Sentinel Node Biopsy
In a sentinel node biopsy, a radioactive substance is injected into the area around the tumor. Lymphatic vessels carry these materials to the sentinel lymph node (the first lymph node to which the cancer is likely to spread). The doctor can see the blue dye or detect the radioactivity in the sentinel node, which is removed and examined. If the sentinel node contains cancer, more axillary lymph nodes (lymph nodes in the armpit) are removed.

Axillary Lymph Node Dissection
If a sentinel node biopsy shows the sentinel node (the first lymph node to which the cancer is likely to spread) is cancerous, axillary lymph nodes (lymph nodes in the armpit) will need to be removed. This surgical procedure allows doctors to determine if breast cancer has spread to those nodes and to remove any cancerous lymph nodes.

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