Lymph Node Assessment
Whether the patient chooses breast conserving surgery or mastectomy, there almost always will be an accompanying procedure to assess the status of the lymph glands under the arm on the side of the cancer. Today, if the pre-operative evaluation suggests the lymph nodes are unlikely to contain cancer, then the patient will have a sentinel node biopsy. This procedure tries to identify several of the lymph nodes that would be first to trap cancer cells should they spread through the breast lymph channels into the lymph glands under the arm. If these sentinel lymph glands are free of cancer, then there is no reason to remove any additional lymph glands. If cancer cells are found in the sentinel lymph node, it will often necessitate the removal of many other lymph glands. This procedure is referred to as an axillary lymph node dissection.
The sentinel node procedure should be done whenever indicated since it lessens the magnitude of the surgery and reduces the incidence of post-operative swelling of the arm, called lymphedema. Lymphedema can occur in approximately 20%1 of women having the axillary lymph node dissection. After a sentinel node procedure, there is a 6%1 incidence of lymphedema, but this is a significant reduction in the frequency of this post-operative problem.
Sentinel Lymph Node Biopsy / Axillary Dissection - The first lymph node that cancer cells spread to is the sentinel lymph node. A biopsy of this node can help to determine the extent and stage of the breast cancer. This surgery is usually done in conjunction with the lumpectomy or mastectomy. A small incision is made under the arm, and with the aid of a radioactive substance and/or blue dye and a special radioactivity detection device to find the sentinel node, the surgeon is able to remove the sentinel node. The sentinel node(s) will be examined by a pathologist. If cancer is found in only one or two lymph nodes and the patient is having a lumpectomy plus radiation, no further lymph node removal may be required. If more than two lymph nodes are found to have cancer or the patient is having a mastectomy, additional lymph nodes would be removed (referred to as an axillary dissection).
References: 1 ACOSOG Z11 Trial, NCCN Physician Guidelines, and NCCN Patient Guidelines- http://www.nccn.org/patients/patient_guidelines/breast/index.html