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Gastrointestinal surgery research

About our research

The gastrointestinal (GI) surgery team has involvement in both upper and lower GI research. We're a research-oriented department, increasing patient participation in research. We hope that conducting research trials will help to improve treatments and ensure that NHS can provide these treatments more efficiently for patients.

Our upper GI surgical unit provides surgical services for conditions of the oesophagus, stomach, duodenum, pancreas and gallbladder. These include cancers, gastro-oesophageal reflux, gallstones, obesity and pancreatitis.

Guy's and St Thomas' NHS Foundation Trust is also a national referral centre for complex lower GI disease. The team has a strong focus on multidisciplinary education and research in all aspects of lower GI disease with close links to King’s College and London Southbank University.

The gastrointestinal (GI) surgery team conduct important research into using endoscopies to manage Barrett’s oesophagus, a condition where the cells of the oesophagus (gullet) grow abnormally and can develop into cancer in a small number of people. We also run large scale randomised controlled trials on new endoscopic techniques such as radiofrequency ablation and POEM. The Oesophageal Physiology Laboratory has an international reputation.

If attending one of our clinics, please be aware that you may be invited to take part in one of our current studies. If you would like more information on any of the studies please email us at

The Biomedical Research Centre patient and public involvement advisory group (PPIAG) develops methods of engagement with the local community. They also provide a patient/public perspective on a variety of research practices and approaches.

Current research studies

You can find out more about each study and see if you might be eligible to take part and help us with our research.

Our research team will only recruit participants currently registered with us. If you are a patient elsewhere, please consult with your gastroenterologist, who may be able to refer you to us.

If you would like more information on any of the studies, please email us at

  • RFA vs SHAM

    We are investigating a new way to treat inlet patch of the oesophagus (a change to the lining of the swallowing tube which is linked to symptoms of a feeling of a ball in back of the throat or mucus) using an endoscopic device called radiofrequency ablation (RFA -BarrX).

    The BarrX RFA device has been shown to be safe and effective for the treatment of inlet patch in a small pilot study of ten patients. It has also been shown to be safe and effective in other oesophageal conditions including Barrett’s oesophagus. The device creates a fine burn to the lining of the oesophagus and
    this is then replaced by normal (squamous) tissue. The procedure takes less than 30 minutes and is carried out as a day case.

    Participants will be randomly assigned to either treatment with RFA or to a sham procedure. A sham procedure is a dummy endoscopic treatment with RFA which looks like the real thing but is not as no treatment is provided. This is don't to rule out a placebo effect.

  • Sunflower

    Surgery to remove the gallbladder is required if it contains gallstones that cause problems. About 70,000 operations are performed annually in England. Sometimes, gallstones cause other problems if they pass from the gallbladder into the
    nearby bile duct. Then it is necessary to remove the bile duct stones before or during the gallbladder operation. Because of this, patients requiring gallbladder surgery are assessed for risk of bile duct stones. If the risk is high, further tests are done to identify if bile duct stones are present. If the risk is moderate or low, then it is uncertain whether further tests to look for bile duct stones are necessary. As a result, some surgeons choose to
    perform tests and others don’t.

    The Sunflower Study will find out whether testing for bile duct stones before gallbladder surgery is worthwhile or not in patients with a low or moderate risk of having stones. Patients who consent to participate will be divided into two groups. One group will go straight to surgery (i.e. no additional test) and the other will be tested before surgery. The ‘straight to surgery’ group will
    have twice as many people in as the ‘tested’ group to reduce the number of extra tests performed. Both groups will be followed up for 18 months and information about the need for treatment of bile duct stones, complications of surgery and costs collected.

  • Calibre

    People with long standing liver disease called cirrhosis (scarring of the liver) can develop enlargement of veins in the gullet (food pipe) known as ‘oesophageal varices’.  Patients with medium to large oesophageal varices have a one in three chance of these veins bleeding. In very severe cases, this could result in death. It is therefore important to lower the risk of this bleeding. At present, all people with medium to large oesophageal varices are offered one of two treatments to lower the risk of bleeding:

    Beta-blocker drugs

    Beta-blockers slow down the heart rate and lower blood pressure. The drugs currently prescribed are carvedilol, propranolol and nadolol. All of these drugs lower pressure in the varices which reduces the risk of bleeding.

    Carvedilol is a beta-blocker that is used to treat high blood pressure and some forms of heart disease. Research studies have shown the drug to be also very effective at lowering the pressure in varices in the gullet. It’s better than propranolol at lowering the pressure in the veins (the lower the pressure, the lower the risk of bleeding). Nadolol is similar to propranolol but is not commonly prescribed in the United Kingdom. Patients experience few side effects with carvedilol.  Patients taking beta-blockers do not require further endoscopies to check on their varices.

    Variceal banding

    A flexible tube (endoscope) with a miniature video camera and carrying a rubber ring is passed through the mouth to the gullet. An enlarged vein can be tied off with the rubber ring. Several (sometimes up to five) endoscopy sessions at approximately monthly intervals will be required to treat all of the varices.

    Subsequently, regular endoscopies are carried out at three, six then 12 months, then annually thereafter.

    Some research studies suggest that banding may be more effective than beta-blockers in lowering the risk of variceal bleeding, but other studies suggest that this is not the case.  However, all of these studies have been small and we still do not know which treatment is best.  We need to do a study to compare carvedilol with banding in people with cirrhosis who have medium to large varices that have never bled.

Previous studies

Read about past studies. Please note we are no longer recruiting participants for these trials.

  • SPIT study

    The purpose of this study is to find a quicker, less intrusive and more comfortable way than endoscopy to identify abnormalities in the oesophagus.

