Surgery to the lymph nodes for breast cancer

There are different types of lymph node surgery. Your surgeon may remove some or all the lymph nodes in your armpit to check them for invasive breast cancer cells.

What is surgery to the lymph nodes?

Your surgeon may remove some or all the lymph nodes in your armpit to check them for cancer cells. This can also:

  • remove any lymph nodes that contain cancer cells
  • give information about the stage of the cancer.

There are different types of lymph node surgery. You may need more treatment if only some lymph nodes were removed.

Sentinel lymph node biopsy (SLNB)

A sentinel lymph node biopsy (SLNB) is a way of checking the lymph nodes in the armpit. The lymph nodes most likely to have cancer cells are called the sentinel lymph nodes. These are the first ones that lymph fluid drains to from the breast area.

Your surgeon or nurse will explain if an SLNB is an option for you.

You will have an SLNB if the ultrasound or fine needle aspiration of your armpit was normal.

During an SLNB, surgeons remove the smallest number of lymph nodes possible (usually 1 to 3). This reduces the risk of side effects that can happen after lymph node surgery. These include swelling (lymphoedema) of the arm and stiffness of the arm and shoulder.

If there are no cancer cells in the sentinel nodes, you will not need any further treatment to the lymph nodes.

If cancer cells are found in the sentinel nodes, your cancer doctor will talk to you about whether you need further treatment. You may be offered another operation to remove the remaining lymph nodes. Some people have radiotherapy to the remaining lymph nodes instead of more surgery.

In some hospitals, the sentinel nodes can be checked for cancer cells during the operation to remove the cancer. This means that if more lymph nodes need to be removed, it can be done during the same operation.

Having an SLNB

Before the sentinel lymph nodes can be removed, the surgeon needs to check which nodes are the sentinel lymph nodes.

Before the surgery, the surgeon injects a harmless amount of radioactive liquid into your breast. During the operation, they use a handheld machine to find the lymph nodes that have picked up the radioactive liquid. The surgeon may also inject a blue dye into your breast during the operation. This stains the sentinel lymph nodes blue. The lymph nodes that pick up the radioactive liquid or become blue first are the sentinel lymph nodes.

The surgeon can then remove the blue or radioactive nodes (sentinel nodes). These are tested to see if there are any cancer cells in them.

Other ways to find sentinel nodes

Some people have their sentinel nodes detected using a magnetic tracer. The magnetic tracer is a liquid containing tiny iron particles. It is injected into the breast tissue, where it is absorbed by the lymph vessels and sentinel nodes. A doctor or nurse can then use a magnetic probe to detect the sentinel nodes. Your doctor or nurse can explain more about magnetic tracers.

Removing all the lymph nodes

Sometimes the surgeon will recommend removing all the lymph nodes in the armpit. This is called an axillary lymph node dissection (ALND) or axillary lymph node clearance (ANC). It aims to remove any nodes that contain cancer cells in the area close to the cancer.

You usually have an ALND if:

  • a fine needle aspiration or biopsy of the lymph nodes finds cancer cells
  • an SLNB or sample of the lymph nodes shows cancer cells in the lymph nodes.

An ALND increases the risk of swelling of the arm. This is called lymphoedema. We have more information about lymphoedema and taking care of your arm.

Related pages

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Dr Rebecca Roylance, Consultant Medical Oncologist and Professor Mike Dixon, Professor of Surgery and Consultant Breast Surgeon.

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Date reviewed

Reviewed: 01 October 2023
Next review: 01 October 2026
Trusted Information Creator - Patient Information Forum
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