Sentinel node biopsy (SNB)

What is the sentinel node (SN)?

The sentinel lymph node (gland) is the first lymph node in your armpit to which breast cancer can spread. It is one of the lymph nodes, that are small round organs that are part of the body’s lymphatic system.

What is a sentinel node biopsy (SNB)?

A sentinel lymph node biopsy is a way of finding out whether cancer cells have spread in to any of the lymph nodes under your arm.

How is a sentinel node biopsy taken?

Before your breast cancer surgery, you will need to go to the Nuclear Medicine Department where you will have a small amount of mildly radioactive liquid injected in to your breast. The radioactive liquid is called a tracer. Later during your surgery, your surgeon will also inject a small amount of blue dye in to your breast. The radioactive liquid and the dye drain away from the breast tissue in to 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) which are then sent to the laboratory to see if they contain cancer cells.

Why have I been recommended for a sentinel node biopsy?

By removing the sentinel lymph node, we can find out whether your breast cancer has or has not spread to your armpit nodes. This important information helps us to advise you about the stage of your cancer and the best type of breast cancer treatment for you.

What are the benefits of SNB in comparison to removing all the nodes?

• Less discomfort and early mobility in your shoulder / arm.

• Reduced risk of lymphoedema (swelling of your arm).

• Shorter hospital stay and a quicker overall recovery.

What are the disadvantages of SNB?

• Blue dye will discolour your urine, stools, contact lenses (please remove before surgery), and tears for a few days following your surgery. Your breast skin will be discoloured for up to a few months and very occasionally a year or so.

• Allergic reaction to the blue dye can rarely happen whilst under the anaesthetic and within one hour of surgery. This can be treated but can (very rarely) be severe.

• Injection of radioactivity in to your breast may give slight discomfort.

What are the side effects of armpit surgery?

For some patients, armpit node removal can cause temporary shoulder stiffness, nerve pain, and / or permanent lymphoedema.

The side effects of armpit surgery increase with the number of nodes removed. This means if we remove only the SN side effects are less than traditional armpit surgery, where several lymph nodes are removed.

Will the procedure hurt?

You will have a general anaesthetic, so you will be asleep during the procedure. You may have slight discomfort after the procedure and should take mild painkillers (such as paracetamol) as discussed with your surgeon or breast care nurse.

How long will I have to stay in hospital?

You may have your surgery as a day case, or stay longer as an inpatient if you are having another procedure.

What will happen before my surgery?

Your breast care nurse will have already explained the procedure to you, but you will have further opportunities to ask questions in the Nuclear Medicine Department and with your surgeon when signing your consent form. Please remember you can withdraw your consent for treatment at any time.

What if we cannot find the sentinel nodes?

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

When can I drive again?

You should not drive immediately after your surgery, so you will need someone to take you home. You should discuss with your breast care nurse or surgeon when you will be able to drive after surgery.

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

Your wound is covered with a water-resistant dressing and should be removed within five to seven days (either by you, your GP practice nurse, or district nurse). This will be discussed and agreed with you before you leave hospital.

You may also have steri-strips, which should be kept in place for up to 10 days. You can have a bath or shower immediately but do not soak your wound for five days.

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

The pathologist examines the SN under the microscope and your results should be available in a couple of weeks. Your surgeon will give you your test results on the sentinel node two to three weeks after your SNB procedure.

If the SN contains cancer cells it is possible further cancerous nodes are still present in your armpit (this happens in around 20 to 25% of cases). For this reason you will need 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 the lab finds that none of the lymph nodes contain cancer cells, you will not need to have any more nodes removed.

Further information

Further information on cording (which are changes to some of the lymphatic vessels) and the risk of lymphoedema can be found in the Breast Cancer Care booklet Your operation and recovery.

If you have any further questions about this procedure, please either speak to the healthcare professional responsible for your care or phone your breast care nurse via the Cancer Co-ordinator Line on 01227 868666.