A trial looking at a new treatment for 2 pre cancerous conditions affecting the food pipe (HALO)

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

Cancer type:

Oesophageal cancer





This trial is looking at a treatment that uses heat from radio waves to destroy abnormal cells (radiofrequency ablation) lining the food pipe (oesophagus). It is open to people with Barrett’s oesophagus or abnormal changes to squamous cells in the food pipe (squamous dysplasia).

If you have Barrett’s oesophagus or squamous dysplasia, it is possible that these conditions could become either adenocarcinoma or squamous cell cancer of the food pipe. Doctors want to be able to treat these conditions before they turn into cancer.

More about this trial

There is a way of treating these cell changes called HALO radiofrequency ablation. The HALO tool attaches to a thin flexible tube with a light on the end (an endoscope). The doctor passes the endoscope into the food pipe. They then look down the endoscope and use HALO to kill off any abnormal cells they can see. The body then replaces dead abnormal cells with healthy cells.

Trials in the USA and Europe have suggested that this treatment is safe and works well for these conditions. NICE recommends this treatment for Barett's oesophagus. As well as treating people with Barrett’s oesophagus and squamous dysplasia, the aim of this trial is to build a long term record of treatment effects (a ‘registry’).

Who can enter

You can enter this trial if you

  • Have a condition called Barrett’s oesophagus that needs treatment or squamous dysplasia of the food pipe
  • Are able to have an endoscopy
  • Are willing to use a reliable form of contraception if it is possible for you to become pregnant
  • Are at least 21 years old

You cannot enter this trial if you

  • Have cancer of the food pipe (oesophagus)
  • Have enlarged veins close to the lining of your food pipe which may bleed severely (‘oesophageal varices’)
  • Have had radiotherapy for cancer of the food pipe
  • Have had surgery to cut the ring of muscle at the lower end of your food pipe, to allow food and drink to pass into your stomach more easily (‘Heller’s myotomy’)
  • Are pregnant

Trial design

This trial will recruit more than 1,700 people.

Everyone taking part will have one or more HALO treatments, depending on their situation.

You have HALO as a day patient. If you take any medication to stop your stomach making acid, you should take this before the procedure. You then lie on your left side. You will have an injection through a drip into a vein in your arm or hand to make you feel sleepy (a sedative). The doctor will then pass a thin flexible tube with a camera and light on the end (an endoscope) through your mouth and into your food pipe to the area that needs treating. You then have HALO treatment every 2 to 3 cm along this area. The whole procedure will take between 30 to 45 minutes. You should not remember anything about this treatment as you will be sleepy all the way through.

You then have regular check ups and more HALO treatment if you need this.

If you need to have tissue samples (biopsies) taken, the team will ask your permission to collect some extra samples for the trial. They will take up to 4 extra samples of tissue, and 2 samples of cells collected with a small brush (‘brushings’). They will use these samples to understand why this treatment does not always work for everyone. Also, by linking gene features (‘markers’) from these samples to people’s treatment outcomes, they hope to be able to work out who HALO will help in future.

Hospital visits

Before you start the trial you will see the doctor, and have a pregnancy test if appropriate. You may also have some more tests to confirm your diagnosis. These may include

You come to hospital for the day for your HALO treatment. You then have regular check ups and possible further HALO treatments, depending on your condition.

If you have Barrett’s oesophagus, you have

  • An endoscopy with HALO every 2 to 3 months for up to a year, until doctors cannot see any more abnormal areas, then
  • A biopsy to check for any very tiny abnormal cells, then
  • Endoscopy with biopsy every 2 to 3 years

If you have squamous dysplasia, you have an endoscopy with biopsy about 3 months after your HALO treatment. If everything is normal, you then repeat this

  • 6 months after HALO
  • 12 months after HALO
  • Every 1-2 years after this

If any of these tests show that you have more Barrett’s cells or squamous dysplasia, you will have more HALO treatment.

It is usual to continue to have check ups for these conditions. You will stay in the trial for as long as you need these, so you can have the treatment, and the team can collect long term information about it.

Side effects

Side effects of HALO treatment include

  • Narrowing of your food pipe (oesophageal stricture) – this is rare and can be treated
  • Temporary chest discomfort

The risks of any side effect from HALO would be the same as if you were having this treatment outside of the study. Your study doctor will also talk to you about possible risks of endoscopy, ablation and biopsy.

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

Prof Laurence Lovat

Supported by

Experimental Cancer Medicine Centre (ECMC)
University College London Hospitals NHS Foundation Trust

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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