Tomosynthesis plus digital mammography improves cancer detection, reduces recall rates

Nov 26 2012

By Nikki Withers, medwireNews Reporter

Tomosynthesis imaging may improve breast cancer detection while reducing recall rates at mammographic screening, say researchers.

"Radiologists significantly improved their diagnostic accuracy by reading digital mammography in conjunction with tomosynthesis compared with digital mammography alone," writes the team in Radiology.

The researchers conducted two reader studies to compare radiologists' diagnostic accuracy and recall rates for breast tomosynthesis combined with digital mammography against digital mammography alone.

The first study involved 312 women (48 cancer cases) with images read by 12 radiologists while the second study involved 312 women (51 cancer cases) with images read by 15 radiologists.

Elizabeth Rafferty (Massachusetts General Hospital, Boston, USA) and co-investigators found that, in both studies, the diagnostic accuracy for digital mammography plus tomosynthesis was superior to that of digital mammography alone, as shown by a significant difference in the area under the curve of 7.2% in study one and 6.8% in study two.

Overall, all 27 readers demonstrated significant improvements in their diagnostic accuracy.

Based on the Breast Imaging Reporting and Data System (BI-RADS) classification, average diagnostic sensitivity increased with the addition of tomosynthesis in both reader studies, by 10.7% for study one and 16.0% for study two.

Rafferty and team say that almost all of the gains in diagnostic sensitivity from the combined modality were attributable to the improved detection and characterization of invasive cancers. Specifically, sensitivity for invasive cancers increased by 15% and 22% in studies one and two, respectively, compared with 3% for in situ cancers in both studies.

Finally, the researchers found that recall rates for noncancer cases significantly decreased for all readers with the addition of tomosynthesis (range 6‑67%).

"In conclusion, the addition of tomosynthesis to digital mammography offers the dual benefit of improved diagnostic accuracy and significant reduction in false-positive recall rate thereby avoiding unnecessary additional testing and decreasing attendant anxiety, inconvenience, and cost for women," say Rafferty et al.

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