Evidence Shows 3D Mammography Improves Cancer Detection Rates

3D Mammography improves cancer detection and reduces false-positive results, a finding that could change the breast cancer screening protocol for women.

Digital breast tomosynthesis, or 3D mammography, was superior to traditional digital mammogram alone in identifying invasive cancers and that use of this 3D technology resulted in significantly fewer call-backs for additional imaging, according to new research published today in JAMA. 

Pertinent Points

The addition of
3D mammography
to traditional digital mammo screenings resulted in a:

- 41% increase in detecting invasive cancers.

- 15% decrease in unnecessary recalls for false-positives.

- 29% increase in detecting all breast cancers.

"It's the most exciting improvement to mammography that I have seen in my career, even more important for women than the conversion from film-screen mammography to digital mammography," said senior author Emily F. Conant, MD, chief of breast imaging, department of radiology, Perelman School of Medicine at the University of Pennsylvania. "3D Mammography finds more clinically significant breast cancers earlier, which is the key so that women have more treatment options and ultimately better health outcomes."

The retrospective study looked at 281,187 digital mammography examinations and 173,663 examinations with both tomosynthesis and digital mammography between 2010 and 2012. All tomosynthesis was performed using Selenia Dimensions digital breast tomosynthesis system, manufactured by Hologic, Inc, which is the only FDA-approved product for 3D mammography.

The analysis showed that the addition of tomosynthesis to digital mammography was associated with a 41% increase in detection rates for invasive cancers compared with digital mammography alone. The average detection rate was 2.9 per 1,000 screens for digital mammography versus 4.1 per 1,000 screens with digital plus 3D mammography.

The overall cancer detection also was improved, from 4.2 per 1,000 screens with digital mammography to 5.4 per 1,000 screens with the addition of 3D mammography. Also, 3D mammography lowered the rate of false-positive results by 15%, reducing the number of clinically unnecessary biopsies and the recall rate for additional testing. Finally, adding 3D mammography increased the positive predictive value for recall from 4.3% to 6.4% and for biopsy from 24.2% to 29.2%.

Most insurance companies currently don’t cover breast tomosynthesis, and out-of-pocket costs for patients to “upgrade” to 3D mammography typically range from $40 to $100.

“We believe this study is groundbreaking because of the sheer number of mammograms we reviewed, “says Sarah Friedewald, MD, lead author of the study and co-medical director of the Caldwell Breast Center at Advocate Lutheran General Hospital, Park Ridge, Illinois. “Because it is ten times larger than other studies to date, and because the data came from both academic and community health care settings,  we think it tells a compelling story about the effectiveness of 3D mammography.”

Women will see little difference in the 3D mammography exam.  It takes just a few seconds longer than traditional 2D mammography.  However, the radiologists reading the exams will see through the layers of the breast and diagnose potential problems more quickly.

The study did not assess for a clinical outcomes benefit, and the authors noted that a longer-term study is needed.

“The success of mammography screening in reducing mortality is predicated on the principle of detecting and treating small, asymptomatic cancers before they have metastasized. Accordingly, the preferential increase in invasive cancer detection with addition of tomosynthesis may be of particular value in optimizing patient outcomes from mammography screening,” the authors wrote.