According to a new study, digital breast tomosynthesis, or 3D mammography, can improve the detection of breast cancer, according to a new study.
“We can detect cancers that are otherwise hidden and not visible with 2D mammography,” explained Per Skaane, MD from Oslo University Hospital in Norway.He presented results from the Oslo Tomosynthesis Screening Trial at the Radiological Society of North America 100th Annual Meeting.The trial was part of the Norwegian Breast Cancer Screening Program, and was conducted from November 2010 to December 2012, It is the largest prospective trial to compare 2D with 3D mammography for breast cancer screening, and involved 25,547 women.3D mammography uses the same equipment as 2D mammography, except the x-ray tube moves in an arc across the breast. Software then reconstructs the image.
In their analysis, Dr. Skaane and his colleagues focused on the ability of 3D mammography to detect cancer in dense breasts. Historically, dense breast tissue is more difficult to examine and appears white in exams. There are four categories of breast density. Only about 10% of women have category 1, or low-density breasts, which meant that the majority of women risk having a suboptimal screen with the conventional 2D mammography.
“For those of us who have used 3D mammography, it is very hard to look back at 2D,” said Debra Copit, MD, from Albert Einstein Medical Center in Philadelphia.
Dr. Skaane described the 3D system as a good breast screening upgrade because it leverages existing equipment, manpower, and programs.Although there has yet to be comparison studies of the different 3D mammography systems, he suggested that 3D mammography is the wave of the future.
“3D mammograms have been found to correctly identify cancers 4-5% more often than regular 2D digital of film mammograms. Just as importantly, women who undergo screening with 3D mammography are 15% less likey to be called back for more testing due to a suspicious finding that turns out not to be cancer. This is called the “non-cancerous recall rate,” which when lower means fewer false scares.”
Experts reported in the Journal of the American Medical Association, that 3D technology can boost the accuracy of mammography screening.
“This is very positive,” said Dr. Etta Pisano of the Medical University of South Carolina in Charleston, who wrote an editorial published with the study.
“If you have access to [3D mammography], you should feel comfortable getting it,” Pisano said.
However, long-term results are still being studied, “We would like to see long-term outcomes,” said Dr. Sarah Friedwald, the lead researcher on the new study and a radiologist at Advocate Lutheran General Hospital in Park Ridge, IL. Friedwald also noted shorter-term advantages, “We found 3D mammography really does help doctors find more invasive breast cancers while cutting down on callbacks,” she said.
Friedwald’s team looked at nearly 455,000 screening mammograms done at 13 hospitals that all switched from digital mammography to digital-plus-3D after the 2011 FDA approval. In the year before switching, the hospitals found 1.4 cases of DCIS per 1,000 screenings, and that remained unchanged after the switch. Instead, detection of more-advanced, “invasive” cancers went up 41 percent.
Although not all the answers to mammographic exams have been discovered, research may lead to more tailored recommendations for different groups of women, Pisano remarked.