Where it is offered in the state, 3D mammography, also known as Digital Breast Tomosynthesis (DBT), is credited with an increase in cancer detection rates and a decrease in recall rates. The lower recall rates with the new technology may decrease the stress and anxiety that women experience when called back after a 2D mammogram is inconclusive.
“At the University of Arkansas for Medical Sciences (UAMS), we offer 3D mammography to all patients who can participate for the exam,” said Gwendolyn Bryant-Smith, MD, chief of breast imaging and an assistant professor in the UAMS Department of Radiology. “Patients have to be able to hold their breath sufficiently for the exam. DBT was approved by the FDA in 2011. UAMS has had DBT since 2014.”
Bryant-Smith said numerous studies comparing 3D and 2D digital mammography combined as opposed to 2D digital mammography alone have seen an increase in invasive breast cancer detection combined with a decrease in having to call patients back for more views. It also decreases interval breast cancers, cancers that occur within 12 months of a normal mammogram.
“DBT is especially helpful in patients with dense breast tissue because it reduces breast tissue overlap,” Bryant-Smith said. “This helps with a decrease in false positives and false negatives. By decreasing the overlap of breast tissue, you are more likely to determine if a finding is real or summation of normal tissues. At our facility, we prefer DBT. Dense breast tissue is the enemy of regular 2D mammography. Dense tissues are white; so is cancer. DBT is not perfect, but it is improved imaging especially for patents with dense breast tissue. It can also be helpful in patients with fatty breast tissue.”
A 2014 article in the Journal of the American Medical Association (JAMA) evaluated 454,850 mammogram exams, and showed 107/1,000 cases were called back with 2D digital mammography alone compared to 91/1,000 cases called back with 2D combined with DBT. Cancer detection was 4.2/1000 with digital alone compared to cancer detection of 5.4/1,000 with 2D combined with DBT. That resulted in 1.2/1,000 more cases of invasive breast cancer detection.
“There are some slight drawbacks,” Bryant-Smith said. “No test is perfect. Initially when you transition to 3D, there is a learning curve. It takes longer to read test results. With typical 2D, you will review approximately 4-8 images depending on the patient. With 3D mammography, because of different angles and reconstruction, there are hundreds of images to review which increases the interpretation time for the radiologist.”
It also increases the radiation dose. A study published in 2015 showed there is about two times more radiation with combined 2D and 3D. But it is now possible to make a synthetic 2D view reconstructed from the DBT images. “That reduces the radiation by half,” Bryant-Smith said.
A study in 2010 published in Radiology by Hendrick concluded that a single 2D mammogram increases the lifetime risk of fatal breast cancer from 1.3 to 1.7 in 100,000 women aged 40 years of exposure. It is less than one case in one million for women aged 80 years at exposure.
“The point is, it is a very small risk,” Bryant-Smith said. “A mammogram is a small risk compared to saving lives by finding cancer when it is small and can be most effectively treated.”
William Landrum, MD, radiologist, Baxter Regional Medical Center, Mountain Home, said 3D is not a lot more expensive, and it is worth it.
“I would not have my wife have anything other than a mammography with tomosynthesis,” Landrum said. “It is just so much better and more accurate. It is worth the small increase in cost just in terms of overall patient care. It improves the specificity and sensitivity of mammography, and is particularly useful in younger women or women with dense breast tissue—which is a bit of issue with the whole mammography business. It reduces the number of ladies we have to call back for additional mammographic workup.”
Landrum said from the radiologist’s standpoint, it adds a lot of confidence to readings because they can see the breast tissue so much better. With 2D studies, you can have questions about what is going on in a certain area.
“Tomosynthesis can almost always tell you what is going on either benign or something suspicious,” Landrum said. “When both 2D and 3D fail to be conclusive, a woman may have to come back for an ultrasound or an additional mammography view. But the call back rate is much less.”
At Baxter Regional, they do both 2D and 3D at the same time while the breast tissue is compressed. It adds about four to five seconds to each of four views.
“If you read the literature, it is becoming more the standard of care,” Landrum said. “We looked very heavily into tomosynthesis and decided we can’t have part of our patients have conventional 2D and no tomosynthesis. We felt it was important for all patients to have the advantages of tomosynthesis. We are 100 percent tomosynthesis. We even have a mobile van that is tomosynthesis. We provide mammography services to the surrounding area and it is tomosynthesis, just like the studies acquired at the hospital.”
Landrum said they are small enough that they could go 100 percent tomosynthesis easily.
“With a larger hospital, the financial impact of going 100 percent tomosynthesis would be fairly large,” Landrum said. “Over time as older 2d units are replaced, I think the tomosynthesis units will be purchased.”
Cooper Clinic in Fort Smith recently added DBT. In addition to saving lives, early detection may eliminate the need for radical surgery, said Cooper Clinic Medical Director Rebecca Fleck, MD.
“There’s a lot of anxiety that comes with a suspicious mammogram,” Fleck said. “Is it a false positive? If it is cancer, could it have been detected earlier?”
Fleck said 3D mammograms are more likely to get it right the first time.
“The physicians of Cooper Clinic consider this technology as the gold standard for breast care, and we are very pleased to offer our patients the early detection and peace of mind that 3D exams can provide,” she said.
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