Stomach cancer

Your health expert: Professor Nicholas Maynard, Consultant Surgeon
Content editor review by Liz Woolf, Freelance Health Editor, March 2023
Next review due March 2026

Cancer is caused by cells in the body growing in an abnormal and uncontrolled way. Most stomach cancers are adenocarcinomas. These start in gland cells in the lining of the stomach. The information here is about this type of stomach cancer. You may hear it called gastric cancer.

Symptoms include abdominal (tummy) pain or losing weight without trying. Stomach cancer can be cured if it’s found early enough. If it’s found at an advanced stage, treatment can help control the cancer, ease your symptoms, and improve your quality of life.

About stomach cancer

In the UK, around 6,500 people get stomach cancer each year. It is one of the less common cancers and the number of people getting it has been steadily decreasing. It’s more common in other areas of the world, such as Eastern Asia, probably because of differences in diet and lifestyle.

Early symptoms of stomach cancer may be quite vague. Many stomach cancers are diagnosed when the cancer has already spread to areas nearby or to other parts of the body, such as the liver.

More than 9 out of 10 stomach cancers are adenocarcinomas.

Causes of stomach cancer

Stomach cancer is probably caused by several different factors. It’s often linked to lifestyle, including diet. Stomach cancer is more common in older people – 9 out of 10 cases are in people over 55. It’s also more common in men than women.

You're more likely to develop stomach cancer if you:

have a long-term stomach infection with a type of bacteria called Helicobacter pylori (H. pylori)
have a diet high in salt, smoked, cured, or pickled foods, or low in fruit and vegetables
smoke
drink three or more units of alcohol a day
are overweight or obese

You may also have an increased risk of stomach cancer if you are blood group A. Or if you have a condition called pernicious anaemia (your body doesn’t absorb enough vitamin B12). A small number of stomach cancers are related to the genes people have inherited.

Having any of these risk factors doesn’t mean you’ll definitely get stomach cancer – but they increase your chance of developing it. And you can still develop stomach cancer without having any of these risk factors.

Symptoms of stomach cancer

Stomach cancer symptoms can be quite vague in the early stages. For many people, indigestion is one of the first symptoms. But the symptoms which most often lead people to the doctor are:

pain in the abdomen (tummy)
losing weight without trying

Other symptoms can include:

loss of appetite
feeling unusually full after eating
difficulty swallowing
feeling or being sick
blood in your poo, which can make it look black
tiredness and breathlessness, from a lack of red blood cells (anaemia)

Many of these symptoms can be caused by other less serious conditions, such as a stomach ulcer or gallstones. However, these don’t cause weight loss, feeling full or loss of appetite. So if you have these or any other new or unusual symptoms, or if symptoms last for more than three weeks, see your GP.

You should also contact your GP if you regularly take indigestion medicines but they don’t help. Always seek medical help for difficulty swallowing.

Diagnosis of stomach cancer

Your GP will ask about your symptoms and examine you. They’ll also ask you about your medical history and will arrange for you to have blood tests.

If your GP thinks you need further investigations, they may refer you for a test called a gastrointestinal endoscopy (a gastroscopy). This involves passing a narrow, flexible, tube-like telescopic camera (an endoscope) into your mouth or nose and down into your stomach. You may have small samples of tissue (biopsies) taken from any abnormal looking areas. These are sent to a laboratory to check for cancer cells.

If you’re found to have stomach cancer, you’ll need further tests to see how far your cancer has grown and whether it’s spread. This is known as staging. You may have:

a CT scan
a PET-CT scan (a specialist CT scan using radioactive medicine to show up potential cancer cells)
an endoscopy with ultrasound, which can show how deep the cancer goes
a laparoscopy – a small operation to look inside your abdomen, using a thin tube (a laparoscope) put through small cuts in your tummy

Your doctor will explain which of these tests you may need and what they involve. Do ask your doctor if you have any questions about your tests.

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Treatment of stomach cancer

Your choice of treatment will depend on the size of your stomach cancer, where it is and whether it’s spread. Your general health and fitness will also be taken into account, along with your own wishes about your treatment.

If your cancer is still contained within the stomach, or has only spread to nearby lymph nodes, it may be possible to cure it. You are most likely to have surgery, often alongside chemotherapy. You may also have radiotherapy.

If your cancer has spread further, treatment will focus on controlling it and relieving any symptoms you have. You may have:

chemotherapy
radiotherapy
targeted or immunotherapy medicines
surgery

or a combination of these. You will also have treatment to help with any symptoms you have.

Your treatment plan will be discussed by a team, including surgeons, cancer specialists and other health professionals (a multi-disciplinary team or MDT). They will decide on the most suitable treatments for your circumstances and talk the options through with you.

Surgery

This is the main treatment for stomach cancer that hasn’t spread. It may be possible to cure your cancer. There are several different options.

For a very small cancer that is only in the stomach lining, you may have endoscopic surgery. You may hear this called endoscopic mucosal resection (EMR) or dissection (EMD). You have a flexible tube with a camera on the end (an endoscope) passed down your throat. The doctor removes the affected areas of your stomach lining and then takes out the tube. So you don’t have any cuts to your abdomen (tummy).

For larger cancers, you may have surgery to remove part or all of your stomach. These operations are called subtotal, partial, or total gastrectomies. You may be able to have keyhole surgery, also called laparoscopic surgery. This means your surgeon makes several smaller cuts in your abdomen, instead of one large one.

If your surgeon recommends surgery, they’ll explain what will happen before, during and after your operation – including potential side-effects.

Recovering from surgery

As soon as you’re able to after surgery, you can start taking sips of water. But in the first day or so after your operation, you won’t be able to eat. You may have a drip to give you fluids and sometimes a feeding tube into your bowel to help you get enough nutrition. You usually start building up to eating small amounts within a week or so.

If you’ve had all or part of your stomach taken out, you will have to change your eating habits longer term. Aim for the same amount over a day, but have it in smaller two hourly meals. Ask to see a dietician. They can give you some helpful advice.

Some foods may make you feel sick or give you diarrhoea or indigestion. Try to keep track of what foods cause you problems. You can discuss this with your nurse or dietitian, who will be able to advise you.

You may need to take supplements of some vitamins and minerals that your stomach usually absorbs. If you’ve had all of your stomach removed (a total gastrectomy), you’ll also need regular injections of vitamin B12 (usually every three months).

Some people develop a problem called dumping syndrome after stomach surgery. Food moves into your small bowel more quickly than before. This can cause unpleasant symptoms straight after eating a meal or a few hours later, including dizziness, faintness, sickness, and diarrhoea. If you have these symptoms, ask your nurse or dietitian for advice.

Chemotherapy

You may have chemotherapy before and after surgery, or only after surgery. This is to reduce the risk of the cancer coming back. Whether you have chemotherapy or not depends on how far the cancer has grown.

If your cancer has spread, your cancer specialist may suggest chemotherapy to slow down the growth of your cancer and reduce symptoms.

You have your treatment through a drip into a vein. You may also have tablets, depending on the treatment you’re having. You usually have your treatment every two or three weeks, with a rest in between.

Chemotherapy kills cancer cells, but also can damage healthy cells. The body recovers, but it’s this that causes side-effects after treatment. People are affected differently, but possible side-effects include:

increased risk of infection
tiredness (fatigue) and breathlessness
feeling or being sick
diarrhoea
hair loss or thinning

Side-effects vary depending on the chemotherapy drugs you’re having. So, ask your doctor or chemotherapy nurse for more information.

Radiotherapy

Radiotherapy uses radiation to destroy cancer cells. If you didn’t have chemotherapy before surgery, you may have it with radiotherapy afterwards (chemoradiotherapy).

Radiotherapy alone isn’t used that often to treat stomach cancer. But for a more advanced cancer, you may have it to control symptoms. This is usually a short course of treatments, called fractions.

Radiotherapy has to be carefully planned. You’ll have scans and a pre-treatment planning appointment to map out the treatment area and calculate the dose you’ll need.

Radiotherapy side-effects can include tiredness, indigestion, feeling sick, and red skin in the treatment area, similar to sunburn. They usually come on gradually and last for a few weeks after treatment. With a short course of treatment, side-effects are likely to be less. Chemoradiotherapy can have more severe side-effects.

Targeted cancer drugs

These are medicines that seek out cancer cells and interfere with the way they grow. There are many different types. Some targeted therapies are also called immunotherapy because they encourage your immune system to attack the cancer.

These treatments are currently only used for stomach cancer that has spread. Your doctor will arrange tests on cancer cells taken when you were diagnosed. This shows whether a particular targeted treatment will work for you.

Nivolumab is an immunotherapy that you may have alongside chemotherapy for stomach cancer that has spread. Or you may have trastuzumab (Herceptin®). This locks on to cancer cells and stops them growing. Again, you have it with chemotherapy.

Targeted therapies’ side-effects vary a great deal, depending on the particular drug you’re having. They often include skin rashes, diarrhoea and tiredness. Ask your doctor or nurse about side-effects for the treatment they are suggesting.

Prevention of stomach cancer

More than half of stomach cancers are preventable. You can reduce your risk of stomach cancer and benefit your overall health by making changes to your lifestyle. These include:

cutting down on salted, cured, or preserved foods, such as smoked meats and pickled vegetables
not smoking
not drinking alcohol – or having no more than one or two units a day
keeping to a healthy weight

Help and support

Being diagnosed with stomach cancer and facing treatment can be distressing for you and your family. An important part of cancer treatment is having support to deal with the emotional aspects and practical issues, as well as physical symptoms. Specialist cancer doctors and nurses are experts in providing the support you need – do talk to them about any concerns.

Weight loss is very common in people with stomach cancer. The side-effects of cancer and treatments can make it difficult to eat enough. Don’t put too much pressure on yourself when you’re having treatment. But speak to your doctor, nurse, or dietitian about how to make up for it when your treatment is over, or on days when you’re feeling better. They can make sure you’re getting any help you need, including prescribing high calorie drinks you can sip between meals.

Talking to your family and friends can help them to understand what you’re going through and how you’re feeling. Organisations and support groups that specialise in helping people with cancer can be a great source of information and support. For further details, see our section on other helpful websites below.

Symptoms of stomach cancer can be vague early on. Some people have indigestion. If you have indigestion often, stomach pain that doesn’t go away, or you are losing weight without trying, you should see your GP. See our section on symptoms of stomach cancer for more information.

If your doctor suspects you have stomach cancer, you may have some blood tests and an examination called a gastroscopy. A gastroscope is a tube with an eyepiece on one end and a camera on the other. The doctor puts the tube into your mouth or nose and down into your stomach to examine the inside of it. There is more about tests in our section on diagnosing stomach cancer.

Like many cancers, it is possible to cure stomach cancer if it’s caught early enough. This means that it hasn’t broken through the stomach wall or spread elsewhere in the body. See the section above on treatment for stomach cancer for more information.

Experts estimate that over half of all stomach cancers are preventable. Making changes to your lifestyle can lower your risk. Not smoking, not drinking too much alcohol, and eating healthily will all help. For details, see our section on preventing stomach cancer.

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Stomach cancer

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