Stomach cancer
Anything that can increase your risk of cancer is called a risk factor. Those that lower the risk are called protective factors.
Having one or more risk factor doesn’t mean that you will definitely get stomach cancer.
Infection with Helicobacter pylori (H. pylori) causes around 40 out of 100 (around 40%) stomach cancers in the UK.
H. pylori is a bacteria that lives in the mucous which lines the stomach. It spreads through contaminated food and water. For most people, having an H. pylori infection will not cause any problems. But in some, H. pylori can cause inflammation and stomach ulcers. This can lead to cancer.
Other factors, such as smoking and what we eat may increase the risk of H. pylori leading to cancer.
H. pylori can be detected with a blood test, breath test or by testing a sample of your poo. The treatment is a course of antibiotics with a medicine to reduce the amount of acid in your stomach.
Find out more about H. pylori and cancer
Stomach cancer is more common in older people. Around half of stomach cancers develop in people aged 75 or over.
Men are more likely to have stomach cancer than women.
Smoking tobacco increases your risk of getting stomach cancer. Around 15 out of 100 (around 15%) of stomach cancers in the UK are linked to smoking. Your risk increases with the number of cigarettes smoked a day
It is never too late to stop smoking and you don't have to go it alone. There is help and support available to help you quit.
Find out about smoking and cancer
Stomach cancer risk is higher in people who drink 3 or more units of alcohol each day, compared with people who don't drink or only drink occasionally.
The government recommends that people drink less than 14 units a week.
Find out more about alcohol and cancer
Some occupations and working with particular chemicals can increase your risk of stomach cancer. For example working in the rubber production industry.
There is also some research linking exposure to asbestos and inorganic lead compounds to stomach cancer, however this evidence is limited.
Exposure to these kinds of chemicals at work is rare and there are regulations to protect people at work.
Stories about possible cancer causes are often in the media and it can be hard to know what’s true and what’s not. You may have heard of something that isn’t included here. This is because we only include a risk factor in this information if it is supported by good quality evidence.
Find out about common cancer myths and questions on the causes of cancer
There are ways you can reduce your risk of cancer.
Last reviewed: 28 Feb 2025
Next review due: 28 Feb 2028
Stomach cancer is when abnormal cells in the stomach start to grow and divide in an uncontrolled way. The stomach is part of the digestive system.
Symptoms of stomach cancer include difficulty swallowing, weight loss and indigestion (dyspepsia).
You should see your GP if you notice a change that isn't normal for you. They will do some tests and may refer you to a specialist if they think your symptoms could be due to stomach cancer.
The stage of a cancer tells you how big it is and how far it’s spread. It helps your doctor decide which treatment you need.
The type of stomach cancer you have depends on what type of cell it started in. The grade tells you how abnormal the cells look under a microscope. Adenocarcinoma is the most common type of stomach cancer.
There is no national screening programme for stomach cancer in the UK. But you may have tests or treatment if you are at an increased risk of developing it.
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