A trial looking at the Cytosponge test in GP surgeries for people with heartburn symptoms (BEST3)

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Oesophageal cancer





A small number of people who have long term symptoms of heartburn or acid reflux might develop a condition called Barrett’s oesophagus. 

Having Barrett’s oesophagus slightly increases your risk of cancer of the food pipe (oesophageal cancer). This is a small increased risk. Many people with Barrett’s oesophagus do not develop cancer of the food pipe

Cancer Research UK supports this study.

More about this trial

People with Barrett's opesophagus are closely monitored. This way if cancer is found, they are diagnosed early and can start treatment as soon as possible.

Barrett’s oesophagus can be diagnosed by collecting a sample of tissue (biopsy Open a glossary item) from the lining of the food pipe. This is done during an endoscopy. But endoscopy can be uncomfortable and does have some risks.

We know from research that the Cytosponge is safe and can be used to diagnose Barrett’s oesophagus. 

For the Cytosponge test you swallow a small capsule with a sponge inside. The sponge is attached to string which you or the nurse uses to pull the sponge out. This takes a sample of the cells of the lining of the food pipe which then can be tested. 

In this trial the researchers are looking at whether the Cytosponge test can be used in GP surgeries.

The main aim of this trial is to see whether by offering the Cytosponge test, more people with Barrett's can be diagnosed, compared to the number of people diagnosed in the standard practice. 

Who can enter

The following bullet points list 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. 

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

  • Have received a letter of invitation from your GP (you are invited to take part in this trial, you cannot volunteer)
  • Have had medication prescribed by your doctor that reduces the amount of acid in your stomach (acid suppressant medication) for at least the past 6 months
  • Are at least 50 years old

You cannot join this trial if any of these apply. 

  • You are getting regular prescriptions of medication called a non steroidal anti inflammatory drug (NSAID Open a glossary item)
  • You are getting regular prescriptions of a drug called Clopidogrel
  • You have had an endoscopy of the food pipe (oesophagus) in the past 5 years
  • You have been diagnosed with cancer of the back of the mouth (oropharynx), cancer of the food pipe (oesophagus) or cancer where the food pipe joins the stomach (gastro oesophageal junction)
  • You have been diagnosed with Barrett’s oesophagus
  • You aren’t able to get to the GP surgery
  • Your GP doesn’t think you should take part

Trial design

Researchers want 120 GPs to take part in the trial. Half of people (50%) will be offered the Cytosponge with usual care. The other half will continue to receive their usual care only. 

Researchers will look at the databases of the 120 GPs to find people who might be able to take part in the trial. A letter of invitation is posted to these people. They can choose:

  • to allow the researchers to collect information from your medical notes –  you won’t be able to be identified (anonymous) and the information will be confidential
  • to have the Cytosponge test in addition, if your GP is doing it
  • not to take part at all

The team need 12,500 people to join the trial.

  • 6,250 people from GPs who are doing the Cytosponge with usual care
  • 6,250 people from GPs who are doing usual care only

Cytosponge is a capsule about the size of a vitamin tablet. It contains a small sponge attached to string. The other end of the string is attached to a card that you or the nurse holds. You swallow the capsule with a glass of water.

BEST3 diagram

After about 5 minutes the capsule dissolves in your stomach. The sponge inside is released. The nurse then gently pulls the string to remove the sponge. On the way out the sponge collects cells from the lining of your food pipe. 

Barrett's Oesophagus Screening Research | Cancer Research

View a transcript of the video about the cytosponge.

The sponge might cause a bit of discomfort as it is pulled out. The nurse will remove the sponge quickly but delicately to avoid discomfort. You can also have your throat sprayed with an anaesthetic drug before pulling the sponge out. This will numb your throat.

The sponge is sent to the laboratory to look for chemical substances (markers Open a glossary item) in the cells. This might show you have Barrett’s oesophagus. Or your test result might not show any Barrett’s oesophagus (a negative result).

After 4 to 6 weeks your GP will have the results. They will discuss this with you and then decide if your treatment needs changing or if you should have an endoscopy.

You have an endoscopy if the Cytosponge test shows that markers are present. The endoscopy is to confirm if you have Barrett’s oesophagus or not. Your appointment for the endoscopy will be within 6 weeks of getting the results of the Cytosponge.

An endoscopy is an examination of your food pipe. A thin tube with a camera on the end goes down your throat so the doctor can have a look at the lining of your food pipe. They will take small samples of tissue (biopsies) for some tests.

A year after joining the study the team might invite you to have an endoscopy if you haven’t had one. This also includes people who had usual care only. They will use the results of the endoscopies to find out how often a diagnosis of Barrett’s oesophagus might be missed.

When you agree to join the study you fill in a questionnaire about your general health, lifestyle and heartburn or reflux symptoms.

About 2 weeks later the team will post you another questionnaire. The questions ask about your experience of having the Cytosponge test done. A stamped addressed envelope is provided for you to post the questionnaire back.

Hospital visits

Before you have the Cytosponge test the nurse:

  • will ask for a spit (saliva) sample
  • will take your height, weight and hip measurement

A week to 2 weeks afterwards a member of the team will phone you to see how you are.

A small number of people may receive a positive test result. If this happens, they will have an endoscopy at their local hospital to check for any problems.

Side effects

Over 3,000 people have had the Cytosponge test done and there have been no serious side effects reported.  

You might have a mild sore throat for about a day afterwards. 

There is a very small risk you might have some bleeding. Your GP or clinic nurse will assess you if this happens. You also have a card of instructions to follow if this happens at home. 

There is a very small risk that the sponge might become detached from the string. Or that it will be difficult to remove the sponge. Your GP will assess you and arrange an endoscopy at the local hospital where the sponge can be safely removed.

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

Professor Rebecca Fitzgerald

Supported by

Cambridge University Hospitals NHS Foundation Trust
Cancer Research UK
MRC Cancer Unit - University of Cambridge
Queen Mary University of London

Questions about cancer? Contact our 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.

Charlie took part in a trial to try new treatments

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“I think it’s really important that people keep signing up to these type of trials to push research forward.”

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