- Researchers say digital breast tomosynthesis, a 3D imaging technology, is more accurate at detecting breast cancer than digital 2D techniques.
- They add that the 3D technology also produces fewer false positive results.
- Experts say the 3D screenings are more expensive, but they are being used more often in medical facilities.
There is new evidence that a more advanced screening technology may be better at detecting breast cancer.
A study published today in the journal Radiology reports that digital breast tomosynthesis (DBT), a 3D imaging technique, produced better screening outcomes than standard digital mammography.
If that sounds somewhat familiar… that’s because it is.
However, the study’s lead author says what sets this research apart is that it looked at a large and diverse population of women.
“The findings reinforce what we’ve seen before, but it’s powerful because of the size,” said Dr. Emily Conant, a professor of radiology and the division chief of Breast Imaging at the Hospital of the University of Pennsylvania.
“It’s not just from one site or a few sites. It’s really across the country,” she told Healthline.
Details from the breast cancer screening study
Conant and her colleagues compiled data from five large healthcare systems around in the United States.
The group they studied was made up of more than 1 million women ages 40 to 79.
The women were screened with either DBT or 2D digital mammography alone between January 2014 and December 2020.
Most of the women had at least two screenings. That meant the researchers looked at more than 2 million exams.
The cancer detection rate for participants screened with DBT was 5.3 per 1,000 screened versus 4.5 per 1,000 for those screened with 2D digital mammography only.
Besides the higher cancer detection rate, the researchers said they found fewer recalls and fewer false positives with the DBT technology. In the participants who were recalled, there was a higher rate of detection of cancers.
“Are we more accurate and more specific in our recalls? Have fewer false positives? Yes. With [DBT] are we finding more cancers? Yes,” Conant said. “And then when we recommend a biopsy based on one of the recalls, in asymptomatic women, are we finding more cancers per recall? Yes.“
“Part of the controversy over screening is because of false positives. It’s because of women being called back for benign things, even biopsied for benign things,” Conant explained. “This is a very cost effective way to find cancers early before they become symptomatic.”
Dense breast tissue
Scientists say DBT is more effective because it is able to capture multiple images of the breast from different angles.
That’s especially important for women with dense breast tissue.
“The X-ray tube moves across an arc and takes multiple quick pictures while you’re being compressed,” Conant explained. “Then those multiple compressions are reconstructed into what I see as slices through the breast… so I can scroll through your breast.”
“If I saw a dense splotch in your right breast, if it was just a 2D mammogram, I wouldn’t know if maybe there was something there that made it denser” she said. “But [with DBT] if I can scroll through it and I see from the inner surface of your breast to the outer surface that this is normal breast tissue, then that three dimensionality helps me determine that you really don’t need extra pictures.”
The Food and Drug Administration (FDA) estimates that about half of women over the age of 40 in the United States have dense breast tissue.
This can make breast cancers more difficult to detect on a mammogram. Dense breast tissue is also considered a risk for developing breast cancer.
Last week, the FDA updated its mammogram regulations to require facilities to notify women about the density of their breast tissue. The new rule has to be implemented within the next 18 months.
“Today’s action represents the agency’s broader commitment to support innovation to prevent, detect and treat cancer,” said Dr. Hilary Marston, the FDA’s chief medical officer, said in a statement. “We remain committed to advancing efforts to improve the health of women and strengthen the fight against breast cancer.”
Should 3D screening be a standard of care?
Dr. Richard Reitherman, a radiologist and medical director of breast imaging at MemorialCareBreast Center at Orange Coast Medical Center in California says he relies on the 3D screening technology.
“Yes and most centers in the U.S. use DBT because of its superior performance” he told Healthline.
However, he says some patients will still require more screening.
“Ultrasound is recommended for women with extremely dense breast tissue,” Reitherman said. “MRI is the most sensitive test for detecting breast cancer. But generally it is reserved for women who have increased risk factors such as a family history of breast or ovarian cancer.”
Conant says the equipment required to perform the DBT screening can be more expensive, but many of the mammogram units around the country are already capable of performing the DBT screening.
“It’s really becoming the standard of care and that is what I recommend,” said Conant.
“If I wasn’t a breast radiologist but knew a little bit about this, I would definitely seek out a site that had tomosynthesis for screening” she added. “Go to sites that you know will do your study with a tomosynthesis machine, or what some people call a 3-D mammogram.”
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