ABSTRACT
The use of neoadjuvant chemotherapy (NACT) has been one of the major advances in breast surgery of the past two decades, rendering inoperable disease operable and reducing mastectomy rates. Biological therapies and polychemotherapy regimes have been able to deliver very high rates of pathological complete response in the breast and even higher rates in the axilla. This prompted interest in whether women with clinically node-positive disease could safely avoid axillary node clearance if their nodal disease responded to treatment. Critical to this question was whether a sentinel lymph node biopsy (SLNB) would be accurate in women with clinically involved nodes, with concerns that the lymphatic pathways would be damaged by their disease and reduce the biopsy's accuracy. The ACOSOG Z1071 trial set out to determine the false-negative rate (FNR) of post-NACT SLNB by performing both a SLNB and a clearance and comparing the accuracy of the two techniques. It concluded that accuracy was slightly lower than an acceptable level, but subsequent modifications have yielded improved results such that this technique is now acceptable. These modifications include removal of at least three nodes, use of dual tracers and more recently using targeted axillary dissection (TAD). The study was a key stepping-stone in axillary de-escalation.
