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Sentinel lymph node biopsy

Find out what a sentinel lymph node biopsy is, how you have it and what happens after it.

Sentinel node biopsy is another test to find out if there are cancer cells in the lymph nodes near your cancer. You might have this test if there is no obvious sign that cancer cells have spread to the lymph nodes, to try and avoid removing lymph nodes in the groin unnecessarily. 

Why you might have this test

Sentinel nodes are lymph nodes nearest to a cancer – the first place that cancer cells will reach if they spread. 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 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. So testing the sentinel node can save on unnecessary surgery.

Having a sentinel node biopsy

Your surgeon puts local anaesthetic cream on your penis.

Once the area is numb, they inject a small amount of radioactive fluid into the area around your cancer. The radioactive fluid drains away into the lymph fluid (the fluid that circulates round body tissues) to the lymph nodes. 

You then have a scan using a gamma camera to show up the radioactive material. This shows whiether the lymph vessels around the cancer drain to the right or left groin. The doctor marks these on your skin.

You have surgery to remove the sentinel nodes. This might be the same day or the next. During the operation the surgeon injects blue dye around the tumour to show the drainage channels to the sentinel nodes. 

If there are cancer cells in the sentinel node, they will remove the rest of the lymph nodes in your groin. If they don't find cancer cells, you won’t need any more lymph nodes removed.

You will have a 3cm or 4cm wound in your groin where the surgeon removes the sentinel nodes. 

Last reviewed: 
04 Apr 2016
  • Guidelines on Penile Cancer

    O.W. Hakenberg and others

    European Association of Urology (EAU) 2014


    Diagnosis and staging of penile cancer

    C. Heyns and others

    Urology. 2010 Aug;76(2 Suppl 1):S15-23

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