Mammography Diagnostic Mammography can reliably be used to assess response of a primary breast malignancy to NAC. However, it is less useful in assessing axillary nodal response to therapy given that the axilla is incompletely visualized. MRI Breast In patients who have had axillary nodal metastatic disease diagnosed prior to NAC for breast cancer, there is little consensus on how to image the axilla subsequently. MRI has some limitations in evaluating the axilla and is unlikely to be the sole imaging test for estimating residual tumor burden preoperatively [121]. However, a combination of tests with axillary US, MRI, or FDG-PET/CT may be the future direction for clinical trials trying to answer such questions (https://clinicaltrials.gov/ct2/show/NCT03188393). At least one study suggests that measurements at 360 seconds after contrast administration provides the most accurate measurements of size, compared with the earlier phase or the later phase of the dynamic series [137]. Imaging of the Axilla Most of the literature focuses on the evaluation of response of the primary breast tumor after NAC and MRI superiority to mammogram, US, and physical examination in this setting [124]. The performance of MRI for the primary breast lesion cannot be extrapolated to 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 Because of its noninvasive nature, axillary US may evaluate for residual axillary nodal disease despite its PPV of 60% to 81%, NPV of 43% to 74%, and specificity of 37% to 92% [138]. However, the sensitivity of US (71%) for prediction of residual nodal metastatic disease was higher than that of clinical examination and MRI/PET in most studies [139].
Imaging of the Axilla. Mammography Diagnostic Mammography can reliably be used to assess response of a primary breast malignancy to NAC. However, it is less useful in assessing axillary nodal response to therapy given that the axilla is incompletely visualized. MRI Breast In patients who have had axillary nodal metastatic disease diagnosed prior to NAC for breast cancer, there is little consensus on how to image the axilla subsequently. MRI has some limitations in evaluating the axilla and is unlikely to be the sole imaging test for estimating residual tumor burden preoperatively [121]. However, a combination of tests with axillary US, MRI, or FDG-PET/CT may be the future direction for clinical trials trying to answer such questions (https://clinicaltrials.gov/ct2/show/NCT03188393). At least one study suggests that measurements at 360 seconds after contrast administration provides the most accurate measurements of size, compared with the earlier phase or the later phase of the dynamic series [137]. Imaging of the Axilla Most of the literature focuses on the evaluation of response of the primary breast tumor after NAC and MRI superiority to mammogram, US, and physical examination in this setting [124]. The performance of MRI for the primary breast lesion cannot be extrapolated to 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 Because of its noninvasive nature, axillary US may evaluate for residual axillary nodal disease despite its PPV of 60% to 81%, NPV of 43% to 74%, and specificity of 37% to 92% [138]. However, the sensitivity of US (71%) for prediction of residual nodal metastatic disease was higher than that of clinical examination and MRI/PET in most studies [139].