A machine equipped with breast tomosynthesis can perform 2D digital mammography, DBT, or a combination of both 2D mammography and DBT during a single compression. Radiation exposure from tomosynthesis is roughly equivalent to mammography. Therefore, adding tomosynthesis to mammography doubles the radiation dose, although it still is below the maximum allowable dose established in the Mammography Quality Standards Act.
Studies typically compare 1-view (ie, mediolateral oblique view), or more commonly, 2-view (mediolateral oblique plus craniocaudal view) breast tomosynthesis either alone or combined with standard 2D mammography, against standard 2D mammography alone. A 2014 TEC Assessment focused on 2-view tomosynthesis.9 The U.S. Food and Drug Administration (FDA), which reviewed this new modality in 2011, recommended that 2-view breast tomosynthesis is preferable to 1-view tomosynthesis (both used in combination with full field digital mammography).10
AUC: area under the curve; BI-RADS: Breast Imaging Reporting and Data System; DBT: digital breast tomosynthesis; mammo: mammography; NPV: negative predictive value; PPV: positive predictive value.
A large reading study was conducted in the U.K. National Health Service.39,40 Because the 2015 study included a mix of screening and diagnostic patients, case-selection bias limits extrapolation of the results to a screening population. The TOMosynthesis with digital MammographY (TOMMY) trial compared the performance of DM plus tomosynthesis with DM alone among women at moderate-to-high risk for breast cancer undergoing screening (n=1040 including 2 cancers) and women who had been recalled for a diagnostic workup after having a screening mammogram (n=6020 including 1158 cancers). After enrollment, these women had a mammogram and tomosynthesis; a synthesized mammogram (C-View) was also reconstructed from the tomosynthesis results. Comparisons were DM alone vs DM plus tomosynthesis vs synthetic mammogram plus tomosynthesis. The reference standard was pathology results for women who had a biopsy; the report did not note follow-up for other subjects. Sensitivity was 87% (95% CI, 85% to 89%) for DM only, 89% (95% CI, 25% to 91%) for DM plus tomosynthesis, and 88% (95% CI, 86% to 90%) for C-View images plus tomosynthesis. None of these differences were statistically significant. Specificity was 58% (95% CI, 56% to 60%) for DM alone, 69% (95% CI, 67% to 71%) for DM plus tomosynthesis, and 71% (95% CI, 69% to 73%) for C-View images plus tomosynthesis. Specificity for each of the combined modalities was statistically greater compared with DM alone (p
AUROC: area under the receiver operating characteristic curve; CC: craniocaudal; DBT: digital breast tomosynthesis; DM: digital mammography (2-view unless noted otherwise); MLO: mediolateral oblique; NPV: negative predictive value; NR: not reported; PPV: positive predictive value; SCV: supplemental assessment views.
BI-RADS: Breast Imaging Reporting and Data System; CI: confidence interval; DBT: digital breast tomosynthesis; DM: digital mammography; Mammo: mammography; MBTST: Malmö Breast Tomosynthesis Screening Trial; NR: not reported; PPV: positive predictive value; s2D: synthesized 2D mammography; STORM: Screening with Tomosynthesis OR standard Mammography.
The question addressed in this portion of the evidence review is whether there is sufficient evidence that digital breast tomosynthesis (DBT), used to screen for breast cancer, improves the net health outcome compared with standard techniques. Specifically, is DBT as an adjunct to mammography or DBT plus synthesized 2-dimensional (2D) mammography superior to mammography alone, and is DBT instead of mammography at least as beneficial as mammography? For both interventions, are differences in accuracy likely to improve health outcomes via earlier diagnosis and treatment?
DBT: digital breast tomosynthesis; FDA: Food and Drug Administration; FFDM: full field digital mammography; PMA: premarket approval; 2D: 2-dimensional; 3D: 3-dimensional.
“…breast tomosynthesis has shown to be an advance over digital mammography, with higher cancer detection rates and fewer patient recalls for additional testing…. Better sensitivity will likely translate into more lives saved. Lower recall rates result in fewer patients who may experience short-term anxiety awaiting test results. This is important evidence that tomosynthesis will have a positive impact on patient care.…”
· Approval for multiple projection views to produce 3D digital mammography images for screening and diagnosing breast cancer. Senographe uses similar DBT technology as SenoClaire and consists of software and hardware upgrade to reconstruct tomosynthesis images.
While ACR has encouraged additional study of breast tomosynthesis, focusing on long-term clinical outcomes and better definition of subgroups, it concluded that “To be clear: tomosynthesis is no longer investigational. Tomosynthesis has been shown to improve key screening parameters compared to digital mammography.”
Digital breast tomosynthesis (DBT) was developed to improve the accuracy of mammography by capturing a group of tomograms of the breast, further clarifying areas of overlapping tissue. Developers proposed that its use would result in increased sensitivity and specificity, as well as fewer recalls due to inconclusive results.6 DBT produces multiple low-dose images per view along an arc over the breast. During breast tomosynthesis, the compressed breast remains stationary while the x-ray tube moves approximately 1° for each image in a 15° to 50° arc, acquiring 11 to 49 images.7 These images are projected as cross-sectional “slices” of the breast, with each slice typically 1-mm thick. Adding breast tomosynthesis takes about 10 seconds per view. In a 2009 study in a research setting, mean time (standard deviation) for interpretation of results was 1.22 (1.15) minutes for digital mammography and 2.39 (1.65) minutes for combined digital mammography and breast tomosynthesis.8
ACR’s Appropriate Criteria, last reviewed in 2016, gave digital breast tomosynthesis (DBT) a rating of 9 (“usually appropriate”) for use with women at high risk, intermediate risk, as well as average risk for breast cancer.54 The ACR screening recommendations for breast cancer risk are: