Over the past 10–15 years, sentinel lymph node (SLN) biopsy (SLNB) has become the standard of care in the management of breast cancer, limiting completion axillary lymph node dissection (cALND) to patients with positive sentinel nodes. Non-SLN metastases are present in 40–50% of SLN-positive patients [1,2] and are predicted by the same variables that may predict metastasis to the SLN, the most important being tumor size and lymphovascular invasion. Several groups have developed models for patients with a positive SLN to predict the likelihood of having additional positive non-SLNs. A widely used nomogram developed at Memorial Sloan–Kettering Cancer Center (NY, USA) by Van Zee et al. is an online tool that calculates the estimated risk of positive non-SLNs based on the following factors, pathologic primary tumor size, tumor histology and grade, number of positive SLNs, number of negative SLNs, presence of lymphovascular invasion, multifocality, estrogen receptor (ER) positivity, and method of detection of SLN metastasis [3]. The nomogram has been validated by other institutions [4–6] and predicts non-SLN metastases much more accurately than expert clinicians’ best estimates [7]. Furthermore, the residual axillary nodal disease may be well controlled and perhaps eradicated with current multimodality treatment, particularly when radiation therapy is delivered. With the ability to stage patients as nodepositive or -negative through SLNB in an era of improved multimodality therapy, the next clinical question to be addressed was the need for cALND for local control and its impact on survival in the face of positive SLNB. The prospective American College of Surgeons Oncology Group (ACOSOG) Z11 trial randomized breast cancer patients who underwent lumpectomy and SLNB and were found to have positive nodes for cALND, versus no further surgery. The study was limited to clinically node-negative women with cancers ≤5 cm in size treated with lumpectomy and radiation therapy with ≤2 positive nodes and no extracapsular extension. Additional positive axillary nodes were found in 27% of the cALND arm. With a median followup of 6.3 years, there were no significant