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Sentinel node biopsy

Lymph nodes are important in the stage of your cancer

A sentinel lymph node biopsy may be done as part of your breast cancer surgery. This is done to find and remove important lymph nodes near your cancer called the sentinel lymph nodes. These nodes are removed during surgery so that they can be examined carefully for cancer. The biopsy is done to learn the extent of your cancer or to “stage it “.

What are lymph nodes and why are they important?

Lymph nodes are small, gland-like structures that are found in clusters in several areas of the body. They act as filters to trap bacteria (germs) and possibly cancer cells that may travel to lymph nodes close to the cancer.

In the breast, a group of lymph channels drain fluid and cells to a chain of lymph nodes in the axilla (armpit). The sentinel nodes are the very first lymph nodes in that chain to receive drainage from the area of the breast that contains the cancer cells.

Prior to surgery, you are given an injection of a substance that will settle in those sentinel nodes. The surgeon uses a special device (neoprobe) that can detect that substance within the lymph nodes. Sometimes, the surgeon will also inject a blue dye that can turn the lymph node blue. The goal is to find all of the sentinel nodes and remove them. The average number of lymph nodes typically removed for the sentinel lymph node biopsy is between 1 and 3.

The sentinel node:

The sentinel nodes are removed and then will be examined carefully. If there are no cancer cells found, then the surgeon will not remove any further lymph nodes from the axilla (armpit). If the sentinel nodes contain cancer cells, then the surgeon will remove more lymph nodes from the armpit area (called a complete axillary node dissection). Usually there will be a total of 10-30 lymph nodes removed with a complete node dissection. Sometimes we know on the day of surgery if the sentinel nodes contain cancer cells, but other times we do not find out until the final pathology report comes in several days after the surgery.

The procedure

  • The day of the surgery you will be directed to the Nuclear Medicine Department
  • You will be given several injections of a small amount of radioactive material (sulfur colloid) near the areola (dark skin around the nipple).
  • You will then wait for several hours so that the material can be absorbed by the lymph vessels and go into the sentinel lymph nodes. You will usually wait in the preoperative area during this time.
  • You will then go to the operating room for your surgery. After you go to sleep, your surgeon may inject blue dye to help identify the node. It may turn your urine blue-green.
  • Your surgeon will then identify the sentinel nodes and remove them. If the sentinel node cannot be found, then a complete axillary node dissection will be performed.