Display Patient Information Leaflets

Date issued: November 2025

Review date: November 2027

Leaflet section: Breast Care

PDF: Sentinel Lymph Node Biopsy.pdf [pdf] 143KB

West Devon and East Cornwall Breast Screening Service

You have been diagnosed with cancer of the breast. The breast tissue drains into lymph nodes or glands under the arm. At the moment, operations for breast cancer involve removing some or all of the glands (lymph nodes) from under the arm, as well as the breast tumour. We need to remove at least some of the glands to see if they contain cancer. The options are:

• A sentinel node biopsy (removes an average of 2 nodes)

• An axillary sampling (removes 4-6 glands)

• An axillary clearance (removes most or all of the gland - approximately 15-25 glands)

The glands are looked at to help plan further treatment. If the glands are affected by cancer, removing them is also part of your treatment.

What is a Sentinel Lymph Node?

In breast cancer, cells can break off from the breast lump. They travel along fine lymph channels to one lymph gland in the armpit and are held there for a time. The first node to receive cells from the breast is called the sentinel lymph node. 

An axillary sampling or axillary clearance operation does not specifically identify the sentinel node. A sentinel lymph node biopsy uses 2 special kinds of dye injected into the breast to find the most important node or nodes. Then our attention is directed to the gland most likely to contain spread from the tumour.

A recent study in the UK has shown the SLN biopsy is safe and accurate and that patients having this have fewer side effects from their surgery. The risks of arm swelling, arm discomfort and shoulder stiffness are all reduced with sentinel node surgery. The technique was developed in the USA and Europe and is used successfully around the world. 

What is involved?

A small amount of radioactive dye will be injected into the skin of your breast near the nipple 4-24 hours before your operation. Pictures will be taken of the breast and armpit using a special camera, which shows the radioactive dye. The radioactive fluid is carried along lymph vessels to the sentinel lymph node in the armpit, enabling the surgeon to find and remove this sentinel lymph node. 

The doctor will ask you to sign a consent form. This will state the operation you are having, and it is important that you understand it before signing. The side of your operation will be marked by an arrow with indelible pen. 
You will be asked by the doctor if you need to consent for any tissue/fluid samples to be used for evaluation purposes, research or quality control.

What are the Risks?

The amount of radiation involved is less than what you would have from a mammogram. No extra precautions are needed. The safety of the procedure will be monitored by the Radiation Protection Safety Officer. A fine needle is used to inject the radioactive dye. This may cause discomfort.

What if the Sentinel Node can’t be found?

Very rarely the SLN can’t be found. Pictures taken after the radioactive dye injection may suggest the sentinel node hasn’t taken up the dye. If this happens, your surgeon will discuss the options with you before your operation and ask for your permission to perform alternative surgery on the lymph glands.

You have been diagnosed with cancer of the breast. The breast tissue drains into lymph nodes or glands under the arm. At the moment, operations for breast cancer involve removing some or all of the glands (lymph nodes) from under the arm, as well as the breast tumour. We need to remove at least some of the glands to see if they contain cancer. The options are:

• A sentinel node biopsy (removes an average of 2 nodes)

• An axillary sampling (removes 4-6 glands)

• An axillary clearance (removes most or all of the gland - approximately 15-25 glands)

The glands are looked at to help plan further treatment. If the glands are affected by cancer, removing them is also part of your treatment. 

What is a Sentinel Lymph Node?

In breast cancer, cells can break off from the breast lump. They travel along fine lymph channels to one lymph gland in the armpit and are held there for a time. The first node to receive cells from the breast is called the sentinel lymph node. 

An axillary sampling or axillary clearance operation does not specifically identify the sentinel node. A sentinel lymph node biopsy uses 2 special kinds of dye injected into the breast to find the most important node or nodes. Then our attention is directed to the gland most likely to contain spread from the tumour.

A recent study in the UK has shown the SLN biopsy is safe and accurate and that patients having this have fewer side effects from their surgery. The risks of arm swelling, arm discomfort and shoulder stiffness are all reduced with sentinel node surgery. The technique was developed in the USA and Europe and is used successfully around the world. 

What is involved?

A small amount of radioactive dye will be injected into the skin of your breast near the nipple 4-24 hours before your operation. Pictures will be taken of the breast and armpit using a special camera, which shows the radioactive dye. The radioactive fluid is carried along lymph vessels to the sentinel lymph node in the armpit, enabling the surgeon to find and remove this sentinel lymph node. 

The doctor will ask you to sign a consent form. This will state the operation you are having, and it is important that you understand it before signing. The side of your operation will be marked by an arrow with indelible pen. 
You will be asked by the doctor if you need to consent for any tissue/fluid samples to be used for evaluation purposes, research or quality control. 

What are the Risks?

The amount of radiation involved is less than what you would have from a mammogram. No extra precautions are needed. The safety of the procedure will be monitored by the Radiation Protection Safety Officer. A fine needle is used to inject the radioactive dye. This may cause discomfort.

What if the Sentinel Node can’t be found?

Very rarely the SLN can’t be found. Pictures taken after the radioactive dye injection may suggest the sentinel node hasn’t taken up the dye. If this happens, your surgeon will discuss the options with you before your operation and ask for your permission to perform alternative surgery on the lymph glands.

