How stomach cancer is diagnosed 

See your GP as soon as possible if you have stomach cancer symptoms such as indigestion, unexpected weight loss, anaemia and persistent vomiting.

Your GP will ask about your symptoms and examine your stomach for any lumpiness or tenderness. If they think that stomach cancer may be a possibility they'll refer you to a specialist for further investigation.

In 2015, the National Institute for Health and Care Excellence (NICE) published guidelines to help GPs recognise the signs and symptoms of stomach cancer and refer people for the right tests faster. Find out who should be referred for further tests for suspected stomach cancer.

Hospital tests

If your GP thinks you may have stomach cancer, they'll refer you to a specialist for tests.

These may include a blood test and chest X-ray, which will assess your overall health. A sample of your stools may also be tested for blood.

Because of the potentially serious nature of stomach cancer, you should be referred to the specialist within two weeks. Read more about waiting times.

The main tests used to diagnose stomach cancer are outlined below.

Endoscopy and endoscopic ultrasound

An endoscopy is a procedure where the inside of your body is examined using a piece of equipment called an endoscope (a long, thin flexible tube with a light and a video camera at the end).

If you need to have an endoscopy, you won't be able to eat or drink for four to eight hours before the procedure. This is to ensure your stomach and duodenum (top of the small intestine) are empty.

You'll be awake during the endoscopy, but may be given a sedative by injection to make you feel drowsy and relaxed. A local anaesthetic may also be sprayed onto the back of your throat, so the area is numbed.

The endoscope will be passed down your gullet (food pipe) and into your stomach so the specialist can look for any stomach ulcers or signs of cancer. If tissue is found that may be cancerous, a sample will be taken for testing. This procedure is known as a biopsy. The sample will be examined under a microscope in a laboratory. The results will show whether the cells are cancerous (malignant) or non-cancerous (benign) and will usually take seven to 10 days to come back.

The endoscopy itself usually takes about 15 minutes, although you should allow about two hours in total for your visit.

If your specialist thinks you may have cancer in the top part of your stomach, you may have an ultrasound scan at the same time as an endoscopy. This is known as an endoscopic ultrasound and uses high frequency sound waves to produce an image of your stomach (this method is commonly used to view an unborn baby in the womb).

If you have an endoscopic ultrasound, an ultrasound probe will be attached to the end of the endoscope before it's passed down your throat. The scan will help determine the stage of any cancer in the top part of your stomach.

After an endoscopy, or an endoscopic ultrasound, you won't be able to drive for several hours because of the sedative. You may also have a sore throat, although this should pass within a few days.

Barium meal X-ray

A barium meal X-ray or barium swallow involves drinking a chalky liquid containing a substance called barium, which makes your stomach show up on an X-ray. Nowadays, however, it's less commonly used to diagnose stomach cancers.

Organs such as your stomach don't usually show up on an X-ray because they're made of soft tissue that isn't dense enough to stop the X-rays passing through. However, when these organs are filled with barium, it blocks the X-rays and shows up white on an X-ray screen.

You won't able to eat or drink for at least six hours before the procedure because your stomach and duodenum need to be empty. You may be given an injection to relax the muscles in your digestive system.

A barium swallow usually takes about 15 minutes. Afterwards, you'll be able to eat and drink as normal, although you may need to drink more water to help flush the barium out of your system. You may feel slightly sick, and the barium may cause constipation. Your stools may be white for a few days afterwards as the barium passes through your system.

Further testing

If you're diagnosed with stomach cancer, further tests may be needed to help determine how far it's spread and how quickly it's likely to spread (known as the stage and grade). Your cancer specialist (oncologist) will discuss this with you.

However, it may not always be possible to identify the exact stage of your condition until your treatment starts.


Your specialist may need to examine your stomach in more detail to see if the cancer has spread, particularly to the lining of the abdominal cavity (peritoneum). If it has, you may need to have a small operation called a laparoscopy. This procedure is carried out under a general anaesthetic, so you'll be unconscious during it.

During the procedure, a thin viewing tube with a camera at the end (a laparoscope) will be inserted into your stomach through a small incision in the lower part of your tummy. In some cases, your specialist may need to examine more than one area of your stomach and make more than one incision.

Computerised tomography or positron emission tomography scans

During CT scans or PET scans, a series of X-ray images of your body are taken. A computer is then used to put the images together and create a detailed picture of the inside of your body.

These scans will help your doctor assess how advanced your cancer is. It allows them to see whether the cancerous cells have formed tumours anywhere else in the body. The scans can also help your doctors work out which type of treatment will be most effective and appropriate for you.

Liver ultrasound scan

If your specialist thinks your stomach cancer may have spread to your liver, you may need to have a liver ultrasound. This type of scan uses high frequency sound waves to produce an image of your liver.

Staging and grading

After all of the tests have been completed and your test results are known, it should be possible to tell what stage and grade of stomach cancer you have.

Staging is a measurement of how far cancer has spread. There are a number of different ways stomach cancer can be staged. One method uses a numbering system from one to four. The higher the number, the further the cancer has spread.

The majority of stomach cancers are at stage three or four when diagnosed, which means a cure isn't usually possible.

Grading describes how quickly the cancer is likely to spread in the future. There are three grades of stomach cancer:

  • low-grade – the cancer tends to grow slowly
  • medium-grade – the cancer grows a bit faster
  • high-grade – the cancer is aggressive and likely to grow quickly

Cancer Research UK has more information about the staging and grading of stomach cancer.

Page last reviewed: 28/10/2015

Next review due: 28/10/2017