Use of sentinel lymph node biopsy to select patients for local-regional therapy after neoadjuvant chemotherapy.

Use of sentinel lymph node biopsy for axillary staging of patients with breast cancer treated with neoadjuvant chemotherapy has been widely debated. Questions arise regarding the accuracy of sentinel lymph node biopsy in axillary staging for these patients and its use to determine further local-regional therapy, including surgery and radiation therapy. For patients who are clinically node-negative at presentation, sentinel lymph node biopsy enables accurate staging of the axilla after neoadjuvant chemotherapy, and determination of which patients should go on to further axillary surgery and regional nodal radiation therapy. Importantly, performing axillary staging after completion of chemotherapy, rather than before chemotherapy, enables assessment of response to chemotherapy and the extent of residual disease. This information can assist the planning of adjuvant treatment. Recent data indicate that sentinel node biopsy can also be used to assess disease response after neoadjuvant chemotherapy for patients with clinical N1 disease at presentation.