Sentinel Lymph Node Biopsy (SLNB): The sentinel lymph node (SLN) is the first lymph node in your armpit to which breast cancer can spread. Sometimes SLN are a group of few nodes.
Leaflet Details
| Title | Sentinel Lymph Node Biopsy (SLNB) |
| Department | Breast Clinic |
| Author(s) | Regina Santos / Manish Kothari |
| Review Date | March 2020 |
| Next Review | March 2022 |
| Download | A5 Booklet PDF |
| Accessibility Options | Click on the Recite Me button to show our accessibility resources |
Patient Information
What is a Sentinel Lymph Node?
The sentinel lymph node (SLN) is the first lymph node in your armpit to which breast cancer can spread. Sometimes SLN are a group of few nodes.
What is Sentinel Lymph Node Biopsy (SLNB)?
By removing the sentinel lymph nodes (SLN), we can find out whether the breast cancer has or has not spread to the 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.
Recent studies have shown that removal of the SLN node as opposed to traditional armpit surgery, which removes more nodes, has less side effects and has become standard treatment.
Side effects of Armpit Surgery
For some patients armpit node removal can cause temporary shoulder stiffness, severe pain, and / or permanent lymphoedema (swelling of the arm).
The side effects of armpit surgery increase with the number of nodes removed, this means if we remove only the sentinel node, side effects are less than traditional armpit surgery where more nodes are removed. Sometimes there is more than one sentinel node.
Finding the Sentinel Node
Several hours before surgery a small amount of radioactive fluid will be injected into your breast, using a very fine needle to minimise any discomfort. The dose of radiation is very small and the fluid travels to the sentinel node. There will be a stinging sensation and some discomfort when the radioactive fluid is injected into the breast. It is advisable to take simple analgesia (i.e. Paracetamol) at least an hour before your appointment.
You may have a scan to mark the position of the sentinel node some hours later. In most people this will be in the armpit but, in a small minority, it may be close to the breastbone.
All this will be carried out in the Nuclear Medicine Department and your appointment will be for either the day before or morning of your surgery.
During surgery a blue dye will be injected into the breast, after the General anaesthetic. This also travels to the SLN. Using a special detection probe the surgeon can then find the SLN.
What if we cannot find the Sentinel Node?
Occasionally the radioactive fluid or blue dye does not find the sentinel node. If this happens, the surgeon, during the same operation will remove (approximately four) nodes to make sure that the node which is likely to be the sentinel node is removed.
This does not significantly change the side effect risks.
Before your operation
You will need to sign a consent form.
- To have sentinel lymph node biopsy using radioactive fluid and blue dye.
- If the surgeon cannot find the sentinel node we need your permission to remove a sample of approximately four nodes, but this will be discussed with you when you sign your consent form
- To give permission to test your sentinel lymph node and/or any other nodes that are removed whilst you are still under general anaesthetic
- To give permission to undertake further removal of lymph nodes if the above test shows significant cancer involvement
- You may have an opportunity to participate in a research trial. If so, this will be discussed with you.
What are the advantages of Sentinel Lymph Node Biopsy over Axillary Node Clearance?
- Less discomfort and earlier mobility in the shoulder / arm.
- Less risk of lymphoedema.
- No drains under the armpit
- Shorter hospital stay and quicker overall recovery
- Targeted lymph node excision
What are the Side Effects of Sentinel Lymph Node Biopsy?
- Blue dye will discolour urine, stools, contact lenses (please remove before surgery), tears etc. for a few days.
The breast skin will be discoloured for up to a few months and very occasionally a year or so.
- Whilst under an anaesthetic allergic reaction to the blue dye seldom occurs. Should this happen it is very rarely severe and can be treated.
Contact Information
Should you have any concerns or queries then please contact the Breast Care Nurses during office hours.
Telephone numbers of Breast Care Nurses: -
- At Ashford Hospital direct 01784 884411
- St. Peter’s Hospital direct 01932 722771
- Via switchboard 01932 872000 bleep 5129
Details regarding our hospitals, including information regarding the department caring for you can be found by logging on to our website www.ashfordstpeters.nhs.uk or the National NHS website www.nhs.uk which includes an A toZ guide to health.




