Axillary Lymph Node Surgery – Axillary Lymph Node Clearance and Sentinel Lymph Node Biopsy

Why do the lymph nodes need to be biopsied?

When breast cancers begin to spread around the body (metastasize) they first spread to the lymph nodes around the breast. A breast cancer cell can enter into the lymphatic channels that drain your breast and end up in the regional lymph nodes. The most common site of lymph nodes that your breasts drain to is in the axilla (arm pit). Less commonly the cancer cells can spread to lymph nodes between the ribs (internal mammary chain), the neck (supraclavicular lymph nodes and even to the other breast and axilla (contralateral).

It is important that we obtain determine whether the cancer has spread to lymph nodes or not. If the cancer has spreads to the lymph nodes then your treatment after surgery (adjuvant therapy) will likely be more aggressive including Chemotherapy and hormonal therapy.

What is a sentinel Node?

The sentinel Lymph Node is the first lymph node that a breast cancer within the breast will drain to. This is the most likely lymph node to have cancer in it if the cancer has begun to spread.

Most common location is in the axilla (arm pit) on the same side of the breast cancer. Other sites can be between the ribs (internal mammary), in the neck (supraclavicular fossa) or in the other breast and axilla (contralateral).

Prior to the early 1990’s every patient who had a breast cancer underwent an axillary clearance. On average approximately 40% 0f all women with breast cancer will have cancer within the lymph nodes. This means that the other 60% of women had an axillary clearance with the associated risk of lymphedema for no benefit. This prompted the development of sentinel node biopsy for breast cancer. The sentinel node biopsy allows only the most likely lymph node to have cancer in it to be removed and only then if cancer is found an axillary clearance is performed.

Over 80% of women are eligible for a sentinel node biopsy. This allows on average 60% of women who do not have cancer in the lymph nodes to avoid axillary clearance and its associated lymphedema risk

How is the sentinel node located and removed

To find the sentinel lymph node we use a combination of three methods:


This is an injection of a small amount of radioactive tracer in to the breast prior to the surgery. The tracer is taken up in the lymph channels and drains to the sentinel node. A scan is taken to show the surgeon where it is in the body and how many (there an be 2 or 3 sentinel nodes). During the surgery a ‘Gammo Probe’ is used to locate the node. The probe detects the radioactive tracer and beeps when it comes close to the Sentinel lymph node


This identifies lymph nodes that receive drainage form a breast cancer. Figure 1: Axillary sentinel lymph nodes, Figure 2: A breast cancer draining to axillary sentinel node and internal mammary lymph nodes.


Blue dye injection

Once you’re asleep on the operating table a small amount of blue dye will be injected around your nipple. The blue dye travels in the lymph channels to the sentinel node and stains it bright blue. This creates a visual guide to the surgeon to find the sentinel node accurately and to be sure the correct node is removed. The blue dye will stain your skin for several weeks, but it will fade.

Can everyone have a sentinel node biopsy?

Sentinel Node Biopsy can be performed in the majority of patients (over 80%). Unfortunately not every person is suitable to have a sentinel node biopsy. The accuracy of a sentinel node biopsy has only been conformed in patients with cancers that have particular characteristics.

The sentinel node biopsy is performed as a ‘snap shot’ of you axillary lymph nodes to see if they have cancer present in them. If it is discovered that your lymph nodes already have cancer in them at the time of diagnosis then a sentinel node biopsy will be of no benefit and you will require an axillary dissection.

The criteria to having a sentinel node biopsy include:

  • No known cancer involving the axillary lymph nodes.
  • Small tumours less than 3cm.
  • Cancer not involving multiple different spots within the breast.
  • No previous axillary surgery.

If your tumour is greater than 3cm the accuracy is unknown. You may be offered to be part of the SNAC-2 study that is looking into the accuracy of sentinel node biopsy in larger tumours. Here you may be randomly allocated into the sentinel node group or into the axillary clearance group. If you have a tumour greater than 3cm and are not part of this study you will need an axillary clearance at the initial operation. Dr. green will discuss this with you in detail if you are eligible for the SNAC-2 study.

Size of Cancer deposit within the sentinel lymph node

What does this mean?


0 – 0.2mm
In Transit Cells

Regarded as a negative sentinel node. These cancer cells will be destroyed by the immune system.

No further axillary surgery.

0.21 – 2mm
Micro metastasis

Controversial amongst breast surgeons.

May require axillary clearance but will depend on the cancer type – case by case decision.

