In addition to its role in the initial diagnostic workup, US is important in the secondary evaluation of a suspicious finding on MRI in the setting of evaluation of disease extent. US sensitivity and NPV are higher than those of DBT [109]. Compared with DBT, US showed a lower specificity (98.1% versus 78.9%) and similar PPV (66.7% versus 52.2%). However, a meta-analysis of second-look US following a suspicious finding on MRI showed heterogeneity in US performance, with the detection rate ranging from 22.6% to 82.1% (pooled detection rate 57.5%) and an 87.8% pooled NPV [110]. Therefore, a negative US is insufficient to obviate the need for an MRI biopsy in this setting. There is no evidence supporting US as an accurate method for determining disease extent of those diagnosed with ILC subtype. Conventional imaging with mammography and/or US can significantly underestimate the extent of ILC [26,111-114]. For example, US specifically underestimated ILC tumor size by 27% (95% CI, 17%-37%) in a Imaging of Invasive Breast Cancer study [113], and a different study showed that the greatest discrepancy between tumor size and pathologic size using US measurements was for the ILC subtype [26]. Variant 2: Newly diagnosed. Clinical stage I-IIA (early stage) breast cancer at presentation. Evaluation for distant disease (includes IDC, or ILC, or NOS). It has long been recognized that steroid receptor expression reflects intrinsic biologic diversity in breast cancer with treatment and survival implications, also determining patterns of metastatic spread. Historically, bone is the most likely site of breast cancer metastases (51%), followed by liver/soft tissue (19%), pleura (16%), lung (14%), and brain (4%) [115]. The higher percentage of bone metastases from breast cancer appears to be driven primarily by the majority of primary tumors expressing ER and/or PR.
Imaging of Invasive Breast Cancer. In addition to its role in the initial diagnostic workup, US is important in the secondary evaluation of a suspicious finding on MRI in the setting of evaluation of disease extent. US sensitivity and NPV are higher than those of DBT [109]. Compared with DBT, US showed a lower specificity (98.1% versus 78.9%) and similar PPV (66.7% versus 52.2%). However, a meta-analysis of second-look US following a suspicious finding on MRI showed heterogeneity in US performance, with the detection rate ranging from 22.6% to 82.1% (pooled detection rate 57.5%) and an 87.8% pooled NPV [110]. Therefore, a negative US is insufficient to obviate the need for an MRI biopsy in this setting. There is no evidence supporting US as an accurate method for determining disease extent of those diagnosed with ILC subtype. Conventional imaging with mammography and/or US can significantly underestimate the extent of ILC [26,111-114]. For example, US specifically underestimated ILC tumor size by 27% (95% CI, 17%-37%) in a Imaging of Invasive Breast Cancer study [113], and a different study showed that the greatest discrepancy between tumor size and pathologic size using US measurements was for the ILC subtype [26]. Variant 2: Newly diagnosed. Clinical stage I-IIA (early stage) breast cancer at presentation. Evaluation for distant disease (includes IDC, or ILC, or NOS). It has long been recognized that steroid receptor expression reflects intrinsic biologic diversity in breast cancer with treatment and survival implications, also determining patterns of metastatic spread. Historically, bone is the most likely site of breast cancer metastases (51%), followed by liver/soft tissue (19%), pleura (16%), lung (14%), and brain (4%) [115]. The higher percentage of bone metastases from breast cancer appears to be driven primarily by the majority of primary tumors expressing ER and/or PR.