Sentinel Node Biopsy for Melanoma
What is a Sentinel Node Biopsy?
Sentinel node biopsy is a surgical procedure that removes the first lymph node(s) that your melanoma could spread to. It is an investigative test. By removing this first node, we can find out if melanoma has spread to the lymph nodes or not. Lymph nodes are the glands that filter bacteria and cancer cells from the body. They are commonly found in the neck, armpit and groin.
The result gives us important information about the stage of your melanoma, the prognosis, the monitoring scans that should be done and what treatment is recommended.
The sentinel lymph node biopsy is usually performed at the same time as the wide local excision (WLE) of your melanoma under general anaesthetic.
The result of the procedure will let us know if the melanoma has spread to the lymph nodes or not.
Sentinel node positive = melanoma has spread to the lymph nodes
Sentinel node negative = melanoma has not spread to the lymph nodes
How do we find the Sentinel Node?
Before surgery, a scan is performed in the radiology department. A small amount of isotope is injected around the melanoma scar. This isotope travels to the sentinel node. A scan finds where the sentinel node is and it is marked on your skin.This does not mean the sentinel node is positive. It only means that we have found where the sentinel node is.
Under general anaesthetic, your surgeon will find the sentinel node that has been marked by the scan. They will use the isotope that has been injected and blue dye. This takes approximately 60 minutes.
Rarely, despite the scan and blue dye, no lymph node can be found and the test is abandoned.
The lymph node is sent to the lab to be analysed to find out if it has melanoma in it or not. We will only know if the lymph node is positive for melanoma when the result comes back from the lab. This can take two weeks.
What happens if the sentinel lymph node is positive?
A positive result means melanoma cells have been found in the lymph node. This means you have stage 3 melanoma.
Your surgeon will discuss further treatment options with you including further surgery or immunotherapy. A positive result will change the frequency and types of surveillance scans that are scheduled for you.
Should I have a sentinel node biopsy?
A sentinel node biopsy is an optional operation to find out more information about your melanoma prognosis. Your surgeon will discuss at length the pros and cons of a sentinel node biopsy. It depends what type of melanoma you have as sentinel node biopsy is not advised for all melanomas. It also depends on how much information you would like on your prognosis and what further treatment you would avail of should the biopsy be positive.