Axillary recurrences following positive sentinel lymph node biopsy with individual tumor cells or micrometastases and no axillary dissection.

The increased use of sentinel lymph node (SLN) excision for staging the axilla in women with breast cancer has benefited women by lowering morbidity and at the same time has raised issues related to the extent of treatment needed to the nodal basin. This is of particular concern when micrometastases or isolated tumor cells are found in the sentinel nodes on the final pathology. The probability of finding metastatic disease in non-sentinel lymph nodes (NSLN) ranges from 0 to 20% with only micrometastatic deposits in the SLN. Very low rates (0-3.7%) of axillary recurrence have been reported in selected patients with micrometastases tumor in sentinel nodes who have not had a completion axillary node dissection (ALND). Risk factors for additional positive NSLN include primary tumor size, the presence of lymphovascular invasion and the size of the SN metastatic deposit. Currently, the decision to not complete the ALND when micrometastic disease is found in the SLN should be made on a case-by-case basis. One should consider the tumor characteristics, findings within the SLN, and a multidisciplinary treatment plan. Clinical trial results may help to resolve the dilemma. There appears to be a low risk for axillary recurrence.