Despite this performance, approximately 14% of women with breast cancer and negative imaging for axillary metastasis ultimately have metastatic disease on sentinel lymph node biopsy [103]. US Breast Diagnostic mammography and US together can assess for extent of disease and tumor size. These imaging tests are usually already completed as part of the diagnostic workup (prior to pathological diagnosis). The sensitivity of US for detecting cancer ranges from 79% to 94% [22,25,104,105]. The addition of DBT to US improved sensitivity for detecting both primary breast cancer and multicentric and multifocal disease, from 82.6% (nondense) and 91.6% (dense) with US alone to 97.7% with combined DBT and US [106]. However, DBT and mammography have limited added value over US alone for initial evaluation in women <40 years of age [105]. Although bilateral US use in women with primary breast cancer to evaluate for multicentric and multifocal disease shows a lower sensitivity than MRI (85.1% versus 71.1%), US showed higher accuracy and specificity than MRI (67.6% versus 39.3% and 69.2% versus 60.2%, respectively), suggesting that bilateral US may be an acceptable alternative to MRI for locoregional staging [57]. When compared with DM alone, supplemental US more accurately depicted the extent of disease needing wider excision in 17 of 96 (18%) breasts for which conservation was anticipated, corresponding to 17 of 30 (57%) breasts with mammographically occult disease [22]. Based on mammography/clinical examination, 2% to 3% of patients have synchronous bilateral cancer [107]. This risk for bilateral synchronous cancer is increased in patients less than 55 years of age or in those diagnosed with invasive lobular subtypes [108]. In 1 series with 9% contralateral synchronous malignancy, mammography detected 60%, US detected 80%, and MRI detected 90% (with the remainder detected on follow-up imaging) [22].
Imaging of Invasive Breast Cancer. Despite this performance, approximately 14% of women with breast cancer and negative imaging for axillary metastasis ultimately have metastatic disease on sentinel lymph node biopsy [103]. US Breast Diagnostic mammography and US together can assess for extent of disease and tumor size. These imaging tests are usually already completed as part of the diagnostic workup (prior to pathological diagnosis). The sensitivity of US for detecting cancer ranges from 79% to 94% [22,25,104,105]. The addition of DBT to US improved sensitivity for detecting both primary breast cancer and multicentric and multifocal disease, from 82.6% (nondense) and 91.6% (dense) with US alone to 97.7% with combined DBT and US [106]. However, DBT and mammography have limited added value over US alone for initial evaluation in women <40 years of age [105]. Although bilateral US use in women with primary breast cancer to evaluate for multicentric and multifocal disease shows a lower sensitivity than MRI (85.1% versus 71.1%), US showed higher accuracy and specificity than MRI (67.6% versus 39.3% and 69.2% versus 60.2%, respectively), suggesting that bilateral US may be an acceptable alternative to MRI for locoregional staging [57]. When compared with DM alone, supplemental US more accurately depicted the extent of disease needing wider excision in 17 of 96 (18%) breasts for which conservation was anticipated, corresponding to 17 of 30 (57%) breasts with mammographically occult disease [22]. Based on mammography/clinical examination, 2% to 3% of patients have synchronous bilateral cancer [107]. This risk for bilateral synchronous cancer is increased in patients less than 55 years of age or in those diagnosed with invasive lobular subtypes [108]. In 1 series with 9% contralateral synchronous malignancy, mammography detected 60%, US detected 80%, and MRI detected 90% (with the remainder detected on follow-up imaging) [22].