Comparing DBT+s2D performance with FFDM for breast cancer screening
The first randomized clinical trial to determine if digital breast tomosynthesis (DBT) plus synthesized, two-dimensional (s2D) mammography is superior to full-field digital mammography (FFDM) for early breast cancer detection in a systematic population-based screening program has been launched in Germany. Multiple institutions will recruit 80,000 women to rapidly reach enrollment requirements, and equipment from multiple vendors will be utilized.
The advantage of s2D is that images are reconstructed without any additional radiation exposure directly from DBT data sets. When 2D digital mammography and DBT are combined, there is a substantial improvement in diagnostic accuracy, but radiation dose exposure is nearly doubled.
Principal investigator Walter Heindel, MD, professor of radiology and director of the Institute for Clinical Radiology at the University of Münster, says that data are scarce regarding the diagnostic performance of a single use of DBT+s2D. The two-arm parallel, randomized, controlled trial has two primary objectives. The first is to evaluate whether DBT+s2D can increase the detection rate of invasive breast cancers during a screening exam at least 33% more than standard 2D-FFDM. The second is to compare the cumulative incidence of interval cancers in order to assess the prognostic importance of additional cancers diagnosed by DBT+s2D and to investigate the potential for over-diagnosis. Secondary endpoints are the detection rate of ductal carcinoma in situ and of tumor size T1, the recall rate for assessment, the positive predictive value (PPV) of recall, and the cumulative 12-month incidence of interval cancers.
If DBT+s2D increases invasive cancer detection, without increasing the number of false-positive recalls, and decreasing interval cancers by up to 30%, the researchers say DBT+s2D “carries the potential of challenging the current standard screening modality.”
Recruitment by multiple imaging centers in North Rhine-Westphalia and Lower Saxony is expected to accelerate enrollment. An interim analysis is planned when data about the detection rate of invasive breast cancer of 40,000 patients is available, which the researchers expect to occur within the next year. The study is estimated to be completed in June 2023.
Several clinical trials evaluating DBT+s2D are underway in Italy, Norway, and the U. S. The researchers hope their data will expand the findings of these trials, which are estimated to end in December 2018, January 2020, and 2030 respectively.
- Weigel S, Gerss J, Hense H-W. Digital breast tomosynthesis plus synthesised images versus standard full-field digital mammography in population-based screening (TOSYMA): protocol of a randomised controlled trial. BMJ Open. 2018 8;5: e020475. doi: 10.1136/bmjopen-2017-020475.