Sentinel Node Biopsy

Last Modified: January 24, 2012


What is a sentinel node biopsy?


Christine Hill-Kayser, MD, Radiation Oncologist, responds:

When a surgeon performs a sentinel node biopsy, he or she uses a blue dye or mild radioactive tracer to identify the lymph nodes that are most likely to have drained the area of a known tumor. For example, there are as many as 100 lymph nodes in the axillary, or armpit, area. Fluid called lymph travels from the breast to these nodes, and may carry cancer cells with it. Usually, 1-3 nodes serve as gateway, or sentinel, lymph nodes. If any cancer cells have traveled from the breast to the lymph nodes, they are most likely to e caught by these few gateway nodes. Large clinical trials have shown that removing these gateway nodes will give the surgeon as much information about whether the cancer has spread to lymph nodes as removing 20 or more lymph nodes will. The benefit of removing only the gateway nodes is that the patient will be at much less risk for lymphedema after removal of only a few nodes compared to removal of 10 or more nodes.

This question and answer was part of the OncoLink Brown Bag Chat Series. View the entire Interpreting Test Results transcript.

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