Dynamic sentinel lymph node biopsy for penile cancer

A dynamic sentinel lymph node biopsy (DSLNB) is a test to find out if there is cancer in the lymph nodes near your cancer.

Not everyone with penile cancer needs a sentinel lymph node biopsy.

You might have this test if there is no obvious sign that cancer cells have spread to the lymph nodes after:

  • you have been examined by your specialist
  • you have had an ultrasound scan

It means that your doctor can avoid removing all the lymph nodes in the groin if this is not necessary.

You may have to travel to a specialist hospital for this test. This is because it might not be available at your closest hospital.

What is a lymph node?

A lymph node is part of the lymphatic system. This is a network of thin tubes (vessels) and nodes that carry a clear fluid called lymph around the body. This is an important part of the immune system. It plays a role in fighting infection and destroying old or abnormal cells.

The nodes are bean shaped structures that filter the lymph fluid and trap bacteria and viruses, and cancer cells.

Diagram of the lymphatic system

Why you might have this test

Sentinel nodes are the first lymph nodes a cancer might spread to. There might be more than one sentinel node. If there are no cancer cells in the sentinel node, it is unlikely that the cancer has spread to any other lymph nodes or elsewhere in the body. 

By removing and testing the sentinel node, surgeons might be able to avoid removing all of the lymph nodes (lymph node dissection). They only need to remove all the lymph nodes if the sentinel node contains cancer cells. This means testing the sentinel node can save on unnecessary surgery.

The test has two parts:

  •  a sentinel node scan to find the lymph nodes to be removed
  •  surgery to remove the lymph nodes

Preparing for your test

You should get a letter from the hospital telling you how exactly to prepare. Read this carefully and follow the instructions on there. You usually don’t need any special preparation beforehand. Let the team know if you are taking any medicines.

Your specialist will talk you through what happens and ask you to sign a consent form. This is a good time to ask any questions or talk through any worries you might have.

You have the sentinel nodes removed under general anaesthetic Open a glossary item. This means you can’t eat and drink for a few hours beforehand. Your appointment letter will tell you exactly when to stop eating and drinking.

Sentinel lymph node scan

A sentinel lymph node scan is also known as a lymphoscitogram. You have the scan in the nuclear medicine department of the hospital. You might have a numbing cream to put on your penis a couple of hours before your scan. Your doctor or nurse will tell you when and where to put it on.

Once the area is numb, a member of the nuclear medicine team injects a small amount of radioactive fluid into the area around your cancer, or where the cancer was if it has been removed. The radioactive fluid drains away into the sentinal node, or nodes, and builds up there.

You then lie in front of a special scanner called a gamma camera. This picks up the radioactive signal from the sentinel lymph nodes. Your team mark your skin over the lymph node. This is to help with surgery later.

Sometimes the lymph nodes are slower to drain. You might then come back an hour or two later to try again.

Having your sentinel node biopsy

You have surgery to remove the sentinel nodes. This might be the same day or the day after. You normally have a general anaesthetic so you are asleep and can’t feel anything.

During the operation the surgeon injects blue dye around the tumour (or where your tumour was before) where the skin has been marked. This dye allows the surgeon to see the lymph nodes.

Whilst you are asleep, your surgeon finds the sentinel node using:

  • the pictures from the sentinel lymph node scan

  • the marks on your skin

  • a smaller probe which can find the radioactive signal in the sentinel node

A small skin cut will be used to remove the sentinel nodes in each side of the groin.

This takes around 45 minutes. You wake up in the recovery area and will then go back to the ward.

After your sentinel lymph node biopsy

You usually go home the next day.

As you have had a general anaesthetic, you will need someone to take you home and stay with you for 24 hours after the operation.

The blue dye will make your urine look blue or green for the next couple of days. For some people, this can last for a few weeks. This colour change is harmless. The blue dye might be visible on your penis for a few months afterwards. 

Looking after your wound

You have a 3cm to 6cm wound in your groin where the surgeon removed the sentinel nodes. You might have a dressing over the wound. Your doctor or nurse will explain how to look after this. It can help to wear loose fitting clothes for the first few weeks.

Any stitches dissolve on their own.

Possible risks of a sentinel lymph node biopsy

A sentinel lymph node biopsy is normally a safe procedure, but your nurse will tell you who to contact if you have any problems afterwards. Your doctors will make sure the benefits of having this test outweigh these possible risks.

Possible risks include:

Allergic reaction to the blue dye

There is a small risk you will have an allergic reaction to the blue dye. Your team will monitor you carefully and give you treatment to help if this happens.


You might have some discomfort following your biopsy. Take your painkillers regularly as your team have prescribed. You might be sore for a couple of weeks.


It is normal for there to be a little bit of blood on your dressing. If it gets worse, this can be stopped by applying pressure to the area. Use a clean piece of gauze and press on the wound site for about 10 minutes. If bleeding does not stop, call the hospital.

Heavy bleeding is not normal after a sentinel lymph node biopsy. Call the hospital straight away if this happens.

Swelling and bruising

You might have some genital swelling and bruising. This is normal.

You might have fluid collecting in the groin. It can take a while for the swelling to go down.        

Contact the hospital if you:

  • have pain that is getting worse
  • have redness around the wound
  • have fluid leaking (discharge) from your wound site
  • have a high temperature
  • feel generally unwell

Fluid collecting under the skin

You may have some fluid collecting under the skin where the lymph gland has been removed. This can usually be treated.

Getting your results

It takes around 2 weeks to get the results. Your doctor will usually discuss them with you at your next clinic appointment.

Waiting for test results can be worrying. You might have contact details for a specialist cancer nurse. You can get in touch with them for information and support if you need to. It may help to talk to a close friend or relative about how you feel.

You can also call the Cancer Research UK nurses on freephone 0808 800 4040. The lines are open from 9am to 5pm, Monday to Friday.

What happens next?

A negative result means there are no cancer cells in the sentinel nodes. If there is no cancer in the sentinel nodes, the cancer is unlikely to have spread to the other lymph nodes in the groin. So, you won’t need any more lymph nodes removed.

A positive result means there are cancer cells in the sentinel nodes. If you have cancer in the sentinel nodes, the cancer has started to spread. Your doctor will talk to you about further tests and treatment. You might go on to have surgery to have all the lymph nodes removed in that groin.

  • European Association of Urology-American Society of Clinical Oncology Collaborative Guideline on Penile Cancer: 2023 Update
    O Brouwer and others
    European Urology, 2023, Volume 83, Issue 6, Pages 548-560 

  • Diagnostic Accuracy of Dynamic Sentinel Lymph Node Biopsy for Penile Cancer: A Systematic Review and Meta-analysis
    G Fallara and others
    European Urology Focus, 2023, Volume 9, Issue 3, Pages 500-512 

  • Dynamic Sentinel Lymph Node Biopsy for Penile Cancer: Accuracy is in the Technique
    Jonathan O'Brien and others
    Urology, 2022, Volume 164, Page 308

  • Cancer: Principles and Practice of Oncology (12th edition)
    VT DeVita, TS Lawrence, SA Rosenberg
    Wolters Kluwer, 2023

Last reviewed: 
20 Feb 2024
Next review due: 
20 Feb 2027

Related links