Digital breast tomosynthesis (DBT) is more effective than digital 2D mammography for detecting invasive breast cancer, according to research published in The Lancet Oncology.

In the TOSYMA trial, researchers compared DBT plus synthesized 2D mammograms (DBT-s2D) with standard 2D full-field digital mammography (2D-FFDM) and found a significantly higher rate of invasive breast cancer detection with DBT-s2D.

The trial ( identifier NCT03377036) enrolled more than 99,000 women aged 50 to 69 years. The patients were randomly assigned to DBT-s2D (n=49,804) or 2D-FFDM (n=49,830) between July 5, 2018, and December 30, 2020.

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The rate of detection for invasive breast cancer was 7.1 cases per 1000 women screened in the DBT-s2D group and 4.8 cases per 1000 women in the 2D-FFDM group (odds ratio [OR], 1.48; 95% CI, 1.25-1.75; P <.0001).

The detection rate for invasive breast tumors up to 20 mm in diameter was higher with DBT-s2D than with 2D-FFDM (OR, 1.73; 95% CI, 1.41-2.13). However, the detection rate for ductal carcinoma in situ did not differ significantly between the 2 groups (OR, 0.94; 95% CI, 0.65-1.35).  

No serious adverse events were reported, and device deficiencies were rare. Patients in the 2 groups were similarly likely to be recalled for further assessment.

The researchers noted that TOSYMA is the first randomized controlled trial to compare DBT-s2D with 2D-FFDM in a multicenter and multivendor setting. The trial results “might help to close an important knowledge gap and to develop advanced strategies for an improved systematic early breast cancer detection in population-based settings,” the team wrote.

The researchers did note that the study is limited because analyses were based on only 1 round of screening, and mammography was performed according to the technical standards of 2018.

“The study design with extended follow-up (TOSYMA-2) will provide further insights about the prognostic implications of increased detection of invasive breast cancer at screening by determination of interval breast cancer incidence at 24 months in both groups,” the researchers wrote.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Heindel W, Weigel S, Gerß J, et al. Digital breast tomosynthesis plus synthesised mammography versus digital screening mammography for the detection of invasive breast cancer (TOSYMA): A multicentre, open-label, randomised, controlled, superiority trial. Lancet Oncol. 2022;S1470-2045(22)00194-2. doi:10.1016/S1470-2045(22)00194-2