looked at Italian women at least 48 years old, and did screening with integrated 2D and 3D mammograms.Screening mammograms were then interpreted by radiologists, first using standard 2D images and subsequently using integrated 2D/ 3D mammography.

Among over 7000 women screened, 52 invasive cancers and 7 cases of ductal carcinoma in situ were detected. The rate of cancers detected per 1000 screens was 5.3 with 2D technology and 8.1 with integrated 2D plus 3D screening, a statistically significant increase in sensitivity. Of 395 false-positive screens (that is, the test suggested cancer, when there actually was none), 181 resulted from both screens, 141 resulted from 2D only, and 73 resulted from integrated screens.

Bottom line: The finding that integrated screening enhances sensitivity (th ability to find cancer) while reducing false-positive results (the test says there is cancer, when there is not) match results from an interim analysis of a Scandinavian trial.

Any downsides? 2D/3D screening roughly doubles the radiation exposure to the breast.

Going forward: We need more randomized trials comparing 2D with integrated 2D/3D screening mammograms. In my own institution, we prefer the tomosynthesis approach. I’m Dr. Michael Hunter.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. And have a great day!

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Harvard AB Yale MD UPenn Radiation Oncology Radiation Oncologist, Seattle area

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