Lymph node dissection is a surgical procedure in which several lymph nodes are removed from the underarm. This is also called an axillary lymph node dissection. The nodes are examined under a microscope to see if the breast cancer has spread into them.
Lymph nodes filter the lymph fluid, a clear-to-white fluid that helps nourish tissues and helps remove damaged cells (including cancer cells), bacteria, and viruses from the tissues. Lymph nodes are an important part of the immune system and contain many white blood cells, including special white blood cells called lymphocytes and macrophages, which are key components of the immune system and help the body fight off infection and remove damaged cells, like cancer cells. When cancer mutates so that it evades the immune system, these natural defenses do not recognize cancer, and cancer can grow and spread. When breast cancer spreads, it often first spreads to the axillary lymph nodes. Lymph node dissection allows doctors to understand the extent of an individual’s cancer to guide treatment decisions.1,2
The sentinel lymph node
The sentinel lymph node is the first lymph node in the chain of lymph nodes that drain the lymph fluid from the breast. In sentinel lymph node biopsy, only the first one to several lymph nodes that are the primary drainage point for the breast are removed. To identify which lymph node(s) are sentinel, a radioactive substance or dye is injected into the breast near the tumor. This dye drains to the sentinel node, making it visible for the surgeon to identify. If there is no cancer found in the sentinel node(s), it is generally unlikely that there will be cancer in the other axillary lymph nodes.3,4
Possible side effects of surgery to the lymph nodes
Short-term side effects of surgery to the lymph nodes may include pain, swelling, bleeding, and a risk of infection. Surgery to the underarm area may also cause stiffness or numbness, limiting the movement of the arm.1
There are also possible long-term side effects of surgery to the lymph nodes. Both sentinel lymph node biopsy and axillary lymph node dissection increase the risk of developing lymphedema, an irregular swelling in the arm or chest. When there are fewer lymph nodes to do the job of draining the lymph fluid, this swelling can occur due to a cut on the arm or hand, infection, or trauma to the arm. Because the risk of lymphedema increases with the number of lymph nodes removed, the chances of developing lymphedema are generally less with sentinel lymph node biopsy than with axillary lymph node dissection. There are ways to treat lymphedema, and any signs of swelling should be immediately reported to a doctor.1,3
What to expect
The surgery to test the axillary lymph nodes for cancer usually takes about an hour, although the time to be admitted varies by location. In certain cases, the lymph node biopsy is done at the same time as breast surgery, such as a lumpectomy or mastectomy. The surgery is done using general anesthesia, a medication that puts the patient to sleep for the procedure.5
Once the lymph nodes have been removed, they are sent to a pathology laboratory to be examined under a microscope. It can take several days to get the pathology report.5
Recovery time after surgery is very individual. To aid in recovery and minimize side effects, physical therapy exercises may be recommended to help restore range of motion and strength in the affected arm.5
Lymph node surgery for breast cancer. American Cancer Society. Available at https://www.cancer.org/cancer/breast-cancer/treatment/surgery-for-breast-cancer/lymph-node-surgery-for-breast-cancer.html. Accessed 10/8/18.
Overview of the lymphatic system. Merck Manual. Available at https://www.merckmanuals.com/home/heart-and-blood-vessel-disorders/lymphatic-disorders/overview-of-the-lymphatic-system. Accessed 10/8/18.
Sentinel lymph node biopsy for early stage breast cancer. American Society of Clinical Oncology. Available at https://www.cancer.net/research-and-advocacy/asco-care-and-treatment-recommendations-patients/sentinel-lymph-node-biopsy-early-stage-breast-cancer. Accessed 10/8/18.
Lumpectomy. Mayo Clinic. Available at https://www.mayoclinic.org/tests-procedures/lumpectomy/about/pac-20394650. Accessed 10/5/18.
Lymph node dissection: what to expect. BreastCancer.org. Available at https://www.breastcancer.org/treatment/surgery/lymph_node_removal/dissection_expectations. Accessed 10/8/18.