Cancer / 05 Aug, 2020

The Helicobacter pylori infection and stomach cancer

Dr Lau Pik Onn

What is the Helicobacter pylori infection?

This infection occurs when Helicobacter pylori (H. pylori) bacteria infects the stomach.

H. pylori is a bacteria that grows in the digestive tract and attacks the stomach lining. This bacteria can cause dyspepsia (indigestion) and complications such as peptic ulcer disease and gastric malignancies. Infected individuals have a 10-20% lifetime risk of developing peptic ulcers and a 1-2% risk of gastric cancer.

H. pylori is a common chronic bacterial infection that is present in over 50% of the world’s population, although its prevalence has been gradually declining in the Asia-Pacific region. In Singapore, the seroprevalence rate is 31%.1

Signs and symptoms of H. pylori infection

Most people with H. pylori infection do not have any symptoms. However, when signs and symptoms do occur, they include:

  • Indigestion
  • Ache or burning pain in the upper abdomen
  • Abdominal pain, worse when the stomach is empty
  • Nausea or vomiting
  • Loss of appetite
  • Frequent burping
  • Bloating or a feeling of fullness after meal
  • Unintentional weight loss

How is it spread?

The mode of transmission of H. pylori is not entirely clear. It may spread from person to person through oral-oral or faecal-oral exposure (such as from contaminated food or where there is poor sanitation).

Transmission occurs mostly within family groups in developed nations but can also be acquired from the community in developing countries.

How is the presence of H. pylori diagnosed?

Tests that are undertaken to diagnose H. pylori are:

  • Blood tests to check for antibodies against H. pylori. This test is done as part of Icon Health Screening’s comprehensive screening packages.
  • Urea breath test, which involves drinking a special solution containing a substance that is broken down by the H. pylori bacteria. The breakdown products can then be detected in a person’s breath during the test.

Treatment for H. pylori

Treatment for people with H. pylori includes a course of antibiotics and gastric medication for up to two weeks.

A urea breath test must be done at least four weeks after the end of treatment to confirm that treatment has been successful and the bacteria has been eradicated.

If you are still H. pylori positive following treatment with antibiotics or have persistent symptoms, you will be referred to a specialist for further evaluation, endoscopy and treatment.

Complications associated with H. pylori

H. pylori bacteria disturbs the protective lining in the stomach, allowing enzymes and toxins to damage the stomach cells and leaving the underlying stomach tissues more vulnerable to damage by digestive juices.

Once the bacteria has done enough damage, the acid can get through the lining of the stomach. This can lead to:

  • Inflammation of stomach lining (gastritis)
  • Peptic ulcer (gastric or duodenal ulcer) – About 10-20% of patients with H. pylori infection will develop ulcers. This can present as pain or discomfort in the upper abdomen. Bleeding ulcers can also cause dark or tar coloured stools.
  • Stomach cancer – H. pylori infection is a strong risk factor for certain types of stomach cancer

Stomach cancer (gastric cancer) is among the top 10 cancers in Singaporean men and women. It is more common in men aged above 40-years-old and in Chinese people compared to Malays and Indians.

The exact cause of stomach cancer is unknown but there are some risk factors including:

  • Chronic infection by the H. pylori bacteria – This forms the single most important risk factor
  • Family history of stomach cancer
  • Hereditary stomach polyps
  • Smoking
  • Diets high in smoked foods, pickled foods, and salted fish and meat

Why is screening important?

As most people with H. pylori infection do not have symptoms, the increasing use of H. pylori testing during health screening has helped further investigation and treatment of the infection.

H. pylori is a major risk factor for the development of peptic ulcer disease and stomach cancers, which is why treatment and successful eradication of the bacteria is so important.

References

For a full list of references, click here.
  1. Ang TL, Fock KM, Ang D, Kwek AB, Teo EK, Dhamodaran S. The Changing Profile of Helicobacter pylori Antibiotic Resistance in Singapore: A 15-Year Study. Helicobacter. 2016;21(4):261‐265. doi:10.1111/hel.12291
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