What is a “sentinel” node?
When a patient is diagnosed with breast cancer, it is important to find out if the cancer has spread. One of the first places that a breast cancer can spread to is the axilla (arm pit). As part of the staging and treatment of breast cancer, it is important to evaluate the lymph nodes in the axilla. We have recently learned that there are certain lymph nodes that a tumor will spread to first before it spreads to any of the other nodes. This first node is called the sentinel node, and it may be in a different location in different patients. It has been recently demonstrated that if the sentinel node is free of cancer all the other lymph nodes will most probably be free of cancer as well. This fact is being used to help us evaluate whether a breast cancer has spread to the lymph glands in the axilla. By injecting a slightly radioactive substance into the area around a tumor in the breast, we can see which lymph glands concentrate this substance; this is called sentinel node mapping. This
