In the old days, following a breast cancer diagnosis, all of the lymph nodes in the armpit were routinely removed (often 30-40 nodes). All of that has changed. Sentinel lymph node biopsy generally removes only 1 or 2 lymph nodes and has proven to be a highly accurate way of identifying breast cancer that has spread to axillary lymph nodes. This is important for staging the cancer and determining a more accurate and tailored treatment plan.
Lymph nodes are found throughout the body, including underneath the arm, above the collarbone and in the chest. If cancer has spread outside the breast, it is often first found in the lymph nodes in the armpit. That’s why lymph nodes under the arm (axillary nodes) are examined during breast cancer surgery.
If the sentinel lymph nodes are negative, no additional lymph nodes need to be removed.