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Sentinel lymph node biopsy (SLNB)

Published by Bupa's health information team, November 2008.

This factsheet is for people who are planning to have a sentinel lymph node biopsy (SLNB), or who would like information about it.

Lymph nodes are small kidney bean-shaped organs that are part of your natural defence system and are often referred to as 'the glands'. They are located throughout the body particularly in the armpits, neck and groin. They filter fluid that travels through them, removing any dying cells and bacteria. SLNB helps identify the first lymph node that tumour cells drain into and it's removed and tested for cancer.

Your care will be adapted to meet your individual needs and may differ from what is described here. So it's important that you follow your surgeon's advice.

About SLNB
Preparing for SLNB
About the procedure
What to expect afterwards
Recovering from SLNB
What are the risks?
Questions and answers
Related topics
Sources

About SLNB

If you have been diagnosed with cancer, to help plan appropriate treatment, your doctor will need to know if the cancer has spread to the lymph nodes. SLNB involves using a radioactive isotope and/or a blue dye to find the first lymph node (the 'sentinel' node) that the cancer drains into. The sentinel node is removed and examined in the laboratory for cancer cells (sometimes more than one node is removed).

If cancer cells are found in the sentinel node, further surgery to remove all the lymph nodes (lymphadenectomy) may be needed. If cancer cells are not found, it means the cancer hasn't spread to the lymph nodes and you are spared unnecessary treatment.

Preparing for SLNB

Your surgeon will explain how to prepare for SLNB. For example, if you smoke, you will be asked to stop as smoking increases your risk of getting a chest and wound infection, which can slow your recovery.

SLNB is usually done as a day-case procedure. This means you have the procedure and go home the same day. Sometimes, if you are having a tumour removed at the same time, you may need to stay in hospital overnight.

SLNB may be done under general or local anaesthesia. Under general anaesthesia, you will be asleep during the procedure. Local anaesthesia completely blocks feeling from the biopsy area and you will stay awake. You may be offered a sedative with a local anaesthetic to help you relax during the procedure. Your surgeon and anaesthetist will discuss which type of anaesthesia is most suitable for you.

For local anaesthesia there is no need to go without food and drink. If you are having a general anaesthetic, you will be asked to follow fasting instructions. Typically you must not eat or drink for about six hours before a general anaesthetic. However, some anaesthetists allow occasional sips of water until two hours beforehand.

At the hospital your nurse may check your heart rate and blood pressure, and test your urine.

Your surgeon will explain the procedure and ask you to sign a consent form. This confirms that you understand the risks, benefits and possible alternatives to the procedure and have given your permission for it to go ahead.

About the procedure

Blue dye is used either alone, or in combination with the radioactive isotope. If a radioactive isotope is used, the procedure is done in three stages.

Lymphatic mapping

If a radioactive isotope is used, you will be taken to the nuclear medicine department in the hospital. You don't need anaesthetic for lymphatic mapping.

You will be asked to lie on a table in the imaging room. Your radiologist (a doctor specialising in imaging methods to diagnose medical conditions) will inject a small amount of a radioactive isotope around the tumour. The isotope drains into nearby lymph nodes. The lymph node area is located using a scanner or a special gamma sensor and marked on your skin. Your radiologist may take X-ray pictures to show the location of the sentinel node(s).

You will return to your room or the day-care ward and wait for one hour.

Intradermal blue dye injection

This is usually done in the operating theatre after the local or general anaesthetic has taken effect. The blue dye is injected into the skin close to the tumour. The dye drains into the lymph nodes. Your surgeon will allow three to 10 minutes for the dye to reach the sentinel lymph node(s) and then begin the biopsy.

Sentinel node biopsy

The biopsy procedure usually takes 30 minutes. A cut is made into the skin and soft tissues to reach the lymph node area.

Your surgeon will follow the blue dye pathway to locate the sentinel lymph node(s). If a radioactive isotope is used your surgeon will also use the X-ray picture and a hand-held gamma sensor to identify the sentinel node(s).

The affected sentinel node(s) are removed and sent to a laboratory for testing. The skin cut is closed with dissolvable stitches.

What to expect afterwards

If you have general anaesthesia, you will need to rest until the effects of the anaesthetic have passed. You may need pain relief to help with any discomfort as the anaesthetic wears off.

After a local anaesthetic it may take several hours before the feeling comes back into the biopsy area. Take special care not to bump or knock the area.

You will have a dressing covering your biopsy area. This is usually removed on the second day. Dissolvable stitches will disappear on their own in seven to 10 days.

You will need to arrange for someone to drive you home. You should try to have a friend or relative stay with you for the first 24 hours.

Your nurse will give you some advice about caring for your healing wounds before you go home. You may be given a date for a follow-up appointment.

Results

Your results will be ready several days later and will usually be sent in a report to the doctor who requested your biopsy. Your doctor will review the results and discuss them with you at your follow-up appointment.

Recovering from SLNB

If you need pain relief, you can take over-the-counter painkillers such as paracetamol or ibuprofen. Always read the patient information that comes with your medicine and if you have any questions, ask your pharmacist for advice.

General anaesthesia (and sedation) temporarily affects your coordination and reasoning skills, so you must not drive, drink alcohol, operate machinery or sign legal documents for 48 hours afterwards (or 24 hours after sedation). If you are in any doubt about driving, please contact your motor insurer so that you are aware of their recommendations, and always follow your surgeon's advice.

The blue dye usually flushes out in the urine making it green in colour. This is normal and nothing to worry about. The injection area may remain blue for up to six months.

What are the risks?

SLNB is commonly performed and generally safe. However, in order to make an informed decision and give your consent, you need to be aware of the possible side-effects and the risk of complications of this procedure.

Side-effects

These are the unwanted but mostly temporary effects of a successful procedure, for example feeling sick as a result of the general anaesthetic.

Common side-effects of SLNB include pain, swelling and bruising in the biopsy area. These should settle within a day or two.

Complications

This is when problems occur during or after the procedure. Most people are not affected. The possible complications of any operation include an unexpected reaction to the anaesthetic, infection, excessive bleeding or developing a blood clot, usually in a vein in the leg (deep vein thrombosis, DVT).

Specific complications of SLNB are uncommon but can include:

allergic reaction to the blue dye - medicines are available to treat an allergic reaction
infection - you may need antibiotics
build up of fluid in nearby tissues (lymphoedema) or the in lymph node area (seroma) - you may need to have the fluid drained

The exact risks are specific to you and differ for every person, so we have not included statistics here. Ask your surgeon to explain how these risks apply to you.