Sentinel lymph node biopsy (SNB)

You have been referred to the hospital for a sentinel lymph node biopsy. This leaflet will explain the following.

• What a sentinel lymph node biopsy is.

• How the biopsy is taken.

• What the benefits and disadvantages are to having the biopsy.

• What happens during and after the biopsy.

We hope this leaflet answers some of the questions you may have. If you have any further questions or concerns, please speak to a member of your healthcare team.

What is a sentinel lymph node?

Sentinel lymph nodes (glands) are the first few lymph nodes in your armpit to where lymphatic fluid from the breast moves.

What is a sentinel lymph node biopsy?

A sentinel lymph node biopsy can find out whether cancer cells have spread into any of the lymph nodes under your arm.

How is the biopsy taken?

Before your breast cancer surgery, you will need to go to the Nuclear Medicine Department. Here a small amount of mildly radioactive liquid is injected into your breast. The radioactive liquid is called a tracer.

Later during your surgery, your surgeon will inject a small amount of blue dye into your breast. The radioactive liquid and dye drain from your breast tissue into the lymph glands nearest to your breast.

Your surgeon will be able to identify the sentinel lymph node with a small radioactive probe. These are the sentinel nodes. The surgeon usually removes one to two nodes (but it can be up to four). The nodes are then sent to the laboratory to see if they contain cancer cells.

Why have I been recommended for this biopsy?

By removing the sentinel lymph node, we can find out whether your breast cancer has spread to your armpit nodes. This information is important, as it helps us to advise you on:

• the stage of your cancer; and

• the best type of breast cancer treatment for you.

What are the benefits of having this biopsy compared to removing all my nodes?

• You will have less discomfort after surgery. You will be able to move your shoulder / arm earlier.

• There is a reduced risk of lymphoedema (swelling of your arm).

• You will have a shorter hospital stay and quicker overall recovery.

What are the disadvantages to having a sentinel lymph node biopsy?

• For a few days following your surgery, the blue dye will discolour your:

  • urine (pee)

  • stools (poo)

  • contact lenses

  • tears

  Please remove your contact lenses before surgery.

• Your breast skin will be discoloured for up to a few months, and very occasionally longer.

• Rarely, some patients have an allergic reaction to the blue dye whilst under the anaesthetic and within one hour of surgery. This can be treated, but very rarely it can be severe.

• The injection of radioactivity into your breast may cause slight discomfort.

What are the side effects of armpit surgery?

For some patients, removing their armpit node can cause:

• shoulder stiffness

• nerve pain

• permanent lymphoedema

The side effects of armpit surgery increase with the number of nodes removed. If we only remove the sentinel node, the side effects are less than if you have traditional armpit surgery. During traditional armpit surgery we remove several lymph nodes.

Will the procedure hurt?

You will have a general anaesthetic for this procedure, so you will be asleep.

You may have slight discomfort after the procedure. To help with this, take mild painkillers (such as paracetamol) as discussed with your surgeon or breast care nurse.

How long will I stay in hospital?

You may have your surgery as a day case, so you can go home afterwards.

If you are having another procedure, you may need to stay in hospital as an inpatient.

What will happen before my surgery?

Please ask any further questions while in the Nuclear Medicine Department. Before your procedure your surgeon will ask you to sign a consent form.

Why do I need to sign a consent form?

All patients must give permission before they receive any type of medical treatment, test, or examination. Consent is usually given when you sign the consent form before your treatment, but we may ask you to give it verbally. 

• You must give your consent voluntarily.

• The hospital must give you all the information you need to make a decision about your treatment. This is so you can give us informed consent.  If you have not been given this information, or you have but you still have questions, please speak to a member of staff. 

• You must be capable of giving consent. This means that you understand the information given to you and can make an informed decision.

When we ask you to give consent, please use this time to ask any questions you may still have. For more information, please go to the NHS Consent for Treatment web page. Remember, you can withdraw your consent for treatment at any time.

What if my surgeon cannot find the sentinel nodes?

Occasionally it is not possible to find the sentinel node(s). If this happens your surgeon will examine your axilla (armpit). They will take a few node(s) which is likely to represent the sentinel node.

When can I drive again?

Do not drive immediately after your surgery. Arrange for someone to take you home from hospital. Speak to your breast care nurse or surgeon about when you can drive again after surgery.

How do I care for my wound when I get home?

Your surgeon will cover your wound with a water-resistant dressing. Remove this dressing 5 to 7 days after your surgery. You can do this, or you can ask your GP practice nurse or district nurse. Your breast care nurse will discuss and agree this with you before you leave hospital.

You may also have steri-strips. Keep these in place for up to 10 days.

You can have a bath or shower after surgery, but do not soak your wound for 5 days.

When will I get my results? Will I need further procedures?

A pathologist will examine your sentinel node in a laboratory. Your surgeon will give you your test results 2 to 3 weeks after your procedure.

If your sentinel node contains cancer cells it is possible further cancerous nodes are still in your armpit. This happens in around 20 to 25% of cases. For this reason, you will need to discuss with your surgeon either:

• further armpit surgery to remove as many of the remaining lymph nodes as possible; or

• you may be offered radiotherapy to your armpit.

If none of your lymph nodes contain cancer cells, you will not need to have any more nodes removed.

What if I have any questions or concerns?

If you have any further questions about your biopsy, please either:

• speak to the healthcare professional responsible for your care; or

• phone your breast care nurse via the Cancer Care Line on 01227 868666.

Further information

• Breast Cancer Care. Your operation and recovery (BCC151).

  This booklet includes information on cording and the risk of lymphoedema. Cording is changes to some of the lymphatic vessels.

Ask 3 Questions

There may be choices to make about your healthcare. Before making any decisions, make sure you get the answers to these three questions:

• What are my choices?

• What is good and bad about each choice?

• How do I get support to help me make a decision that is right for me?

Your healthcare team needs you to tell them what is important to you. It’s all about shared decision making.

What do you think of this leaflet?

We welcome feedback, whether positive or negative, as it helps us to improve our care and services.

If you would like to give us feedback about this leaflet, please fill in our short online survey. Either scan the QR code below, or use the web link. We do not record your personal information, unless you provide contact details and would like to talk to us some more.

If you would rather talk to someone instead of filling in a survey, please call the Patient Voice Team.

• Patient Voice Team
  Telephone: 01227 868605
  Email