The sentinel node is the lymph node that is most likely to contain spread of cancer. If a breast cancer spreads to the lymph nodes, it is usually to the lymph nodes in the armpit (axilla). Up until fairly recently it was routine to remove most of the axillary lymph nodes in women diagnosed with breast cancer. The sentinel node technique has allowed surgeons to be more selective in removing the axillary lymph nodes. This has significantly reduced the rate of lymphedema (arm swelling) after a lymph node operation.

The operation is performed in women with breast cancer that is invasive, and in some women with in situ cancer (cancer that hasn’t broken through the duct walls). Usually the operation involves injection with a radioactive protein either the afternoon before or the morning of, and a blue dye immediately before the operation. These compounds flow through tiny channels throughout the breast (lymphatic channels) and collect in the sentinel node(s). There is frequently more than one sentinel node. The blue dye allows visualization of the lymphatic channel and/or lymph node. The radioactive protein allows identification of the sentinel node by use of a gamma counter (medical Geiger counter), and the lymph node will appear as a “hot spot”.

Women who have diagnosed spread of cancer to the axillary lymph nodes are not candidates for this procedure. A quick test will be done during the operation to check for evidence of spread of the cancer to the node. If there is spread, a complete axillary lymph node removal will be performed.

Dr. Galloway received her training in sentinel node biopsy technique at Ohio State University in 1998.