More than 40 years ago, two Australian scientists, Dr. Barry Marshall and Dr. Robin Warren, made a discovery that changed medicine forever.
In 1982, they found a spiral-shaped bacterium living in the human stomach called Helicobacter pylori, or H. pylori for short.
This tiny germ was unusual because it could survive in the stomach’s harsh, acidic environment—a place most bacteria cannot live. Their work proved that this bacterium was the main cause of stomach ulcers and even some stomach cancers.
At the time, many doctors believed that stress or spicy food caused ulcers. To prove everyone wrong, Dr. Marshall did something shocking—he drank a solution filled with H. pylori. Soon after, he developed gastritis, a painful stomach inflammation, showing that the bacteria really could cause disease.
Thanks to this bold experiment, antibiotics became the main treatment for ulcers, saving millions of lives. The pair won the Nobel Prize in Medicine in 2005 for their groundbreaking discovery.
Decades later, scientists are still trying to understand how H. pylori affects long-term health. Researchers at National Taiwan University College of Medicine recently asked a new question: could testing for H. pylori in stool samples help find people at higher risk of stomach cancer?
Their study, published in the journal JAMA, explored whether combining a stool test for H. pylori (called the HPSA test) with a common colon cancer test (called FIT) could improve cancer screening results.
Stomach cancer, also called gastric cancer, is rare in Western countries but still a serious problem in Asia, especially in Japan and Taiwan. Around the world, H. pylori–related stomach cancer ranks as the third leading cause of cancer death, with about 800,000 new cases each year.
Experts estimate that around 90% of stomach cancer cases are linked to H. pylori infection. The World Health Organization even classifies H. pylori as a “Class 1 carcinogen,” meaning there is strong evidence that it can cause cancer.
The Taiwanese research team, led by Dr. Yi-Chia Lee, studied more than 150,000 adults between the ages of 50 and 69. About 63,000 people took both the HPSA and FIT tests, while around 89,000 took only the FIT test.
The FIT test is normally used to detect hidden blood in stool, which can indicate colon cancer, but it can sometimes help spot stomach cancer too. The researchers wanted to see if adding the HPSA test would make screening more effective.
H. pylori is a tricky germ. It infects about half of all people worldwide, yet most of them never get sick. Whether someone develops ulcers or cancer depends on many things—like genetics, diet, and environment.
The bacteria survive stomach acid by making an enzyme called urease, which creates a more neutral, less acidic environment. Over time, this can lead to chronic inflammation and damage the stomach lining, raising the risk of cancer.
Doctors often treat H. pylori with a combination of antibiotics and medicines called proton pump inhibitors (PPIs). PPIs reduce stomach acid, which helps antibiotics work better. But too much antibiotic use can cause resistance, so doctors have to choose treatment carefully.
In the Taiwan study, the group that took both the HPSA and FIT tests had a slightly lower rate of stomach cancer (0.032%) compared with the FIT-only group (0.037%).
However, the death rates were almost the same—0.015% for the combined group and 0.013% for the FIT-only group. In other words, adding the HPSA test didn’t make a big difference in how many people developed or died from stomach cancer.
When the scientists adjusted for participation and follow-up time, they found a small reduction in cancer cases but still no meaningful drop in deaths. This shows that H. pylori screening is complicated—because even though the bacteria are common, only a small number of people ever develop cancer from it.
The researchers say that more studies are needed to improve screening and understand who is most at risk. Factors such as ethnicity, diet, and lifestyle may explain why H. pylori leads to cancer in some people but not others. For now, the study reminds us that while H. pylori testing can help detect infection, it is not yet a reliable way to prevent stomach cancer on its own.
Future studies may find better ways to use genetic or lifestyle information to predict risk more accurately. But what’s clear is that managing H. pylori infection remains an important step in protecting stomach health and reducing the global burden of cancer.
If you care about cancer, please read studies that a low-carb diet could increase overall cancer risk, and vitamin D supplements could strongly reduce cancer death.
For more information about health, please see recent studies about how drinking milk affects the risks of heart disease and cancer and results showing higher intake of dairy foods linked to higher prostate cancer risk.
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