Does H.pylori cause cancer?

What is H. pylori?

H. pylori is a type of bacteria that infects the lining of the stomach. It is spread through contaminated food and water and normally infects people during childhood.

The infection is no longer common in the UK.

But if you're worried that you might have an H. pylori infection, speak to your doctor. An infection can be detected with a blood test, breath test or by testing a sample of your poo.

H. pylori infections can be treated with antibiotics and normally, the infection won’t cause a person any problems at all. Some people won’t even know they’ve had it, as it doesn’t usually cause any symptoms. If you have been prescribed antibiotics, it's important to use them as directed by your doctor.

In some cases H. pylori can cause cancer, but this is rare.

How can H. pylori cause cancer?

For most people the infection won't cause them any problems. But in some, H. pylori can cause long-lasting irritation, swelling and pain in the stomach (known as ‘severe chronic atrophic gastritis’ or SCAG) and stomach ulcers. This can lead to cancer.

Millions of people around the world are infected with these bacteria and only very few (between 1 and 3 out of 100) go on to develop stomach cancer. Researchers think this is because some types of H. pylori are more likely to cause problems than others.

And other things, such as smoking and what we eat, can also increase the risk that H. pylori infection will lead to cancer.

What cancers are linked to H. pylori?

H. pylori increases the risk of stomach cancer, especially a type called non-cardia gastric cancer.

Some stomach cancer cases in the UK are caused by these bacteria. But, as H. pylori infection has become much less common in the UK, stomach cancer rates have dropped.  

In the UK, there are other ways to reduce stomach cancer risk that are likely to have a bigger impact than treating H. pylori. This includes stopping smoking, and eating a healthy, balanced diet, high in foods with lots of fibre, like wholegrains, and low in red and processed meat.

Read more about how 4 in 10 cancer cases could be prevented.

H.pylori increases the risk of non-Hodgkin lymphoma

About 3 in 100 cases in the UK are caused by H. pylori.

H.pylori may reduce risk of oesophageal (food pipe) cancer

There is some evidence that H. pylori could been linked to a reduced risk of oesophageal cancer, but it is unclear why this is the case. It may be because people with H. pylori infection have less damage to the cells in their food pipe from acid reflux.