Breast surgery: Sentinel Lymph Node Biopsy

What is a Sentinel Lymph Node Biopsy for breast surgery?

The sentinel lymph node is the first lymph node that lymph fluid drains to from the breast, and therefore the lymph node to which cancer cells are most likely to spread from the primary tumour. Sometimes there is more than one sentinel node. The Sentinel Lymph Node Biopsy (SLNB) is a procedure carried out to identify the sentinel lymph node(s) in the breast, so that they can be removed and examined to determine whether cancer cells have spread to them from the main tumour.

How does the SLNB procedure work?

A patient undergoing a Sentinel Lymph Node Biopsy will be injected with a very small dose of radioactive substance and a blue dye near to the nipple; these then enter into the lymphatic channels that subsequently drain into the local lymph nodes. The surgeon will then make a small cut in the armpit and identify the sentinel lymph nodes using a scanning device that detects radioactivity, and remove any lymph nodes that show traces of radioactivity or blue staining from the dye. These lymph nodes are then examined by a pathologist under the microscope for the presence of cancer cells. If cancer cells are found to be present then the surgeon may need to remove further lymph nodes, usually as a follow-up surgical procedure.

What are the benefits of SLNB?

SLNB is beneficial to patient for a number of reasons; in addition to helping doctors 'stage' cancers by identifying which cancers have spread to the lymph nodes, it is also fundamental in avoiding more extensive lymph node surgery. All lymph node surgery can lead to problems with lymph fluid drainage, causing swelling or lymphoedema, and the risk is reduced when fewer lymph nodes are removed.

Are there any risks to SLNB?

As SLNB involve less extensive surgery and removal of fewer lymph nodes than standard lymph node surgery, there is a lower potential for adverse effects or harm. Similar to other surgical procedures, SLNB can cause short-term pain, swelling and bruising at the surgical site; there is a small risk of infection in the wound. Rarely patients can have an allergic reaction to the blue dye used in SLNB. All risks will be discussed in full with patients by the treating consultant prior to the procedure.


Content reviewed: October 2014
