Mammograms have advanced along with the changing technology landscape, with digital mammograms all but replacing film-based screening. Many women are now wondering whether tomosynthesis, also known as a three-dimensional (3-D) mammogram, is the best choice for breast cancer screening.
The 3-D mammogram procedure resembles the conventional mammogram to which women are accustomed, with two exceptions:
1. 3-D mammograms offer less breast compression when used independently.
2. The equipment moves around the breast, taking images from multiple angles as it moves, instead of remaining stationary.
Whereas digital mammograms provide just two views of the breast as a whole—top to bottom and side to side—3-D mammograms take multiple images, which a computer assembles to create detailed 3-D slices. These one-millimeter slices enable doctors to minimize the problems of dense breast tissue and overlapping tissue caused by breast compression and examine questionable areas without the need for more tests or biopsies.
The result is a clearer set of images that can be examined one layer at a time, which may improve cancer detection rates and decrease the number of women called back for more testing.
Recent studies have shown that 3-D mammograms, approved by the U.S. Food and Drug Administration in 2011, are likely to outperform digital mammograms in finding small invasive and lobular cancers—those most likely to be fatal. An analysis of more than 450,000 screening exams, published in June 2014 by the Journal of the American Medical Association, concluded that tomosynthesis combined with digital mammography was associated with a larger decrease in recall rate and an increased cancer detection rate when compared with digital mammography alone.
Given the option between digital and 3-D mammograms, most experts say the choice is unclear, as 3-D mammograms haven’t yet been definitively proved to provide additional clinical benefit; more research is needed to compare the technologies among randomly selected patients. And not all insurers cover 3-D imaging, so the screening may require additional out-of-pocket costs.
Our advice: Women with dense breasts are currently the most likely to benefit from 3-D mammograms, although all women may benefit from improved detection and reduced need for follow-up testing.