Does H.pylori cause cancer?
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- Yes, infection with Helicobacter pylori (H. pylori) increases the risk of some cancers
- But, it can decrease the risk of oesophageal cancer
- For most people, H. pylori will not cause any problems and it can be treated
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 very common in developed countries like the UK.
It can be treated with antibiotics and normally, the infection won’t cause a person any problems at all. But, rarely it can cause cancer.
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 inflammation in the stomach (known as ‘severe chronic atrophic gastritis’ or SCAG) and stomach ulcers. This can lead to development of 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 that are linked to causing cancer, such as smoking and what we eat can also affect our risk.
What cancers are linked to H. pylori?
- Stomach cancer, especially a type called non-cardia gastric cancer.
More than 4 in 10 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. This may be partly due to changing levels of H. pylori.
There are other ways to reduce cancer risk that are likely to have a bigger impact than treating H. pylori. This includes giving up smoking and eating a healthy, balanced diet. You can find out more on our website here.
- Non-Hodgkin Lymphoma (a type of blood cancer)
About 3 in 100 cases in the UK are caused by H. pylori.
There is some evidence that bowel cancer risk may also be increased in people with H. pylori. But this is less well understood, and more research is needed.
- Oesophageal (food pipe) cancer
H. pylori has been linked to a reduced risk, but it is unclear why this is the case. It may be because of reduced damage to cells in the food pipe from acid reflux in those that have H. pylori.
H. pylori infection can be detected with a blood test or a breath test. If you're worried that you might have an H. pylori infection, speak to your doctor. It can usually be cured with a course of antibiotic treatment.
Treating H. pylori infection can reduce the risk of stomach cancer. But having the infection could lower the risk of oesophageal cancer. So, treating H. pylori infection might not be beneficial unless you have symptoms, such as stomach pain.
In the UK, other ways to reduce stomach cancer risk are likely to have a bigger impact than worrying about H. pylori. This includes eating a healthy, balanced diet, high in foods with lots of fibre, like wholegrains, and low in red and processed meat, and stopping smoking.
International Agency for Research on Cancer. IARC Monograph 100B: Biological Agents. (2012)
Brown KF, Rumgay H, Dunlop C, et al. The fraction of cancer attributable to modifiable risk factors in England, Wales, Scotland, Northern Ireland, and the United Kingdom in 2015. Br J Cancer. (2018)
Lee Y-C, Chiang T-H, Chou C-K, et al. Association Between Helicobacter pylori Eradication and Gastric Cancer Incidence: a Systematic Review and Meta-analysis. Gastroenterology. (2016)
Eross, B et al. Helicobacter pylori infection reduces the risk of Barrett's esophagus: A meta-analysis and systematic review. 23(4) (2018) https://www.ncbi.nlm.nih.gov/pubmed/29938864
National Cancer Institute. Helicobacter pylori and Cancer. www.cancer.gov/about-cancer/causes-prevention/risk/infectious-agents/h-pylori-fact-sheet [Accessed Febuary 2019]