Should tomosynthesis replace mammography?

Reuters Health - 20/04/2022 - Digital breast tomosynthesis plus synthesized two-dimensional mammography finds significantly more invasive breast cancers than digital mammography alone, according to results of the TOSYMA study.

Writing in The Lancet Oncology, the study team notes that 2D full-field digital mammography is the current standard of breast-cancer screening.

"Digital breast tomosynthesis generates pseudo-three dimensional datasets of the breast from which synthesized 2D (s2D) mammograms can be reconstructed. This innovative approach reduces the likelihood of overlapping breast tissues that can conceal features of malignancy," they explain.

TOSYMA was a multicenter, randomized, open-label superiority trial embedded in the German population-wide mammography screening program.

Over roughly two and a half years, nearly 100,000 women were randomly assigned (1:1) to digital breast tomosynthesis plus s2D mammography or digital mammography alone.

The results showed 48% greater odds of detection of invasive breast cancers in women screened with digital breast tomosynthesis plus s2D mammography compared with peers screened with digital mammography.

"Determination of interval cancer rates in the follow-up phase of the study will enable the investigation of incremental long-term benefits of digital breast tomosynthesis screening," Dr. Walter Heindel of the University of Munster, Germany, and colleagues note in their paper.

"Thus, the findings from TOSYMA 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," they add.

In a linked comment, Dr. Nehmat Houssami of the University of Sydney and Cancer Council NSW, in Australia, says the TOSYMA findings are in line with the results of a randomized controlled trial done in Italy, which also showed significantly higher rates of cancer detection using tomosynthesis with acquired 2D imaging than digital mammography.

"Results from meta-analyses have also confirmed that tomosynthesis increases cancer detection rate across age group and breast density strata and showed that increased cancer detection rate is most evident in biennial screening practice," Dr. Houssami says.

"In the absence of sufficient evidence for an effect on interval cancer rate, and no evidence on long-term outcomes, the concern that tomosynthesis could lead to over detection or could extend lead time without improving long-term outcomes will deter population screening programs from replacing mammography with tomosynthesis," Dr. Houssami writes.

"The increased screen-reading time for tomosynthesis, which was roughly double that of mammography in TOSYMA, although not the only barrier to adoption of tomosynthesis, represents a real-world resourcing challenge for screening programs tasked with screening a considerable proportion of the female population," Dr. Houssami points out.

Funding for the study was provided by the German Research Foundation. The authors have no relevant disclosures.

SOURCE: https://bit.ly/3xRGYnh and https://bit.ly/36nTWxt The Lancet Oncology, online April 12, 2022.

By Reuters Staff



Posted on 20 April 202226 April 2022