Adding tomosynthesis improved mammography’s cancer detection

Adding tomosynthesis to screening digital mammography decreases the "recall" rate by 15% while increasing the cancer detection rate by 29%, according to a report published online June 25 in JAMA.

Researchers compared the performance of screening digital mammography alone (281,187 cases) against the performance after tomosynthesis was added to mammography (173,663 cases) at 13 sites in geographically diverse regions across the country. The work was funded primarily by Hologic, maker of the only Food and Drug Administration–approved tomosynthesis equipment at the time of this retrospective study, said Dr. Sarah M. Friedewald of the Caldwell Breast Center, Advocate Lutheran General Hospital, Park Ridge, Ill., and her associates.

Dr. Sarah Friedewald

The "recall" rate – the proportion of patients requiring additional imaging based on the results of their screening mammography – declined from 107 per 1,000 screens with digital mammography alone to 91 per 1,000 screens when tomosynthesis was added, a relative reduction of 15%. At the same time, the cancer detection rate rose from 4.2 to 5.4 per 1,000 scans, a relative increase of 29%. After tomosynthesis was introduced, the detection rate of invasive cancers rose from 2.9 to 4.1 per 1,000 scans, while that of ductal carcinoma in situ remained unchanged at 1.4 per 1,000, the investigators said (JAMA 2014 June 25 [doi:10.1001/jama.2014.6095]).

It is important to note that this study did not assess clinical outcomes, so it remains to be seen whether these improvements in screening mammography translate into clinically relevant improvements in breast cancer mortality. In addition, this study was limited in that it was retrospective and nonrandomized, they wrote.

This study was funded by tomosynthesis equipment maker Hologic and the National Cancer Institute. Dr. Friedewald and her associates also reported other ties to Hologic.