Sentinel Lymph Node Dissection The dictionary defines "sentinel" as a guard, watchdog, or protector. Likewise, the sentinal lymph node is the first node "standing guard" for your breast. A dye and a tracer are injected into the breast prior to the surgery. This dye and tracer map out the lymphatics of the breast. The sentinel lymph node is the very first lymph node that filters fluid draining away from the breast. This lymph node is a good predictor of the other lymph nodes in the axilla. The surgeon uses the dye and tracer to find the sentinel lymph node or nodes (1-4 nodes usually). If the sentinel lymph node has cancer in it then an axillary dissection (removal of the axillary lymph nodes) is done. If the sentinel lymph node(s) do not have cancer in them, that is good predictor that no other lymph nodes are involved as well and so no further lymph nodes are removed. This allows fewer normal lymph nodes to be removed and so decreases the risk of lymphedema, or swelling of the arm after surgery.

NOTE: Whether mastectomy or breast conserving surgery is performed, systemic therapy is often offered as well. Most patients will see a medical oncologist to discuss systemic treatment which could include such treatments as chemotherapy, anti-estrogen therapy, and/or gene therapy.