Sentinel Lymph Node Biopsy

The first aim of axillary lymph node surgery is to provide an accurate assessment of whether tumour cells have spread from the primary tumour to these lymph nodes. This is performed by sentinel node biopsy. The assessment of whether the lymph nodes are negative or positive for tumour cells is the single most important factor in determining prognosis and planning additional (adjuvant) therapy following the surgery.

One of the most recent advances in breast cancer surgery has been the introduction of sentinel node biopsy where the first node, or group of nodes, is removed. Research has shown that if the sentinel node(s) are clear of tumour then the rest of the underarm nodes should also be clear. This is a much smaller operative procedure, with far less complications than axillary clearance, and is usually carried out through a separate incision under the arm at the same time as breast surgery. If a combined mastectomy and breast reconstruction is planned then the sentinel node biopsy is usually performed as a separate stand-alone procedure prior to the breast surgery.

The sentinel nodes will be detected in two different ways during your surgery:

Blue dye injection
A small amount of blue dye is injected close to the nipple under general anaesthetic. The blue dye travels through the lymphatic channels and reaches the first lymph node(s) under the arm very quickly.  The surgeon can trace these tiny blue lymphatic channels to the blue node or nodes. Injection of this dye is associated with a very small risk of an allergic reaction and in addition there can be some residual discolouration of the skin at the injection site.

Indocyanine green (ICG)
Recent research in Cambridge, Germany and Japan has now identified a new dye that is extremely safe and can be used to identify the sentinel nodes without any exposure to radiation. Indocyanine green (ICG), a fluorescent dye that is also injected under the nipple during surgery, can be seen passing through the lymphatic channels under the skin using a special infrared camera. This allows these lymphatics to be traced to the underarm area where the combination of blue dye and fluorescent dye allow the sentinel nodes to be detected and removed.
In those cases where the sentinel nodes have tumour cells within them an axillary clearance will be performed during a second operation.