A trial looking at the capsule sponge test to monitor Barrett’s oesophagus (BEST4 Surveillance)

Cancer type:

Oesophageal cancer





This trial is looking to see how well the capsule sponge test works to monitor a condition called Barrett’s oesophagus Open a glossary item.

Cancer Research UK supports this trial. 

There are 2 parts to BEST4:

  • BEST4 Surveillance (open to recruitment)
  • BEST4 Screening (not open yet)

This summary is about the BEST4 Surveillance part of the trial. We’ll add a summary about BEST4 Screening when it opens to recruitment.

More about this trial

Barrett’s oesophagus means that some cells in the lining of your food pipe (oesophagus) have started to change. In a small number of people these cells may develop into oesophageal cancer over a long period of time.

People with Barrett’s oesophagus usually have regular endoscopies to monitor it. The team take small tissue samples (biopsies Open a glossary item). They look for early changes in the cells. This is called dysplasia. Doctors can treat this to prevent it from developing into oesophageal cancer. 

Having an endoscopy can be uncomfortable, inconvenient and it does have some risks. And not everyone with Barrett’s oesophagus goes on to develop dysplasia. 

We know from research that a simpler, quicker capsule sponge test may be used to first check for signs of cell changes. This test uses a small sponge to collect cells from along the lining of the food pipe. Specialists can then look at the cell samples for signs of dysplasia. If the sample shows signs of cell changes, you can then have an endoscopy to confirm if dysplasia is present.

Having the sponge test means that doctors can decide when to offer an endoscopy. And it would mean some people have fewer endoscopies.

The main aim of this trial is to compare the sponge test results with the endoscopy results. This is to confirm the sponge test works well enough to pick up cell changes in people with Barrett’s oesophagus.

Who can enter

The following bullet points are a summary of the entry conditions for this trial. Talk to your doctor or the trial team if you are unsure about any of these. They will be able to advise you. 

Who can take part

You may be able to join this trial if all of the following apply. You:

  • are having regular endoscopies (surveillance) for Barrett’s oesophagus or
  • you were recently diagnosed with Barrett’s oesophagus after having the sponge test as part of the BEST4 Screening trial. This only applies when the BEST4 Screening part of the trial opens.
  • are at least 18 years old 

Who can’t take part

You cannot join this trial if any of these apply. You:

  • have severely abnormal cells (high grade dysplasia) or any diagnosis of dysplasia Open a glossary item in the inner lining of the oesophagus that was found when you had your last endoscopy 
  • have a tumour in your oesophagus, in the area of your throat at the back of your mouth (the oropharynx), or at the point where your oesophagus meets your stomach (the gastro oesophageal junction), or food gets stuck when you swallow 
  • have difficulty swallowing because you have had a stroke or you have a medical condition that affects your brain 
  • have had previous treatments to destroy abnormal cells in your oesophagus. Your doctor will know this. You may be able to take part if you had an operation to treat acid coming back up the food pipe from the stomach (acid reflux).
  • have swollen veins near to the lining of the oesophagus or liver damage (cirrhosis Open a glossary item)
  • can’t follow advice from the trial that instructs you how to take medication to thin the blood if you are to have this in preparation for the procedure. Your doctor will talk to you about this if it applies. 
  • are pregnant

Trial design

The team need 2,000 people to take part in this trial. 

Having the capsule sponge test and endoscopy 
To begin with, everyone has the capsule sponge test and an endoscopy. You may have both tests on the same day or on different days . You may have already had the sponge test if you took part in the BEST4 screening trial. If this is the case, you have only the endoscopy at this stage. The team won’t repeat the capsule sponge test. 

The capsule sponge is a small sponge inside a capsule. The capsule is suitable for vegetarians. It is similar in size to a vitamin pill and is attached to a thread. You swallow the capsule along with the string. Once swallowed, the capsule dissolves in the stomach after about 7 minutes. This releases the sponge. 

A trained nurse then gently removes the sponge by pulling the thread. This takes a few seconds. As it is pulled out, the sponge collects cells from the lining of the food pipe. The test takes around 10 minutes in total. 

You can watch a short video about having the sponge test.

Barrett's Oesophagus Screening Research | Cancer Research


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You then have your endoscopy. During this, the doctor takes samples from the lining of the food pipe. 

Capsule sponge test and endoscopy results 
The researchers compare your endoscopy and sponge test results. They use these results and other factors, such as age and sex, to decide when you should have these tests done again.

  • Everybody is invited to have both tests at 3 years.
  • Some people have another endoscopy at 3 months. This depends on their capsule sponge test results. They may then either have the capsule sponge test again at 18 months following their first procedure or they may need to leave the trial. This would be because they need treatment. 
  • Some people have another sponge test at 18 months. This depends on the result of their initial capsule sponge test result and other risk factors. 

Your doctor explains the results to you after each test. If your sponge sample doesn’t contain enough cells to give a clear result, the team might invite you to have a repeat test.

You stop taking part in the trial if your endoscopy shows you have cell changes or early cancer. You then have routine care including any treatment if you need it.

Follow up when the trial finishes
You continue to have routine endoscopies to monitor the Barrett’s oesophagus. This is only if you didn’t develop cell changes or early cancer. Your doctor will let you know how often you have these tests.

Hospital visits

You may have up to 2 extra hospital visits to have the sponge test or an endoscopy if you are offered them. All other visits are part of your routine care.

Side effects

The sponge test isn’t painful and most people find the capsule easy to swallow. You might have a mild sore throat after the sponge test. But this is also a common side effect of having an endoscopy, so you are unlikely to notice any difference.

There is a very small risk that the sponge could come off the thread in your stomach or the nurse is unable to remove it. If this happens, they remove the sponge when you have an arranged endoscopy.

There is also a very small risk of bleeding with both tests. The team will look out for this and treat it straight away. 

We have more information about having an endoscopy


Bury St Edmunds

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Dr Massimiliano di Pietro

Supported by

Cancer Research UK
Cambridge University Hospitals NHS Foundation Trust
National Institute for Health and Care Research Clinical Research Network 
NHS England
University of Cambridge

Other information

This is Cancer Research UK trial number CRUK/22/005.

If you have questions about the trial please contact our cancer information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Last reviewed:

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