What is breast cancer?

Breast cancer is a harmful growth that starts in the glandular tissue of your breast.

What is a lymph node?

Lymph nodes are small structures which lie along lymph vessels present throughout your body.

A sentinel node biopsy involves removing the sentinel nodes from your armpit. Sentinel nodes are the first lymph nodes in your armpit to which breast cancer cells may spread.

What are the benefits?

The cancer cells may have spread to your armpit.

The lymph nodes that your surgeon removes will be examined under a microscope to see whether they contain cancer. The result will help to decide on further treatment, without needing to remove all of the lymph nodes from your armpit.

Are there any alternatives?

If the lymph nodes in your armpit are found to contain cancer, the breast-care team may offer a procedure called axillary node clearance to remove all the lymph nodes under your arm.

Your breast-care team may offer surgery to remove a sample of the lymph nodes from your armpit (axillary node sampling).

What will happen if I decide not to have the procedure?

Your breast-care team may not be able to confirm if the cancer cells have spread to your armpit or recommend the best treatment for you.

What does the procedure involve?

You may be asked to come to hospital before your procedure for an injection into your breast. The injection contains a fluid (tracer) which travels to the sentinel nodes and becomes trapped there.

The procedure is performed under a general anaesthetic and usually takes 20 to 30 minutes.

During the procedure your surgeon may inject a blue dye into your breast. The dye travels to the sentinel node and stains it blue.

Your surgeon will make a cut in your armpit, below the area where hair grows.

Your surgeon will remove the nodes identified using the blue dye or tracer.

The lymph nodes that your surgeon removes will be examined under a microscope. Your surgeon will know the results 2 to 4 weeks later.

If cancer cells are found in the sentinel nodes it means the cancer may have spread to other lymph nodes in your armpit. Your breast-care team may recommend further treatment to your armpit, depending on how many of the sentinel nodes contain cancer.

What complications can happen?

Your breast-care team are trained to reduce the risk of complications.

Possible complications of this procedure are listed below. Some can be serious and may even cause death.

Any risk rates given are taken from studies of people who have had this procedure. Your doctor may be able to tell you if the risk of a complication is higher or lower for you. Some risks are higher if you are older, obese, have other health problems or you smoke. Health problems include diabetes, heart disease or lung disease.

General complications of any procedure

• Infection of the surgical wound. An infection usually settles with antibiotics and any pus may need to be removed. You may need another procedure.
• Allergic reaction to the equipment, materials or medication.
• Venous thromboembolism (VTE) — This is a blood clot in your leg (deep-vein thrombosis – DVT) or one that has moved to your lung (pulmonary embolus).
• Chest infection — your risk will be lower if you have stopped smoking and you are free of Covid-19 (coronavirus) symptoms for at least 7 weeks before the procedure.

Specific complications of this procedure

• Bleeding during or after the procedure.
• Developing a lump under your wound caused by fluid collecting (seroma).
• Developing a lump under your wound caused by blood collecting (haematoma). You may need another procedure to remove the blood.
• Numbness or continued pain around your armpit or the inner part of your arm. Any pain usually gets better within a few weeks. Numbness can last for up to 6 months and can sometimes be permanent.
• Swelling of your arm, hand or breast (lymphoedema). The risk is higher if you also have radiotherapy to your armpit or if most of your lymph nodes are removed. You can get lymphoedema months or even years later.
• Allergic reaction to the tracer. In very rare cases the allergic reaction can be severe.
• Discolouration of your urine, stools and tears for 1 to 2 days as a result of the blue dye used. The skin on your breast will be discoloured for a few weeks or months, and in very rare cases for a year or more.
• Sentinel node not found. If this happens, your surgeon will remove up to four lymph nodes so that they can be checked.
• Failure to find cancer cells, even if they are present in other lymph nodes in the armpit.
• Infection of the affected arm. After the procedure, you need to protect your hand and arm from possible infection.

Consequences of this procedure

• pain
• scarring of your skin

What happens after the procedure?

You should be able to go home the same day or the day after.

You should be able to build up to normal activities after 2 to 3 weeks.

Regular exercise should help you to return to normal activities as soon as possible. Before you start exercising, ask your breast-care team or your GP for advice.

Your breast-care team will arrange an appointment for you after surgery. The lymph nodes and any breast tissue that your surgeon removed will have been examined under a microscope. Your surgeon will tell you the results and discuss with you any treatment or follow-up care you need. They will also check your wound and be able to tell you when you can return to work.

Summary

Sentinel nodes are the first lymph nodes in your armpit to which breast cancer cells can spread. A biopsy to remove the sentinel nodes gives your breast-care team important information to help plan your future breast cancer treatment.

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