You have been diagnosed with cancer of the breast. The breast tissue drains into lymph nodes or glands under the arm. At the moment, operations for breast cancer involve removing some or all of the glands (lymph nodes) from under the arm, as well as the breast tumour. We need to remove at least some of the glands to see if they contain cancer. The options are:

• A sentinel node biopsy (removes an average of 2 nodes)

• An axillary sampling (removes 4-6 glands)

• An axillary clearance (removes most or all of the gland - approximately 15-25 glands)

The glands are looked at to help plan further treatment. If the glands are affected by cancer, removing them is also part of your treatment. 

What is a Sentinel Lymph Node?

In breast cancer, cells can break off from the breast lump. They travel along fine lymph channels to one lymph gland in the armpit and are held there for a time. The first node to receive cells from the breast is called the sentinel lymph node. 

An axillary sampling or axillary clearance operation does not specifically identify the sentinel node. A sentinel lymph node biopsy uses 2 special kinds of dye injected into the breast to find the most important node or nodes. Then our attention is directed to the gland most likely to contain spread from the tumour.

A recent study in the UK has shown the SLN biopsy is safe and accurate and that patients having this have fewer side effects from their surgery. The risks of arm swelling, arm discomfort and shoulder stiffness are all reduced with sentinel node surgery. The technique was developed in the USA and Europe and is used successfully around the world. 

What is involved?

A small amount of radioactive dye will be injected into the skin of your breast near the nipple 4-24 hours before your operation. Pictures will be taken of the breast and armpit using a special camera, which shows the radioactive dye. The radioactive fluid is carried along lymph vessels to the sentinel lymph node in the armpit, enabling the surgeon to find and remove this sentinel lymph node. 

The doctor will ask you to sign a consent form. This will state the operation you are having, and it is important that you understand it before signing. The side of your operation will be marked by an arrow with indelible pen. 
You will be asked by the doctor if you need to consent for any tissue/fluid samples to be used for evaluation purposes, research or quality control. 

What are the Risks?

The amount of radiation involved is less than what you would have from a mammogram. No extra precautions are needed. The safety of the procedure will be monitored by the Radiation Protection Safety Officer. A fine needle is used to inject the radioactive dye. This may cause discomfort.

What if the Sentinel Node can’t be found?

Very rarely the SLN can’t be found. Pictures taken after the radioactive dye injection may suggest the sentinel node hasn’t taken up the dye. If this happens, your surgeon will discuss the options with you before your operation and ask for your permission to perform alternative surgery on the lymph glands.

You have been diagnosed with cancer of the breast. The breast tissue drains into lymph nodes or glands under the arm. At the moment, operations for breast cancer involve removing some or all of the glands (lymph nodes) from under the arm, as well as the breast tumour. We need to remove at least some of the glands to see if they contain cancer. The options are:

• A sentinel node biopsy (removes an average of 2 nodes)

• An axillary sampling (removes 4-6 glands)

• An axillary clearance (removes most or all of the gland - approximately 15-25 glands)

The glands are looked at to help plan further treatment. If the glands are affected by cancer, removing them is also part of your treatment. 

What is a Sentinel Lymph Node?

In breast cancer, cells can break off from the breast lump. They travel along fine lymph channels to one lymph gland in the armpit and are held there for a time. The first node to receive cells from the breast is called the sentinel lymph node. 

An axillary sampling or axillary clearance operation does not specifically identify the sentinel node. A sentinel lymph node biopsy uses 2 special kinds of dye injected into the breast to find the most important node or nodes. Then our attention is directed to the gland most likely to contain spread from the tumour.

A recent study in the UK has shown the SLN biopsy is safe and accurate and that patients having this have fewer side effects from their surgery. The risks of arm swelling, arm discomfort and shoulder stiffness are all reduced with sentinel node surgery. The technique was developed in the USA and Europe and is used successfully around the world. 

What is involved?

A small amount of radioactive dye will be injected into the skin of your breast near the nipple 4-24 hours before your operation. Pictures will be taken of the breast and armpit using a special camera, which shows the radioactive dye. The radioactive fluid is carried along lymph vessels to the sentinel lymph node in the armpit, enabling the surgeon to find and remove this sentinel lymph node. 

The doctor will ask you to sign a consent form. This will state the operation you are having, and it is important that you understand it before signing. The side of your operation will be marked by an arrow with indelible pen. 
You will be asked by the doctor if you need to consent for any tissue/fluid samples to be used for evaluation purposes, research or quality control. 

What are the Risks?

The amount of radiation involved is less than what you would have from a mammogram. No extra precautions are needed. The safety of the procedure will be monitored by the Radiation Protection Safety Officer. A fine needle is used to inject the radioactive dye. This may cause discomfort.

What if the Sentinel Node can’t be found?

Very rarely the SLN can’t be found. Pictures taken after the radioactive dye injection may suggest the sentinel node hasn’t taken up the dye. If this happens, your surgeon will discuss the options with you before your operation and ask for your permission to perform alternative surgery on the lymph glands.

• Blue dye injection may be used, and this will be explained to you.

• If neither dye shows a SLN, the surgeon will perform a sampling or clearance instead.

Many thanks for taking the time to read this information sheet. If you have any further questions, please do not hesitate to speak to any member of your breast team. Breast Care Nurse Answerphone: 01752 431898.

 

Other formats

If you need this leaflet in another format such as Braille, large print, high contrast, British Sign Language or translated into another language, contact the Patient Advice and Liaison Service (PALS):

• 01752 439694

• plh-tr.PALS@nhs.net