MRI Breast The role of breast MRI in detecting residual tumor within the axillary lymph nodes remains questionable [121]. Based on a 26-study meta-analysis, MRI has moderate sensitivity (77%) and specificity (90%) for detecting residual disease after NAC [122,123]. Most of the literature confirms the superiority of MRI in detecting residual tumor within the breast after NAC compared with mammography, US, and physical examination [124]. However, it is not proven that preoperative MRI is associated with improved surgical outcomes or lower recurrence rates [125]. A meta-analysis of 44 studies reported MRI sensitivity for detecting residual disease in the breast was 92% and a specificity of 90% [124]. MRI also demonstrates higher accuracy in triple negative tumors and HER2-positive tumors [126-128]. The performance of MRI for the primary breast lesion cannot be extrapolated into MRI performance of the axillary nodal disease [112]. Therefore, MRI is not used routinely for predicting response of axillary nodal disease. Sestamibi MBI There is no relevant literature supporting the use of Tc-99m sestamibi MBI for assessing response after treatment with NAC. US Axilla The role of axillary US to assess the axilla after NAC remains controversial [7]. Most of the data from multicenter trials involve patients with initial clinical node-positive disease [129,130]. These studies, evaluating SLNB after NAC, report that the accuracy rates of SLNB are acceptable. With the variable sensitivity and specificity of axillary US, even in combination with percutaneous biopsy, axillary US is not able to replace SLNB. Therefore, axillary US may not assess axillary response after chemotherapy. Variant 9: Female. Breast cancer, greater than 2 cm in size, clinical node-positive. Imaging of the axilla after completion of neoadjuvant chemotherapy and prior to surgery. NAC is used to treat operable large tumors, nonoperable locally advanced tumors, and inflammatory breast cancers prior to definitive surgical management.
Imaging of the Axilla. MRI Breast The role of breast MRI in detecting residual tumor within the axillary lymph nodes remains questionable [121]. Based on a 26-study meta-analysis, MRI has moderate sensitivity (77%) and specificity (90%) for detecting residual disease after NAC [122,123]. Most of the literature confirms the superiority of MRI in detecting residual tumor within the breast after NAC compared with mammography, US, and physical examination [124]. However, it is not proven that preoperative MRI is associated with improved surgical outcomes or lower recurrence rates [125]. A meta-analysis of 44 studies reported MRI sensitivity for detecting residual disease in the breast was 92% and a specificity of 90% [124]. MRI also demonstrates higher accuracy in triple negative tumors and HER2-positive tumors [126-128]. The performance of MRI for the primary breast lesion cannot be extrapolated into MRI performance of the axillary nodal disease [112]. Therefore, MRI is not used routinely for predicting response of axillary nodal disease. Sestamibi MBI There is no relevant literature supporting the use of Tc-99m sestamibi MBI for assessing response after treatment with NAC. US Axilla The role of axillary US to assess the axilla after NAC remains controversial [7]. Most of the data from multicenter trials involve patients with initial clinical node-positive disease [129,130]. These studies, evaluating SLNB after NAC, report that the accuracy rates of SLNB are acceptable. With the variable sensitivity and specificity of axillary US, even in combination with percutaneous biopsy, axillary US is not able to replace SLNB. Therefore, axillary US may not assess axillary response after chemotherapy. Variant 9: Female. Breast cancer, greater than 2 cm in size, clinical node-positive. Imaging of the axilla after completion of neoadjuvant chemotherapy and prior to surgery. NAC is used to treat operable large tumors, nonoperable locally advanced tumors, and inflammatory breast cancers prior to definitive surgical management.