Malmö Breast Tomosynthesis Screening Trial (MBTST)

To compare digital breast tomosynthesis (DBT) with full field digital mammography (FFDM) regarding effectiveness as screening modalities.

Mammography is the only approved method for breast cancer screening, but not all tumors can be detected with mammography. The main reason is overlapping structures that can either mimic or hide a tumor on a 2-dimensional image like mammography. Digital breast tomosynthesis, (DBT) is a 3-dimensional x-ray technique that has been developed during the last years. A tomographic technique like DBT, which reduces or eliminates the detrimental effect of over- and underlying tissue, can probably help to find more tumors. This study aims to investigate whether more breast cancers can be detected with DBT compared to full field digital mammography (FFDM) in population invited to screening. An interim analysis will be performed during 2013 including the first 7,500 women of the study cohort.

Single-armed study. Women are their own controls with paired images of digital mammography and breast tomosynthesis.

Women in the study will once undergo both standard FFDM screening (2-views) and DBT (1 view, MLO). This will result in a doubled radiation dose compared to only 2-view FFDM, which is the standard procedure for women in the screening program.

Sensitivity and specificity for breast cancer detection will be assessed for DBT and DM respectively. The following screening performance measures will also also investigated: the number of detected cancers per 1000 women screened, the number of recalled women/100 screens (recall rate) after consensus, and the positive predictive value (PPV) for screen-recall and the negative predictive value (NPV), in both reading arms. Analyses of the contribution from different reading steps will be investigated. A follow-up period of 24 months after the intervention period will provide information on the actual numbers of breast cancers in the study population through record linkage with the Swedish Cancer Registry.

To investigate the biological characteristics of the cancers in the trial by mode of detection (screening detected, interval cancers)

Inclusion Criteria: women 40-74 years old in the regular population based mammographic screening program in Malmö, Sweden. Exclusion Criteria: pregnancy and women not speaking English or Swedish -

Dahlblom V, Andersson I, Lang K, Tingberg A, Zackrisson S, Dustler M. Artificial Intelligence Detection of Missed Cancers at Digital Mammography That Were Detected at Digital Breast Tomosynthesis. Radiol Artif Intell. 2021 Sep 1;3(6):e200299. doi: 10.1148/ryai.2021200299. eCollection 2021 Nov.

Zackrisson S, Lang K, Rosso A, Johnson K, Dustler M, Fornvik D, Fornvik H, Sartor H, Timberg P, Tingberg A, Andersson I. One-view breast tomosynthesis versus two-view mammography in the Malmo Breast Tomosynthesis Screening Trial (MBTST): a prospective, population-based, diagnostic accuracy study. Lancet Oncol. 2018 Nov;19(11):1493-1503. doi: 10.1016/S1470-2045(18)30521-7. Epub 2018 Oct 12. Erratum In: Lancet Oncol. 2019 Jan;20(1):e9.