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How are stomach and oesophageal cancers diagnosed?

If your GP suspects that you have stomach or oesophageal cancer, they will examine you and refer you to a specialist for further tests. The main tests are endoscopy and biopsy (the removal of a tissue sample). You may have other tests to check your overall health and see if the cancer has spread. Your specialist will combine the test results to work out the overall stage and prognosis of the cancer.

An endoscopy (also called a gastroscopy, oesophagoscopy or upper endoscopy) is a procedure that allows your doctor to look at the lining of your gastrointestinal tract. It is usually done as day surgery.

Having an endoscopy – You will be told not to eat or drink (fast) for six hours before an endoscopy. In some cases, you can drink clear fluids until two hours before the procedure. Your doctor will let you know about this. Before an endoscopy, some specialists may spray the throat with a local anaesthetic to numb it, but more commonly you will be given a sedative into a vein to make the procedure more comfortable. A long, flexible tube with a light and small camera on the end (endoscope) will then be passed into your mouth, down your throat and oesophagus, and into your stomach and small bowel.

Taking a biopsy – If the doctor sees any areas that look like cancer, they may remove a small amount of tissue from the stomach or oesophageal  lining. This is known as a biopsy. A specialist doctor called a pathologist will examine the tissue under a microscope to check for signs of cancer. Biopsy results are usually available in 5–7 days.

An endoscopy takes about 10 minutes. You will need to have someone take you home after the procedure, as you may feel drowsy or weak. You may have a sore throat afterwards and feel a little bloated. Endoscopies have some risks, such as bleeding or getting a small tear or hole in the stomach or oesophagus (perforation). These risks are very uncommon. Your doctor should explain all the risks before asking you to agree (consent) to the procedure.

Endoscopic ultrasound (EUS)

You may have an EUS at the same time as a standard endoscopy. The doctor will use an endoscope with an ultrasound probe on the tip or with a built-in ultrasound device. The probe releases soundwaves that echo when they bounce off anything solid, such as an organ or tumour. This test helps work out whether the cancer has spread into the oesophageal or gastric wall, nearby tissues or lymph nodes. During the EUS, your doctor may use the ultrasound to guide a needle into the area they want to look at and take tissue samples.

If the biopsy shows you have stomach or oesophageal cancer, you will have some of the following tests to work out whether the cancer has spread to other areas of your body. This is called staging. Some of the tests may be repeated during or after treatment to check your health and see how well the treatment is working.

Blood tests

You may have blood tests to assess your general health, check for a low red blood cell count (anaemia), and see how well your liver and kidneys are working. Blood tests can also help show if you are getting enough vitamins or minerals.

CT scan

A computerised tomography (CT) scan uses x-ray beams to create detailed, cross-sectional pictures of the inside of your body. It helps show the size of the cancer and if it has spread. You may have a CT scan of your:

  • chest, abdomen and pelvis for stomach cancer
  • neck, chest, abdomen and pelvis for oesophageal cancer.

Before a CT scan, you may have an injection of dye and/or be asked to drink a liquid dye. If you have an injection, a cannula is inserted into a vein on your arm. This dye, known as contrast, helps ensure that anything unusual can be seen more clearly. The dye may cause a warm feeling throughout your body, and leave a metallic taste in your mouth for a few minutes. Rarely, more serious reactions may occur.

The CT scan machine is large and round like a doughnut. You will need to lie still on a table while the scanner moves around you. The scan itself is painless and takes only a few minutes, but it usually takes 10–30 minutes for the sonographer to prepare the CT machine and insert the cannula.

PET–CT scan

A positron emission tomography (PET) scan combined with a CT scan is a specialised imaging test. The CT scan helps pinpoint the location of any abnormalities found by the PET scan. For oesophageal cancer, a PET–CT scan is most commonly used to see if the cancer has spread to other parts of the body. As a PET–CT scan is not useful in finding some types of stomach cancers, Medicare does not currently cover the cost of this test.

To prepare for a PET–CT scan, you will be asked not to eat or drink (fast) for a period of time. Before the scan, you will be injected with a glucose solution containing a small amount of radioactive material. Cancer cells show up brighter on the scan because they take up more glucose solution than normal cells do.

You will be asked to sit quietly for 30–90 minutes as the glucose spreads through your body, then you will be scanned. The scan itself takes about 30 minutes. Let your doctor know if you are claustrophobic, as you need to be in a confined space for the scan.

Before having scans, tell the doctor if you have any allergies or have had a reaction to contrast during previous scans. You should also let them know if you have diabetes or kidney disease or are pregnant or breastfeeding.


This procedure allows your doctor to look for signs that the cancer has spread to the outer layer of the stomach and the lining of the wall of the abdomen, which are known as the peritoneum. A laparoscopy is used to stage stomach and oesophageal cancers. Your doctor will explain the risks before asking you to agree to the procedure.

A laparoscopy is usually done as day surgery under general anaesthetic. The doctor will make small cuts in your abdomen and pump in gas to inflate it. A tube with a light and camera attached (a laparoscope) will then be inserted into your body. The camera projects images onto a monitor so the doctor can see cancers that are too small to be seen on CT or PET–CT scans. The doctor may take more tissue samples for biopsy. After the procedure you may feel bloated and the gas in your abdomen may cause pain in your shoulder.

Staging endoscopic resection

If you are diagnosed with very early cancer in the stomach or oesophagus, you may have an endoscopic resection.

This procedure may help your doctor work out whether the cancer has spread to the lymph nodes. For some people, the resection also treats the cancer and further treatment is not needed. An endoscopic resection is often done as a day procedure but in some cases, you may stay in hospital overnight for observation.

Molecular testing

If you are diagnosed with advanced cancer in the stomach or gastro-oesophageal junction, your doctor may test the biopsy sample to see whether one of the available targeted therapy or immunotherapy drugs would be suitable for you.

The test will look for particular features within the cancer, such as changes to the HER2 protein, a special protein known as PD-L1, or a marker called microsatellite instability (MSI). This type of testing is known as molecular testing.

Featured resources

Oesophagogastric cancer - Your guide to best cancer care

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Understanding Stomach and Oesophageal Cancers

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This information is reviewed by

This information was last reviewed October 2021 by the following expert content reviewers: Dr Spiro Raftopoulos, Gastroenterologist, Sir Charles Gairdner Hospital, WA; Peter Blyth, Consumer; Jeff Bull, Upper Gastrointestinal Cancer Nurse Consultant, Cancer Services, Southern Adelaide Local Health Network, SA; Mick Daws, Consumer; Dr Steven Leibman, Upper Gastrointestinal Surgeon, Royal North Shore Hospital, NSW; Prof Michael Michael, Medical Oncologist, Lower and Upper Gastrointestinal Oncology Service, and Co-Chair Neuroendocrine Unit, Peter MacCallum Cancer Centre, VIC; Dr Andrew Oar, Radiation Oncologist, Icon Cancer Centre, Royal Brisbane Hospital, QLD; Rose Rocca, Senior Clinical Dietitian: Upper Gastrointestinal, Nutrition and Speech Pathology Department, Peter MacCallum Cancer Centre, VIC; Letchemi Valautha, Consumer; Lesley Woods, 13 11 20 Consultant, Cancer Council WA.