Optimal management of patients with a positive sentinel lymph node

Sentinel lymph node biopsy has revolutionized breast cancer surgery, obviating axillary lymph node dissection as a staging procedure in clinically node-negative patients. Concomitantly, improved pathologic assessment of the sentinel lymph node has led to the discovery of progressively smaller quantities of metastases, the clinical importance of which has not yet been established. Sentinel lymph node metastases can now be organized into three categories of decreasing size: macrometastases, micrometastases, and isolated tumor cells. Although the standard of care is to perform an axillary dissection for patients with macro- or micrometastases, certain subsets of patients may fare well without an axillary dissection. Axillary radiation in positive sentinel node management is also a subject of ongoing investigation, especially in light of long-term survival data equivalent to that of axillary lymph node dissection. Isolated tumor cells are of undetermined significance and do not require completion axillary dissection when discovered in the absence of other sentinel node findings. This article discusses management recommendations in the context of macrometastasis, micrometastasis, and isolated tumor cells.