Sentinel Lymph Node Biopsy/Low Axillary Lymph Node Dissection:
Following injection of a radioactive isotope in the Department of Nuclear Medicine at Rush University Medical Center, the sentinel node will be identified in surgery with a gamma probe which will be excised for staging. Additional lymph nodes may be removed depending on the individual case.
Sentinel node is the first lymph gland, usually found in the arm pit, to which the cancer cells spread. Thus if the cancer cells could break away from their site of origin in the milk ducts and glands, the first destination would be the sentinel node. One could find the location of this node by sentinel node mapping. Sentinel node mapping (fig. D) for breast cancer is achieved by injecting a radioactive substance or blue dye around the tumor site or under the nipple skin just before the operation. This will guide the surgeon to the site of the sentinel node. The tracer accumulates in the sentinel node and sends signals which are detected by a special probe or stains the node blue if the dye technique is used. During the operation, the surgeon identifies the sentinel node (average of two) and removes them for the pathologist to examine. This is a smaller but smarter operation to establish whether or not the cancer has spread. Patient’s recovery is shorter and the risk of lymphedema is greatly reduced (ref. 4). The previous operation, axillary node dissection, consisted of removing 15-20 lymph nodes, which was associated with more post-operative pain and the risk of arm swelling. An additional advantage of the sentinel node biopsy is that the pathologist has more time to examine more carefully multiple sections from 2 instead of 20 nodes and provide more accurate report (refs. 5&6).