3D breast tomo again outperforms traditional 2D in reducing recall rates

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 - Breast Tomo
Screening patient whose cancer in her right breast was not seen on standard 2D mammography (left) but was identified by tomosynthesis (right).”
Source: Emily Conant, MD

Another study has found reduced recall rates, along with increased cancer detection, for patients who undergo 3D digital breast tomosynthesis (DBT) rather than standard 2D mammography at screening.

The authors of the large study, conducted at Beth Israel Deaconess Medical Center in Boston, position their work alongside previous similar investigations, citing several that have suggested DBT may reduce the screening recall rate, reduce the false-positive rate and, possibly, increase the cancer detection rate.

Richard E. Sharpe, Jr, MD, and colleagues combined a prospective study with a retrospective component to look at 85,852 asymptomatic women screened for breast cancer over a three-year period beginning in 2011. (Sharpe is now with Kaiser Permanente in Denver.)

They introduced a DBT unit into their existing 2D mammography screening program, assigning participating patients to the first available machine and sending most exams (90 percent) to 10 breast-subspecialized radiologists for interpretation.  

The study team analyzed 80,149 (93.4 percent) 2D exams and 5,703 (6.6 percent) “tomo” exams and found:

  • DBT detected 54.3 percent more carcinomas (+1.9 per 1000) than 2D mammography.
  • The recall rate was 7.51 percent for 2D mammography and 6.10 percent for DBT (absolute change, 1.41 percent; relative change, –18.8 percent).
  • The DBT subgroup demonstrated a significantly lower recall rate for patients with extremely or heterogeneously dense breasts and for patients in their 40s or 60s (but not in their 50s).

Noting the anomalous age finding, the authors pointed out that patients in all age groups experienced a reduction in the recall rate after DBT.

“However, there is limited biologic explanation, to our knowledge, as to why patients in the sixth decade would not have a similar benefit” to that seen in women in their fifth and seventh decades.

Digital breast tomosynthesis “appears to represent a significant improvement over traditional 2D screening mammography, as it results in fewer recalls from screening and can be used to detect more breast cancers,” the authors conclude. “Further cost-benefit and outcomes research is indicated to enable us to better understand the results of implementation of a DBT screening option.”  

The study was posted ahead of print in Radiology. Read it here.