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Sentinel Node Biopsy

When performing breast cancer surgery, it is important to know if the disease has spread to the lymph nodes. The axillary lymph nodes (arm pit) are the most common path for lymph node spread. Axillary surgery and management have changed over the years and is individualised to each patient.

What is a sentinel lymph node biopsy?

The sentinel node is the first draining lymph node in a group of nodes. The principle of a sentinel node biopsy is that if there is no cancer in the sentinel node (1st check point), there is no cancer in the other lymph nodes.

The operation is usually performed at the same time as the breast cancer operation. I use two types of tracers to find the sentinel node: Technitium 99 and blue dye. On the morning of surgery, you will have a radioactive dye (Technetium 99) injected in the breast. A scan is used to locate and mark the node. At the start of the operation when you are asleep, I will inject some blue dye under the skin of the breast. A special radioactive detecting probe (gamma probe) helps find the sentinel node. The blue dye acts a visual guide to find the node(s).

What are the risks for a sentinel node biopsy?

Sentinel node biopsy is a very low risk procedure. Common complications are bleeding, fluid collection (seroma) and pain. The risk of lymphoedema is incredibly low, which is one of the reasons why we prefer this method. It is approximately 5% or less for sentinel node biopsy, whilst an axillary clearance (most of the nodes taken) is 20-30%. The most serious complication is anaphylaxis (severe allergic reaction) to the blue dye. This risk is 1 in 1,000. If it happens you will already be under anaesthesia but may require a longer stay in hospital for monitoring.