Pairing tomosynthesis — 3-D mammography — with 2-D mammography leads to a higher cancer detection rate and less additional testing, according to a study published today in the Journal of the American Medical Association. To date, it's the largest study of its kind.

Researchers at the Advocate Lutheran General Hospital evaluated a total of 454,850 exams from 13 centers — 281,187 digital mammography exams and 173,633 digital mammography plus tomosynthesis exams.

They found that there was a 41 percent increase in the detection of invasive breast cancers, a 29 percent increase in the detection of all breast cancers and a 15 percent decrease in women needing additional imaging.

"We found more invasive breast cancers in women who were imaged with tomosynthesis in combination with digital mammography and it's the invasive cancers that we worry about," Dr. Sarah M. Friedewald, lead author of the study, told DOTmed News.

Even though mammography is the gold-standard for breast cancer screening, it is known to suffer from excessive false-positive results, limited sensitivity and the potential for overdiagnosis. Tomosynthesis became FDA approved in 2011 to be used as an addition to 2-D, but if studies continue to find positive results, it may become a standalone technology.

"We get more information with the 3-D imaging and therefore we can better characterize benign abnormalities that we see on the mammogram when we're screening the patients," said Friedewald. For example, some areas of superimposed breast tissue may appear like a lesion with 2-D mammography, but clinicians can page through the breast with 3-D mammography and reveal that it's just normal breast structures.

Last May, Hologic got FDA approval for C-View 2D imaging software, which uses a computer algorithm that takes the information from the 3-D mammography data set and reconstructs a 2-D image without extra exposure to the patient. Friedewald thinks that the software and others like it will usher 2-D mammo out.

"Tomosynthesis is definitely going to become the standard of care," she said. "The software program that allows us to drop the 2-D image, I suspect, will enable us to image with tomosynthesis and not have to take the standard 2-D picture as well."

She thinks that once people become more comfortable with interpreting 3-D mammograms, there will be a "natural progression" into it becoming the standard. Her hospital is currently using the 2-D reconstructive imaging software, but it was not available when the study was being conducted.

They now know that the population as a whole benefits with the addition of tomosynthesis, but there is still more work to be done. "We didn't look at specific sub-populations and patient characteristics that might tell us who benefits more than others with the 3-D imaging," Friedewald said. "I think that's something that would be interesting and we're planning on investigating."

Additionally, they are looking to conduct a long-term outcome study, but results needed for that will have to build over 20 to 30 years.

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