    Early research has suggested that human saliva contains signals of diseases that are present elsewhere in the body. It is believed that analysing a small amount of saliva for these signals, known as ‘biomarkers’, will give doctors an idea of which patients are likely to have gullet disease, so that only the minority who are at high risk will need to undergo endoscopy.

    The majority of patients who are deemed to be at low risk will no longer need to have an endoscopy. This will save people time and reduce the risks they take to find out if there is anything wrong with their gullet.

    We aim to develop a saliva screening test to accurately predict a series of gullet diseases, and reduce the number of unnecessary endoscopies performed throughout the UK. The study will aim to recruit patients who are having an endoscopy to monitor a known condition (Barrett’s oesophagus) or those with oesophageal cancer.

    1. A member of our research team will help you to complete a simple electronic questionnaire about your sociodemographic details (for example age, gender, smoking status) and your symptoms (for example heartburn).
    2. You will be asked to spit a small amount of saliva into a test tube.
    3. Following this, a simple blood test will be obtained from the intravenous line in your arm. This should not cause you further discomfort.
    4. You will then proceed to have your endoscopy examination, during which biopsies will be taken from any abnormal areas of your gullet.

    For the purposes of the study, a few additional biopsy samples of these abnormal areas, as well as normal areas, will be obtained. No more than six extra biopsy samples will be collected for the research from each patient.

    For more information please contact

  • Chronic constipation treatment pathway

    The CapCiTY research trial is funded by the National Institute for Health Research (NIHR). Here at Guy's and St Thomas' we are one of ten NHS centres conducting the largest research programme into chronic constipation, which is being coordinated by the National Centre for Bowel Research and Surgical Innovation (NCBRSI).

    The aim of the trial is to establish the most effective way to improve the symptoms of constipation and the quality of life of people suffering from chronic constipation. The research hopes to outline the suitability of these treatments to patients and also help change how treatments are used nationwide.

    The research programme is divided into three trials.

    CapCiTY trial one

    The focus of this study is to examine the treatment pathway of specialist-led retraining, to improve the symptoms of constipation. The study will compare two specialist bowel retraining programmes (habit training and direct visual biofeedback) to help identify which method of treatment is most effective.

    CapCiTY trial two

    Trial two aims to assess the effectiveness of anal irrigation as a treatment for chronic constipation, for patients whose symptoms have not been successfully treated with specialist-led bowel retraining. Anal irrigation involves putting water into the bottom to stimulate movement of the bowel. Two main systems are used to perform anal irrigation. We aim to identify which system is better for patients or if they have the same effect.

    CapaCiTY trial three

    Some patients have yet to find successful improvements in their constipation through previous treatments such as laxatives, lifestyle changes and specialist-led bowel retraining. This may be due to structural problems of the pelvic floor, for example prolapse of the bowel. An external prolapse of the rectum is when the bowel slides out of anus and an internal prolapse is when the rectum slides in on itself.

    Surgical interventions are used to improve structural problems of the pelvic floor. Laparoscopic ventral mesh rectopexy has become the standard operation for treating rectal prolapse. We aim to determine whether this method is an effective treatment for chronic constipation and assess the patient’s experience of this method of treatment.

    For more information please contact

  • Per–oral endoscopic myotomy (POEM) RCT

    We are investigating a new way to treat achalasia (a disorder of the gullet) with a minimally-invasive technique called POEM (per–oral endoscopic myotomy). This is available on the NHS in few centres around the UK.

    Although POEM is a promising treatment, we do not yet know how effective it is in the longer term compared to older but effective treatments such as balloon dilatation. The purpose of this study is to compare these two techniques.

    This is a multicentre randomised control trial. Recruitment will end once 150 patients have been randomised and treated. The lead site for this study is in Leuven, Belgium and is led by Professor Guy Boexstaens. The lead investigator at Guy's and St Thomas' is Mr Abrie Botha, consultant upper GI surgeon.

    Patients who meet the criteria will be invited to consider participation in the study. Having reviewed the study-specific patient information, discussed all treatment options and had any questions answered to their satisfaction, those who express a wish to participate will be randomised to receive either balloon dilatation or POEM.

    We will be approaching patients to take part in selected clinics: those with throat symptoms who have a confirmed diagnosis of achalasia.

    For more information please contact

  • HALO radiofrequency ablation national registry

    This national registry (UK and Ireland) for patients treated for Barrett’s oesophagus with HALO radiofrequency ablation (BarrX) is now in its tenth year.

    Originally set up at University College London (UCL), the registry has grown to 34 centres with over 1000 patients treated with the HALO device, making it the largest registry for the condition outside the USA.

    Guy's and St Thomas' contributes patients to the registry and the co-investigators are Dr Jason Dunn and Dr Sebastian Zeki.

    We will be approaching patients with Barrett’s oesophagus who are treated with HALO RFA to take part in selected clinics.

    For more information please contact

  • AspECT

    This multicentre randomised control trial, first started in 2007, is entering its final year of follow up and will close in 2018.

    The aim was to evaluate the addition of aspirin to Esomperazole as a chemo-prevention for the management of Barrett’s oesophagus. Around 1,500 patients have been recruited throughout the UK and Guy's and St Thomas' Hospital is a contributing site. Professor Jaunsz Jankowski is the chief investigator, and Dr Jason Dunn the co-investigator at Guy's and St Thomas' Hospital.


  • Dr Jason Dunn, consultant gastroenterologist, Guy's and St Thomas' Hospital
  • Dr Terry Wong, consultant gastroenterologist, Guy's and St Thomas' Hospital
  • Dr Seb Zeki, consultant gastroenterologist, Guy's and St Thomas' Hospital

Take part in a clinical trial

Find out how you can take part in a clinical trial at Guy’s and St Thomas’ and what is involved.