This page has been designed to provide information regarding a clinical procedure called endoscopic submucosal dissection (ESD) which you have been offered. It aims to explain why the procedure is being offered, what you have to do to prepare and to answer some of the questions you may have. Please ask if there is anything you do not understand it or if you have any questions.
ESD is a procedure where a lesion or polyp is removed from either your oesophagus (gullet) or from your stomach. The procedure is carried out using a flexible tube called a gastroscope. This is passed through the mouth to access and assess the area of irregularity that requires treatment.
The procedure is usually performed under a General Anaesthetic. When the lesion has been located, it is raised by injecting fluid into the tissue underneath. This makes it easier and safer to remove the lesion The lesion is then removed using diathermy (heat treatment) which allows the lesion along with some of the tissue underneath to be cut and removed. You will not feel this.
Your previous endoscopy or test has found a lesion or polyp in your oesophagus (gullet) or stomach. Removing the lesion in one piece gives the pathologists (doctors) who examine the tissue under the microscope the best opportunity to know if the lesion has been completely removed. The samples taken will be sent directly to the laboratory and so the results will not be available straight away You will be given a follow up appointment with your doctor to discuss the results once they are available.
For most people an endoscopy is a simple and safe procedure. All treatments and procedures do, however have risks, and we will talk to you about the risks of endoscopy and those specific to ESD at an outpatient appointment before the procedure.
Problems that may happen straight away
As with all endoscopic treatment the most common risks are damage to or perforation (a hole) in the oesophagus or stomach, bleeding requiring intervention, infection and damage to teeth.
If bleeding occurs which requires treatment it can usually be treated during the procedure.
Small perforations can sometimes also be treated during the procedure but larger perforations may require surgery with admission to hospital.
Problems that may happen later
You may experience a sore throat and discomfort for one to two days after the procedure.
Delayed bleeding occurring after you have been discharged may require you to be admitted to hospital for treatment. It is also possible that you may be left with an undiagnosed perforation. These complications are uncommon and will be discussed with you by the endoscopist performing the procedure. If you have any problems after the procedure such as bleeding, or abdominal pain please contact us as soon as possible on the telephone numbers at the end of this page.
There is a risk that as your oesophagus /gullet heals it will narrow which is likely to make swallowing difficult. We will discuss the risks of this in more detail when we speak to you in clinic, but this is usually treatable with a repeated endoscopy and dilatations.
You may be offered other treatment options including surgery. This will be discussed with you in more detail during your follow up Consultation.
Please do not eat or drink for six hours before the examination. You may have sips of water up to two hours before the test.
On the day of your test, please bring a list of all the medications you are currently taking. You will be admitted for at least one night after your procedure. Please pack a bag of essentials accordingly.
If you are taking any blood thinning medications such as warfarin, clopidogrel, rivoroxaban, apixaban or any others, you should receive specific instructions on what to do regarding these medications during your clinic appointment.
If you have not received this information, or if you have any questions, please contact Endoscopy Recovery on 020 3447 3282.
If you are diabetic and take insulin, it is important that you continue taking your insulin. We will advise you how much to reduce your insulin when you are seen in clinic before your procedure. If you take diabetic tablets, please do not take them on the day of the procedure until after it has been done.
If you are pregnant, or think you may be pregnant, you should not undergo this procedure. If you are of childbearing age, you will need to take a urine test to see if you are pregnant before you can have this procedure.
When you arrive at the Endoscopy Unit please report to the reception. From there a nurse will take you to admissions, check your personal details, check your blood pressure and you will be asked to change into a hospital gown if needed. When it is time for your procedure, you will be taken to the consenting room where you will meet the endoscopist and be asked to sign a consent form.
We want to involve you in all the decisions about your care and treatment. If you decide to go ahead with treatment, by law we must ask for your consent and will ask you to sign a consent form. This confirms that you agree to have the procedure and understand what it involves. Staff will again explain all the risks, benefits and alternatives before they ask you to sign a consent form. If you are unsure about any aspect of your proposed treatment, please ask.
From there, we will take you into one of the endoscopy rooms. You will be able to take your belongings with you or they may be left with friends or relatives. Friends and relatives can wait in the waiting room.
The anaesthetist will administer the sedation or anaesthetic via a small needle in the back of your hand. Drugs usually take a few minutes to make you relaxed and make you go to sleep. Your vital signs will be constantly monitored during the procedure and you may also be given a small amount of oxygen during the procedure.
Once you are comfortable, the endoscopist will start the procedure by passing a thin, flexible tube called an endoscope into your mouth. Once the doctor has identified the area to be removed, an ESD will be performed.
After you have had your procedure, you will be taken to the recovery area. You will be kept there for approximately one hour so the effects of the sedation can wear off. Your blood pressure and oxygen levels will be monitored during this time.
When you are fully awake, one of the doctors will come to explain the results of your procedure. You will then be transferred to a ward for an overnight stay.
When you are well enough to be discharged, will receive an information sheet giving advice on aftercare and details of who to contact if you have any problems. A plan will also be made to see you again in clinic to discuss the results of the procedure.
Do read section seven regarding medicines.
Do ask for an interpreter if you require one, as hospital policy states that family or friends cannot interpret on behalf of the patient.
Do not drink milk six hours before the procedure.
Do not bring large sums of money or valuables to the hospital as we cannot accept responsibility for loss or damage.
Pathway Co-ordinator (Monday to Friday 09:00-17:00)
Direct line: 0203 447 7488
Switchboard: 08451 555 000 / 020 3456 7890 ext. 71488
E-mail: uclh.
Endoscopy Recovery (Monday to Friday 09:00-17:00)
Direct line: 020 3447 3282
Switchboard: 08451 555 000 / 020 3456 7890 ext. 73282
Address: Endoscopy Unit, University College Hospital, 2nd Floor Podium, 235 Euston Road, London, NW1 2BU
Services
Page last updated: 03 March 2026
Review due: 01 June 2027