Monitoring Response to Neoadjuvant Chemotherapy Mammography or DBT is performed for initial diagnosis of the primary breast cancer. This procedure incompletely images the axilla, although pathologically enlarged stage I and II nodes may be included on the lateral and mediolateral oblique projections. FDG-PET/CT Skull Base to Mid-Thigh PET/CT is not routinely used for evaluation of the axilla after NAC as data are limited [4]. In several studies on detection of nodal disease, including a multicenter study of 360 patients, PET had disparate sensitivities (43%-79%) and specificities (66%-93%), possibly related to differences in tumor size in patient populations [109,110]. Given these limitations, this modality is not particularly useful to evaluate the axilla, and surgical sampling of the axillary nodes remains the standard of care. However, when an FDG-avid axillary node is seen on a pretreatment PET/CT scan, this is highly predictive of metastasis [111]. In addition, in node-positive tumors, PET/CT can be used to monitor response and possibly lead to sentinel node biopsy upon completion of chemotherapy rather than full axillary dissection [118]. Mammography Diagnostic There is no relevant literature to support the use of diagnostic mammography in initial imaging of the axilla after NAC [4]. Mammography or DBT is performed for initial diagnosis of the primary breast cancer. This procedure incompletely images the axilla, although pathologically enlarged stage I and II nodes may be included on the lateral and mediolateral oblique projections. MRI Breast Without and With IV Contrast The current literature evaluates performance of posttreatment MRI evaluation of the axilla only in the setting of baseline pretreatment imaging and/or clinically node-positive patients, as described below. These data cannot necessarily be extrapolated to initial imaging after completion of therapy in the absence of pretreatment axillary evaluation.
Monitoring Response to Neoadjuvant Systemic Therapy for Breast Cancer. Monitoring Response to Neoadjuvant Chemotherapy Mammography or DBT is performed for initial diagnosis of the primary breast cancer. This procedure incompletely images the axilla, although pathologically enlarged stage I and II nodes may be included on the lateral and mediolateral oblique projections. FDG-PET/CT Skull Base to Mid-Thigh PET/CT is not routinely used for evaluation of the axilla after NAC as data are limited [4]. In several studies on detection of nodal disease, including a multicenter study of 360 patients, PET had disparate sensitivities (43%-79%) and specificities (66%-93%), possibly related to differences in tumor size in patient populations [109,110]. Given these limitations, this modality is not particularly useful to evaluate the axilla, and surgical sampling of the axillary nodes remains the standard of care. However, when an FDG-avid axillary node is seen on a pretreatment PET/CT scan, this is highly predictive of metastasis [111]. In addition, in node-positive tumors, PET/CT can be used to monitor response and possibly lead to sentinel node biopsy upon completion of chemotherapy rather than full axillary dissection [118]. Mammography Diagnostic There is no relevant literature to support the use of diagnostic mammography in initial imaging of the axilla after NAC [4]. Mammography or DBT is performed for initial diagnosis of the primary breast cancer. This procedure incompletely images the axilla, although pathologically enlarged stage I and II nodes may be included on the lateral and mediolateral oblique projections. MRI Breast Without and With IV Contrast The current literature evaluates performance of posttreatment MRI evaluation of the axilla only in the setting of baseline pretreatment imaging and/or clinically node-positive patients, as described below. These data cannot necessarily be extrapolated to initial imaging after completion of therapy in the absence of pretreatment axillary evaluation.