Our immune system functions as our body’s military force, defending us against infection and other diseases. Lymph vessels and lymph nodes are on the front lines of this system.
Lymph vessels transport a clear fluid called lymph throughout the body. The purpose of lymph fluid is to clean the body’s cells and to provide them with the oxygen and nutrients they need to survive.
Lymph nodes are small, round organs that filter harmful substances collected from the cells, such as bacteria and viruses, from the lymph fluid. If one of these invaders is found, the body triggers a response to take it down.
Groups of lymph nodes are located throughout the body, particularly in the underarms, neck, chest, abdomen and groin.
When a surgeon operates to remove a cancerous tumor, especially in breast cancers and melanoma, what’s called a “sentinel lymph node” may also be removed to determine whether the cancer has begun to spread.
“Before the use of sentinel lymph node biopsy for early-stage breast cancer, surgeons routinely removed most of the nodes from the axilla or armpit,” explains Brigid Killelea, MD, MPH, section chief of breast surgery at Yale Medicine. Removal of multiple nodes carries a higher risk of arm swelling, which is known as lymphedema, she notes. Typically, the sentinel lymph node procedure involves removal of one to three lymph nodes. “The rate of lymphedema with sentinel node biopsy is low, typically 5% or less,” says Dr. Killelea.