Tumor Characteristics and Molecular Subtypes in Breast Cancer Screening with Digital Breast Tomosynthesis: The Malmö Breast Tomosynthesis Screening Trial

Abstract

igital breast tomosynthesis (DBT) has the potential to become a widespread screening modality. Results from large prospective European population-based screening trials (1-3) have shown that DBT as a stand-alone modality or as an adjunct to digital mammography (DM; acquired or synthetic) improves the cancer detection rate by about 30% with acceptable recall rates compared with DM alone. Retrospective studies performed in the United States showed a more moderate improvement in cancer detection rates but a substantial reduction in recall rates (4). Before the broad implementation of DBT in screening, it is important to assess whether the detection of additional cancers leads to an actual screening benefit (ie, reduced breast cancer mortality) or whether mainly low-risk tumors are detected, potentially resulting in overdiagnosis. Because data from randomized DBT trials with breast cancer mortality as the outcome are likely to be limited, studies on cancer biology as a surrogate can elucidate this issue.Breast cancer is a heterogeneous disease in terms of its biologic profile and clinical manifestation. Histopathologic parameters, such as hormone receptor status and grade, and staging can be used for prognostic and predictive stratification. Classification of intrinsic subtypes on the basis of gene expression profiling can be used to further refine the stratification of invasive cancers (5). Because gene expression analysis is not always available, a practical approach was proposed by the St Gallen International Expert Consensus to use surrogate molecular subtyping on the basis of routine immunohistochemical and in situ hybridization analyses (6,7). The St Gallen classification consists of five

False-Negative Rates of Breast Cancer Screening with and without Digital Breast Tomosynthesis

“…DBT screening was associated with the detection of significantly higher rates of invasive cancers (P , .001), as well as fewer cancers with axillary nodal involvement and distant metastases, compared with DM. This is consistent with most of the current literature demonstrating that DBT enables detection of invasive cancers with favorable prognostic criteria and more treatment options (1,2,6,12,15,(20)(21)(22)(23)(24)(25)(26)(27). We also showed a trend toward lower ORs of FN examinations with advanced cancer characteristics for patients screened with DBT compared with DM.…”

Interval Breast Cancer Rates and Tumor Characteristics in the Prospective Population-based Malmö Breast Tomosynthesis Screening Trial

“…D igital breast tomosynthesis (DBT) has been shown to have higher sensitivity in screening than digital mammography (DM) (1)(2)(3)(4)(5). The additional invasive cancers detected at DBT seem to have similar or more favorable tumor characteristics than cancers detected at DM, such as higher proportions of small, spiculated, low-grade, luminal A-like tumors (4,(6)(7)(8). To determine whether the additional cancers detected at DBT constitute a potential screening benefit and do not simply contribute to overdiagnosis, interval cancer rates in DBT screening should be compared with those in DM screening (9).…”

An analysis of screen-detected invasive cancers by grade in the English breast cancer screening programme: are we failing to detect sufficient small grade 3 cancers?

“…Tomosynthesis certainly increases cancer detection, but the additional cancers are predominantly low grade [15,41] and to date, there has been no impact on interval cancer rates [12,42]. The additional detection of small grade 3 cancers is unclear, as grade size distribution has not been reported, but current evidence does not suggest that this is the answer to increasing the detection of small fast growing cancers destined to become interval cancers.…”