Greater than 2mm
Macro metastasis

Positive sentinel node meaning that there is the possibility of additional cancerous lymph nodes within the axilla.

Axillary Clearance is currently recommended.

What happens if the sentinel node has cancer in it?

If the sentinel node biopsy reveals the presence of cancer cells within, it is most likely that a completion axillary clearance will be recommended.

The evidence for an axillary dissection with a positive sentinel lymph node is changing all the time and creates a significant amount of controversy amongst breast surgeons around the world. There is some, but not conclusive evidence that not all patients with a positive sentinel lymph node need a completion axillary clearance. The need for an axillary clearance will depend on the size of the cancer cells within the lymph node and the particular make up of your cancer type.

Below is a very general guide to who requires a completion axillary clearance. Dr. Green is keeping up to date with the emerging world trends in regards to Axillary surgery and is happy to discuss these with you at the time of your consultation. As criteria change the information below will change to suite.

What is intraoperative assessment of the sentinel lymph node

Whilst you a are asleep for your operation the sentinel lymph node will undergo a preliminary snap shot assessment by a pathologist. The node will be divided a smear of cells will be checked under the microscope. If the sentinel node has cancer within it the pathologist may be able to detect this whilst you are asleep. If this is the case we will then proceed with an axillary clearance. This will avoid the need for a second operation later. This procedure is called ‘Touch inprint Cytology’.

It is important to understand that a negative preliminary sentinel node result is promising, but does NOT guarantee the final result will be negative and an axillary clearance may be indicated at a second operation. If the preliminary result is negative the node will undergo a thorough examination under the microscope. This takes 1-2 days to complete. It is possible that a negative intraoperative lymph node may finally be shown to have cancer cells within it. This will be discussed with you at your post-operative visit and may require a second operation to perform an axillary lymph node clearance.

Why is an Axillary Lymph Node Clearance required?

When a breast cancer spreads, it usually does so by moving in the lymph fluid from the breast. The cancer cells will travel in the lymph channels from the breast towards the axilla (arm pit) where they will first be trapped by the Lymph Nodes. Most cancer cells are destroyed here, although eventually they develop the ability to spread further into the blood stream and around the rest of the body.

An axillary clearance is required when it has been proven that cancer cells have spread to the lymph nodes. This may be known at the time of surgery or most commonly after a sentinel lymph node biopsy has been performed.

The aim of the surgery is remove all the lymph nodes in the axilla that drain the breast and leave all the other lymph nodes that drain the arm behind. This allows all cancer that has spread to the axilla to be removed and reduce the chance of the cancer recurring in the axilla (axillary recurrence).

Important decisions about your treatment will be made on the number of lymph nodes removed and how many have become involved with cancer.

What is an axillary clearance?

Axillary Lymph Node Clearance involves removal of all the lymph nodes in the axilla (arm pit) that a breast cancer may have spread to.

There are hundreds of lymph nodes in the body and an axillary lymph node clearance aims to remove only those lymph nodes responsible for the breast. Closely associated to the axillary lymph nodes are lymph nodes that receive lymph fluid from the arm. It is aimed to leave all of these lymph nodes behind.

The surgery involves an incision up under the armpit and is performed under a general anesthetic with a hospital stay of one or two nights.

After the lymph nodes are removed a lot of fluid can build up. To avoid this happening a drain will be placed. You will go home with a drain in place. The nursing staff will teach you how to look after the drain and to record the amount coming out. Once the amount of fluid being produced is low enough the drain will be removed.

How many lymph nodes will be removed?

All of the lymph nodes involving the breast in the axilla will be removes. The number of lymph nodes varies from person to person. On average over 20 lymph nodes will be removed although this number may vary from 10-40.

The lymph nodes draining the arm will be left behind so as to reduce the likelihood of lymphedema (swelling of the arm).

What are the possible complications that can occur form axillary surgery?

Common Uncommon (up to 2% cases) Rare but important (less than 1% of cases)
  1. Seroma formation (15%).
  2. Need for a completion axillary dissection (2nd operation) – 15%.
  3. Numb patch of skin on the upper arm after axillary dissection (90%).
  4. Mild lymphedema (20%).
  5. Severe lymphedema needing pressure garments (7%).
  1. Wound infection.
  2. Bleeding requiring second operation to control.
  3. Painful patch of skin on upper arm.
  4. Keloid (lumpy) scarring
  1. Death from anesthetic.
  2. DVT / PE - blood clots in legs or arms.
  3. Heart attack.
  4. Stroke.
  5. Allergic reaction.