The stomach is a muscular organ forming part of the digestive system. Food travels down the oesophagus and into the stomach to be mixed with acids and enzymes.
About 600 people are diagnosed with stomach cancer (also known as gastric cancer) each year in Victoria. Stomach cancer most commonly affects people in their late 60s to 70s, but it can, rarely, affect younger people as well. Stomach cancer affects almost twice as many men as women.
Incidence varies between countries around the world. Research suggests this can be explained to some extent by diet. Stomach cancer incidence is increased in people who eat a diet of very salty foods. The incidence of stomach cancer is very high in countries such as Japan where they eat a lot of very salty pickled foods. These foods are not commonly eaten in Australia. Infection with the bacterium Helicobacter pylori (H. pylori)
has also been shown to increase the risk of stomach cancer.Sadly, most people are diagnosed with stomach cancer when it is in its advanced stages. However, this does not mean that treatment cannot help control the cancer and relieve its symptoms.
Types of stomach cancer
The two main types of stomach cancer are:
- adenocarcinoma - more than 95 per cent of stomach cancers are adenocarcinomas. The cancer starts in the gland cells that line the stomach
- squamous cell cancer - cancer of the skin type cells that sit between the gland cells and the stomach lining.
Other very rare types of stomach cancer include a type of lymphoma of the stomach (mucosa-associated lymphoid tissue, or MALT), gastrointestinal stromal tumours (GIST) and neuroendocrine tumours of the stomach. Your doctor will be able to explain more about these types of stomach cancer.
Risks and causes for stomach cancer
The exact cause of stomach cancer is not known. However, risk factors that make a person more likely to develop this disease include:
- smoking – research shows this doubles your risk of developing stomach cancer
- age – most cases are diagnosed in people over 50 years old
- gender – it is twice as likely in men than women
- infection with the bacteria Helicobacter pylori increases the risk of stomach cancer
- if a person has had a partial gastrectomy for ulcer disease (the person may develop stomach cancer about 20 years after having this procedure)
- a genetic change (mutation in a gene) that causes a bowel disorder the most common of which are:
- familial adenomatous polyposis (FAP)
- hereditary non-polyposis colorectal cancer (HNPCC).
There is a blood test or breath test to detect helicobacter infection and it can usually be cured with antibiotics. However, it is important to mention that millions of people are infected with these bacteria. Most of them will never get stomach cancer, which means there are other factors affecting risk.
A diet high in fresh fruit and vegetables seems to lower the risk of stomach cancer, while a diet high in preserved foods or very salty food increases risk.
Family history is being researched as a risk factor for stomach cancer. You have an increased risk if you have a first-degree relative with stomach cancer. However, it is not known whether this is a genetic issue, or due to sharing other risk factors, such as Helicobacter pylori infection.
Workplace factors may also play a part. For example, workers in the metal industry appear to be at higher risk.
Researchers are looking into other risk factors such as family history, radiation exposure and regularly taking non-steroidal anti-inflammatory drugs (NSAIDs), but as yet, there are no results from further long-term clinical trials.
Symptoms of stomach cancer
The symptoms of stomach cancer are usually vague and can be common to other medical conditions. For this reason, stomach cancer is usually diagnosed in the advanced stages of disease.
Symptoms can include:
- indigestion (such as heartburn, bloating or burping)
- feeling full, even after a small meal
- nausea or vomiting (or both)
- pain and difficulty swallowing
- unexplained tiredness or weakness
- blood in vomit
- black-coloured faeces, which is a sign of old blood
- weight loss or loss of appetite – more likely in very advanced cancer.
Diagnosis of stomach cancer
Stomach cancer is usually diagnosed using a number of tests, including:
- gastroscopy – a doctor passes a thin flexible tube down your throat so they can see into your stomach, oesophagus and the upper part of your bowel
- biopsy – a doctor removes a small sample of your stomach during an endoscopy, and looks at it under a microscope
- barium x-ray (occasionally) – you swallow liquid barium, which shows up on an x-ray screen as it passes through your stomach and digestive system. This can reveal abnormalities in your stomach
- ultrasound – sound waves create a picture of your stomach
- blood tests – these include a carcinoembryonic antigen (CEA) test. CEA is produced in high quantities by some cancer cells. This occurs in about half of the people diagnosed with stomach cancer.
If you are diagnosed with stomach cancer, you may need further tests to see if the cancer has spread. These may include:
- computed tomography (CT) scan – a special x-ray taken from many different angles to build a three-dimensional picture of your body. A dye may be injected to highlight internal organs
- magnetic resonance imaging (MRI) scan – similar to a CT scan, but it uses a powerful magnet and magnetic field instead of x-rays to build three-dimensional pictures of your body
- positron emission tomography (PET) scan – a doctor gives you an injection of a glucose solution containing a very small amount of radioactive material. The scanner can ‘see’ the radioactive substance. Cancerous cells show up as ‘hot spots’ (areas where the glucose is being taken up).
Treatment of stomach cancer
Treatment depends on the type and size of the cancer, your age and health, and whether the cancer has spread. Treatments include:
- surgery – this is the main treatment in the early stages. All or part of your stomach is removed along with any cancerous lymph nodes. This is major surgery and you will need to be fit enough to have it
- chemotherapy – anti-cancer medications can stop cancer cells from multiplying. You may have this before or after surgery
- radiotherapy – radiation can kill cancer cells. Radiotherapy is not often used to treat stomach cancer, but you may receive it after surgery to destroy any remaining cancer cells or – if the cancer is very advanced – to help relieve pain
- complementary and alternative therapies – it’s common for people with cancer to seek out complementary or alternative treatments. When used alongside your conventional cancer treatment, some of these therapies can make you feel better and improve your quality of life. However, others may not be so helpful and in some cases may be harmful. It is important to tell your healthcare professional about any complementary medicines you are taking, and never stop taking your conventional treatment without consulting your doctor first. Cancer Australia has a factsheet about complementary and alternative therapies.
All treatments have side effects. These will vary depending on the type of treatment that you are receiving. Many side effects are temporary, but some may be permanent. Your doctor will explain all the possible side effects before your treatment begins.
Your sexuality and stomach cancer
Having stomach cancer and its treatment can affect the way you feel about your body, including who you are, your relationships, the way you express yourself sexually and your sexual feelings (your ‘sexuality’). These changes can be very upsetting.
Your medical team should discuss these issues with you before and during your treatment. If you feel you would like to discuss things further, ask your doctor for a referral to a counsellor or call the Cancer Council on 13 11 20 for information and support.
Caring for a person with stomach cancer
Caring for someone who has cancer can be a difficult and emotional time. If you or someone you know is caring for someone with stomach cancer, there is support available from the Cancer Council Victoria.
When a stomach cancer cure isn't possible
If a person’s stomach cancer has been diagnosed in its later stages, their cancer may have spread to the point where a cure is no longer possible. Treatment then focuses on improving the person’s quality of life by relieving the symptoms (this is called palliative treatment).
This may include surgery to relieve a blockage at the entry or exit of the person’s stomach, or medications to relieve pain, nausea and vomiting. Information and support can be found at Cancer Council Victoria.
Where to get help
This page has been produced in consultation with and approved by:
Cancer Council Victoria
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