Breast Cancer Detection Rates Show Improvement with 3D Mammography

Researchers at 13 participating institutions have reported in The Journal of the American Medical Association that use of tomosynthesis, also referred to as 3D mammography, in conjunction with digital mammography screening was associated with an increase in cancer detection rates and decrease in the recall rate for additional imaging. The research was sponsored and funded by Hologic, Inc. of Massachusetts, manufacturer of the Selenia Dimensions 3D System,  which was approved by the FDA in 2011. The device takes many low-dose X-rays at different angles to create a three-dimensional cross-sectional image of the breast. The total radiation dose when tomosynthesis is added is approximately twice the current digital mammography dose but remains well below the limits defined by the FDA.

The study, “Breast Cancer Screening Using Tomosynthesis in Combination with Digital Mammography,” was led by Sarah M. Friedewald, MD of the Caldwell Breast Center, Advocate Lutheran General Hospital in Park Ridge, Illinois. A total of 454,850 examinations (281,187 conventional mammograms compared to 173,663 3D mammography exams) from March 2010 through December 2012 were analyzed in the study. Mammography plays a key role in early breast cancer detection and single-institution studies have shown that adding tomosynthesis to mammography increases cancer detection and reduces false-positive results. The new study analyzed the records from 13 U.S. mammography centers before and after they added tomosynthesis; comparisons were made of the cancer detection rate, how often women had to be called back for more scans to check on suspicious findings, and what proportion of the callbacks and biopsies actually found cancer.

Significantly the study observed use of 3D mammography with digital mammography  resulted in a: (1) 41 percent increase in the detection of invasive breast cancers; (2) 29 percent increase in the detection of all breast cancers; and (3) 15 percent decrease in women recalled for additional imaging. Cancer was detected in 4.2 of every 1,000 scans with digital mammography alone, but in 5.4 when the tomosynthesis was added. The researchers were encouraged by the increase in detection of invasive breast cancers, noting that tomosynthesis was “picking up the ones we want to be picking up.” In addition, the reduction in recalls of women for additional imaging was important to alleviate the associated concerns expressed upon reimaging.

While the studies bode well for other device manufacturers to market the device as a screening method in the United States, further studies are needed to assess the relationship of 3D mammography to clinical outcomes.