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Introduction to Lymphedema
Lymphedema and Breast Cancer
There are three interconnecting lymphatic systems in the each breast. Each lymphatic system drains primarily to nodes in the axilla (armpit) with a small portion draining to other sites. Metastatic spread of breast cancer to the axilla occurs in up to 30% of patients and is the strongest prognostic factor for survival. In addition, involvement of the lymph nodes in the spread of disease is crucial for determining the course of treatment, such as whether to undergo chemotherapy, surgery, or radiation therapy.
Until recently, evaluation of the nearby lymph nodes for signs of metastatic spread has typically been carried out with a surgical procedure called axillary lymph node dissection (ALND) in which a pad of fat along the bundle of blood vessels and nerves that pass through the arm pit is removed. In this fat there are several lymph nodes which are removed and then studied by a pathologist to determine the presence of cancer cells. There are many side effects of this technique including pain, numbness, injury to the axillary vein, and lymphedema (up to 56% of women). The number of nodes removed increases the risk for development of lymphedema. ALND is still performed under necessary circumstances, such as the presence of a palpable mass in the armpit region of lymph nodes in the context of breast cancer.
A newer technique for mapping the involvement of lymph nodes in breast cancer is called sentinel lymph node (SLN) biopsy. It is performed to stage the axilla by identifying the first lymph node that would receive drainage from the tumor and evaluating it for the presence of cancer cells. The sentinel lymph node is the first lymph node closest to the breast tumor which is responsible for filtering out the cancer cells which may potentially spread beyond the armpit. Any spread of cancer is most likely to appear in this lymph node. The sentinel lymph node is determined by injecting a blue dye and/or a radioactive tracer into the area around the cancer. As the dye passes through the breast, it follows the same route that cancer cells traveling away from the tumor would follow. The surgeon typically removes the first node that takes up the dye (sentinel node) which is then examined by a pathologist. If cancer cells are detected, the surgeon may recommend the removal of additional lymph nodes and perhaps ALND. Because fewer lymph nodes are removed compared to ALND, the risk of lymphedema is reduced by up to 70% according to some estimates.
It is important to note that SLN is not designed to replace ALND and is not appropriate for all women diagnosed with breast cancer. It is of great importance, however, regardless of which procedure is to be performed, to choose a surgeon who has extensive experience in performing this surgery. There is an abundance of evidence that the rate of complications is considerably lower for patients whose surgeons were sufficiently experienced. This recommendation is also put forth by the International Society of Lymphology.
