While breast surgeons and medical oncologists have long "accepted" the complications of standard axillary node dissection (including chronic arm swelling, pain, and risk of infection), efforts to develop a more tolerable, yet accurate, nodal assessment remain a major focus in the surgical management of breast cancer.
Sentinel node mapping or sentinel lymphadenectomy (SLND) is a new technique in which the initial lymph node at risk for harboring metastatic disease (the "sentinel node") is identified during the operation. If this node is positive for cancer, it can be assumed that the nodes that branch off from this node will also be positive. The reverse also holds true.
Using a combination of blue-staining dye and the radioisotope technetium, the sentinel node can be localized in 93-97% of patients. Furthermore, several institutions have reported large numbers of patients whose sentinel node status has shown a predictive accuracy of 96-100%. These findings have led a number of groups to eliminate routine axillary node dissection in sentinel node-negative patients, thus avoiding the complications of more invasive surgery.
The more difficult question remains how to best manage the sentinel node-positive patient. While the standard of care remains full axillary node dissection, several institutions are evaluating the use of axillary node radiation. Furthermore, given the routine use of adjuvant chemotherapy in this setting, the overall significance of detecting further nodal micrometastases remains unclear.