Tomosynthesis – the method being extensively tested for early breast cancer detection by ToSyMa, the world's largest randomized controlled trial - appears to be convincing across the entire line: Compared to the standard method, the new technology leads to a significantly higher detection rate especially in women with extremely dense breast tissue, which is not only considered a risk factor but also makes diagnostics considerably more difficult. Digital breast tomosynthesis could provide a remedy. The results have now been published in the journal Radiology.

News from ToSyMa: The world’s largest randomized controlled trial for early breast cancer detection can claim a new success – especially for women with extremely dense breast tissue. Such tissue not only represents an independent risk factor of breast cancer development, but also makes diagnosis more difficult due to tissue overlays; this can even make cancer detection impossible when using standard digital mammography. This could be remedied by Digital Breast Tomosynthesis (DBT), a further development of the current standard method for breast cancer detection. According to recent research results from the University of Münster, this method, which is being tested for the detection of breast cancer, is effective - even in women with high, and in particular extremely high, breast density. The results have now been published in the journal Radiology.

Although the evaluations of the ToSyMa study are not yet completely finished, one thing is already certain for the research group led by Prof. Walter Heindel, Director of the Clinic for Radiology at the University Hospital Muenster: Compared to the standard method of digital mammography, DBT in combination with synthetic mammography leads to more invasive breast cancer diagnosis. The background: The further development to DBT provides a technology that reduces superimposition effects due to tissue by calculating a pseudo-3D data set and thus shows diagnostic advantages. At the same time, the combination with so-called synthetic mammograms, which are being calculated from the tomosynthesis data sets, allows a comparison with images from previous examinations and a visual assessment of breast density.

The currently published ToSyMa subanalysis focused on breast cancer diagnosis in the four breast density categories. As a result, the detection rate of invasive breast cancer diagnoses using tomosynthesis among the approximately 8 percent of study participants who have extremely dense breast tissue, was about 250 percent higher than with the standard digital mammography method. "This suggests that mammography screening with Digital Breast Tomosynthesis significantly reduces radiological summation and superposition effects - and counteracts the limitations of digital mammography," says study manager Prof. Stefanie Weigel.

The extent to which the higher breast cancer detection rates also lead to higher levels of women's health remains to be determined. "To evaluate the long-term benefit of increased invasive breast cancer detection, data from the cancer registry will be integrated into the study for follow-up, in ToSyMy phase 2. The positive effect of early breast cancer detection through digital mammography screening on reducing breast cancer-specific mortality is already evident for Germany. Further development of mammography technology could further increase the effectiveness of the screening programme, especially for women with dense breast tissue," summarizes study leader Heindel.

From mid-2018 to the end of 2020, around 100,000 women participated in the German ToSyMa study. Embedded in the nationwide mammography screening program, 17 study centers in North Rhine-Westphalia and Lower Saxony participated in the diagnostic superiority study. The first evaluation of ToSyMa consisted of comparing the screening detection rates of invasive breast cancer in DBT and the common standard method - the result was a 48 percent increased detection rate in tomosynthesis (ToSyMa phase 1).

Contact for scientific information:
Prof. Walter Heindel
Clinic for Radiology, University Hospital Münster
E-Mail: heindel@uni-muenster.de
Phone: + 49 251 8347301

Original publication:
Breast Density and Breast Cancer Screening with Digital Breast Tomosynthesis: A TOSYMA Trial Subanalysis.
Weigel S, Heindel W, Hense HW, Decker T, Gerß J, Kerschke L; ToSyMa Screening Trial Study Group.
Radiology. 2022 Oct 4:221006. doi: 10.1148/radiol.221006