Sentinel lymph node biopsy (SLNB) for vulval cancer

What is a sentinel lymph node biopsy (SLNB) for vulval cancer?

This test checks lymph nodes near the vulva for signs of cancer. It can find small amounts of cancer that cannot be felt as swelling or seen on a scan.

Lymph nodes are part of the immune system and they help protect us from infection and disease. Sometimes, vulval cancer can spread through the lymph nodes. The sentinel nodes are the first lymph nodes that fluid drains to from the vulva. If the vulval cancer has spread to nearby nodes, these sentinel nodes are most likely to be affected.

A sentinel lymph node biopsy (SLNB) is a small operation to find the sentinel lymph nodes and remove them. It is done under a general or regional (spinal) anaesthetic. It is usually at the same time as an operation to remove the cancer.

Before a sentinel lymph node biopsy for vulval cancer

Before the SLNB, you usually have a scan to show the sentinel lymph nodes. Your scan may be the day before or the same day as the SLNB.

For the scan, you undress from the waist down. You then lie down on your back. The doctor uses local anaesthetic cream or a spray to numb the area of the vulva affected by cancer. They gently inject a small amount of radioactive liquid. The liquid drains into the nearest lymph nodes. You have scans over the next 90 minutes to show how and where the liquid goes. The doctor may also make marks with a marker pen on your skin. These marks and the scan pictures are useful when you have the SLNB.

During a sentinel lymph node biopsy for vulval cancer

During the operation, the doctor injects a dye into the area of the vulva affected by cancer. The dye stains the lymph nodes so the surgeon can find them. The surgeon also uses a probe that detects the radioactive liquid from the scan. They carefully find the sentinel lymph nodes and remove them.

After a sentinel lymph node biopsy for vulval cancer

After surgery, the nodes are sent to a laboratory and examined under a microscope to see if they hold cancer cells. If they show cancer cells, the remaining groin lymph nodes will need to be removed with another operation or treated with radiotherapy. If the sentinel nodes do not contain cancer cells, it is unlikely that other lymph nodes are affected. You do not need to have further surgery or radiotherapy.

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 Senior Medical Editor, Professor Nick Reed, Consultant Clinical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We try to make sure our information is as clear as possible. We use plain English, avoid jargon, explain any medical words, use illustrations to explain text, and make sure important points are highlighted clearly.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected. Our aims are for our information to be as clear and relevant as possible for everyone.

You can read more about how we produce our information here.