Endoscopic ultrasound scan (EUS) for bile duct cancer

This test combines ultrasound and endoscopy to look at your food pipe, stomach, pancreas and bile ducts.

To do the test your doctor uses a long flexible tube called an endoscope. It has a tiny camera and light on the end and an ultrasound probe attached. The ultrasound scan uses high frequency sound waves to create a picture of the inside of your body.

The doctor can take samples of abnormal areas (biopsy) during the test.

Why you might have an endoscopic ultrasound scan (EUS)

An endoscopic ultrasound can look for a tumour or obstruction in your bile ducts. You usually have it to take samples of tissue from abnormal looking areas. It can also help doctors find out whether the cancer has spread to nearby areas.

Preparing for your EUS

You might have a blood test 2 days beforehand to check how well your blood clots.

Tell your doctor if you're having medicine that changes how your blood clots. This includes:

  • aspirin
  • clopidogrel
  • arthritis medicines
  • warfarin or heparin
  • apixaban or rivaroxaban

Your doctor tells you if you need to stop taking any other medicines.

You can't eat for 6 to 8 hours before the test but you might be able to drink sips of water up to 2 hours before your appointment. Your doctor or nurse gives you written instructions about this beforehand.

Talk to your doctor if not eating could be a problem for you. For example, if you have diabetes.

Your doctor will explain what they are going to do and you’ll sign a consent form. This is a good time to ask any questions you might have.

Before your EUS

Usually you have an endoscopy in hospital as an outpatient. A doctor or a specialist nurse (endoscopist) does the test. A nurse stays with you when you have it. The test usually takes less than 30 minutes.

When you arrive at the clinic, the staff might ask you to take your upper clothing off and put on a hospital gown. 

You might have the test while you're awake but you can choose to have a medicine to make you drowsy (a sedative).

During the EUS

You lie down on the couch and have an injection of the sedative. It takes a few minutes for you to become sleepy. The endoscopist may spray the back of your throat with local anaesthetic to numb it. 

Then the endoscopist passes the endoscope down your throat. They ask you to swallow as the tube goes down. They put a small amount of air into the tube to help them see your food pipe (oesophagus), stomach and first part of your bowel. The ultrasound gives detailed pictures of the surrounding areas such as the pancreas, bile ducts and nearby lymph nodes.

Diagram of an endoscopy

The endoscopist can take samples of any abnormal looking areas. They send these to the laboratory to be looked at closely under a microscope. 

At the end of the test the endoscopist gently removes the tube.

After your endoscopy

You need to rest for a while after the test.

You can't eat or drink for about an hour, until the local anaesthetic throat spray wears off. You might not remember much about the test if you have had a sedative drug.

You should be able to go home the same day. You can't drive or drink alcohol for 24 hours after having a sedative. You need someone to take you home from hospital and stay with you during this time.

Possible risks

An endoscopy is a very safe procedure. But your nurse tells you who to contact if you have any problems afterwards. Your doctors make sure the benefits of having an endoscopy outweigh the possible risks.

The possible risks include:

A sore throat

You might have a sore throat for up to 24 hours. Contact the hospital if you have severe pain in your throat, chest or tummy (abdomen).


You might have bloating or mild discomfort for several hours after the test. This is due to the air that the endoscopist puts into the stomach during the test.


There is a risk of bleeding from the biopsy site. This is usually a small amount and stops on its own. In rare cases you may need to have a blood transfusion.

Small tear

There is a risk of a small tear (perforation) in the food pipe, stomach or small bowel. This is rare but can be serious. 

Fluid going into your lungs

There is a very small risk of fluid going into your lungs from your mouth during the test. Your nurse uses a tube to remove most of the fluid from your mouth to reduce this risk.

Shortness of breath

A reaction to the sedative can cause breathing difficulties but this is rare. Your nurse checks your oxygen levels during the test. You have oxygen through a tube that fits into your nose (nasal cannula).

Getting your results

You should get your results within 1 or 2 weeks. 

Waiting for results can make you anxious. Ask your doctor or nurse how long it will take to get them. Contact the doctor who arranged the test if you haven’t heard anything after a couple of weeks.

You might have contact details for a specialist nurse who you can contact for information if you need to. It may help to talk to a close friend or relative about how you feel.

For information and support, you can call the Cancer Research UK nurses on freephone 0808 800 4040. The lines are open from 9am to 5pm, Monday to Friday.

Contact the doctor that arranged the test if you haven't heard anything after a couple of weeks.

Last reviewed: 
30 Sep 2021
Next review due: 
30 Sep 2024
  • The Royal Marsden Manual of Clinical Nursing Procedures (9th Edition)
    L Dougherty and S Lister
    Wiley-Blackwell, 2015

  • Guidelines for the diagnosis and treatment of cholangiocarcinoma: an update
    SA Khan and others 
    Gut, 2012. Volume 61, Pages 1657-1669

  • Biliary cancer: ESMO clinical practice guidelines for diagnosis, treatment and follow up
    JW Valle and others
    Annals of Oncology, 2016. Volume 27, Pages 28-37

  • Cancer: Principles and Practice of Oncology (10th edition)
    VT DeVita , TS Lawrence, SA Rosenberg
    Lippincott, Williams and Wilkins, 2015

  • Brush cytology, forceps biopsy, or endoscopic ultrasound-guided sampling for diagnosis of bile duct cancer: a meta-analysis
    S Bae Yoon and others 
    Digestive diseases and sciences, 2021. 

  • Diagnostic Endoscopic Ultrasound: technique, current status and future directions
    TL Ang and others 
    Gut Liver, 2018. Vol 12, Issue 5. Pages 483-496

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