Imaging of the axilla before preoperative chemotherapy: implications for postmastectomy radiation.

Postmastectomy radiation therapy (PMRT) improves breast cancer survival in many women with lymph node-positive disease who undergo surgery followed by adjuvant chemotherapy. The role of PMRT after women receive neoadjuvant chemotherapy (NAC) is less clear. The available data suggest that clinical extent of disease at presentation before NAC, pathologic residual disease (especially pathologically involved lymph nodes) after NAC, and response to NAC are key prognostic factors for locoregional recurrence. Therefore, accurate axillary staging before the initiation of NAC and assessment of response to chemotherapy are critically important. Here, the authors review the literature addressing the radiotherapy management of patients with breast cancer who received NAC and underwent mastectomy with a special focus on the imaging modalities used to assess axillary lymph node status.