This page has been written as a guide for anyone thinking about having a sentinel lymph node biopsy for melanoma. Your healthcare team will give you more details, and answer any questions or address any concerns you may have.
What is a sentinel lymph node biopsy?
The lymphatic system is a network of vessels that carry clear fluid called lymph around the body. Lymph vessels lead to lymph nodes that are found in the neck, armpit, groin, chest, and abdomen (tummy).
The first lymph node in the chain that receives lymph fluid from a particular area of the body is called the sentinel node. Any cancer cells from melanoma can move through the lymph vessels to the sentinel node where they might get trapped and may start growing. If this happens the node will swell and can be felt. In the early stages, when there are relatively few cancer cells, the lymph node cannot be felt through the skin. A sentinel node biopsy is one way to check the stage of your melanoma.
The sentinel node is removed during surgery and looked at under a microscope to see if the cancer has spread.
The surgery to remove the sentinel node will be done at the same time as the wider local excision (where the healthy tissue around the melanoma is removed). The surgery is usually done using general anaesthesia (you will be asleep), and you will go home the same day.
Why do I need a sentinel lymph node biopsy?
Biopsy is the only reliable method to find out if the melanoma has spread to the lymph node when the melanoma is first detected.
If the biopsy does not show melanoma cancer cells in the node, it usually means the cancer has not spread, and the chance of it coming back is low. This gives most people a sense of reassurance and relief.
If the biopsy does show melanoma cancer cells, your medical care will be discussed at the Multidisciplinary Team (MDT) meeting and further treatment may be suggested. There are various options available.
A sentinel lymph node biopsy is used for diagnosis, and there is no strong evidence to suggest the procedure helps improve your health. It helps us to find out the stage of cancer.
Should I have a sentinel lymph node biopsy?
The decision is yours. If we think this test is useful in your case, your specialist will discuss the procedure and its side effects in detail with you.
You will be able to take as much time to get the information you need to make an informed decision about whether you would like the procedure.
Possible advantages of a sentinel lymph node biopsy
- It helps to find out whether cancer has spread to the lymph node. It is better than ultrasound scans at finding very small cancers in the lymph node.
- It can help predict what might happen in the future.
- People who have had the operation may be able to take part in clinical trials of new treatments for melanoma. These trials often cannot accept people who have not had this operation.
- If you have a positive sentinel lymph node biopsy you may now be eligible for certain cancer treatments, in the form of drugs/medications.
Possible disadvantages of a sentinel lymph node biopsy
- It does not to cure the cancer. There is no strong evidence that people who have the operation live longer than people who do not have it.
- The result needs to be interpreted carefully. Out of every 100 people who have a negative sentinel lymph node biopsy, around 3 might still have cancer return in the same group of lymph nodes.
- A general anaesthesia is needed for the operation.
- You may have complications because of the operation.
How is a sentinel lymph node biopsy done?
- On the day of surgery before your operation, a small amount of radioactive tracer is injected near the primary melanoma scar (where the first skin cancer was). The radiation dose from this is very low, like a spinal X-ray.
- You are positioned under the scanner. The tracer moves from the melanoma site to the lymph node. This is recorded by the scanner.
- The first node to take up the tracer is the sentinel node - there may be more than one.
- Later that same day, you will have the operation to remove the sentinel lymph node. You will be a given a general anaesthesia so you will be asleep.
- While you are asleep, a blue dye is injected into the area of the primary melanoma. The dye travels through the lymph vessels and is taken up by the sentinel node. The blue colour of the node/nodes helps to find them.
- The node/nodes are removed through a small cut in the skin in the area that was marked during the scan.
- The wider excision of the primary melanoma is also done during this operation.
- The removed node/nodes are looked at under a microscope by a histopathologist. It takes about three weeks for the results to come back.
What happens after the sentinel lymph node biopsy?
After your surgery you might have some slight pain, but this can controlled with mild painkillers such as paracetamol and ibuprofen.
You may feel tired and should take it easy for about a week.
You can drive once you feel safe to do so - for most people this is about two weeks.
If you need a fit note please ask. You will be able to work again once you feel ready. Once the lab report (histology) is ready you will be told the results.
Further support and information
NGS Macmillan Wellbeing Centre
Southmead Hospital, Bristol, BS10 5NB
The centre offers ‘drop ins’ for coffee and a chat or appointments for specific needs.
Opening times: Monday to Friday 08:30 - 16:15.
Phone number: 0117 414 7051
Skin Cancer Research Fund (SCaRF)
Based at Southmead Hospital
Phone: 0117 414 8755
ScaRF
Macmillan Cancer Support
Practical advice and support for cancer patients, their families, and carers.
Macmillan Cancer Support | The UK's leading cancer care charity
Phone: 0808 800 1234
How to contact us
Skin Cancer Nurse Specialists
0117 414 7415
skincancercns@nbt.nhs.uk
Cancer Support Worker
Claire Williams
0117 414 7615
© North Bristol NHS Trust. This edition published January 2025. Review due January 2028. NBT002935
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