- Researchers say about three-quarters of gastric cancer cases worldwide are caused by the common bacterium Helicobacter pylori.
- H. pylori infection doesn’t always produce symptoms, so it’s important to get screened for any persistent gastric-related pain, such as indigestion and bloating.
- You can lower your risk of gastric cancer by eating a healthy diet, exercising regularly, and getting tested for H. pylori if you have any symptoms that may indicate infection.
The vast majority of stomach cancer cases have been linked to a common bacteria that often doesn’t produce any symptoms.
The scientists found that nearly 16 million people born between 2008 and 2017 are expected to develop gastric cancer sometime during their lifetime. Of those cases, around 12 million will be caused by H. pylori bacteria.
They noted that about 8 million of those bacteria-related cases are expected to occur in Asia. Another 1.5 million are predicted for North America and South America.
They also noted that a vaccine to prevent H. pylori bacteria “would be a powerful tool for gastric cancer prevention,” but there appears to be “little momentum at present to advance its development.”
Experts not involved in the study told Healthline the findings are important and should be noted by medical professionals.
“This is truly a fascinating, practice-changing study,” said Anton Bilchik, MD, a surgical oncologist as well as the chief of medicine and director of the Gastrointestinal and Hepatobiliary Program at Providence Saint John’s Cancer Institute in Santa Monica, CA. “This tells us that … it is a preventable cancer.”
“We have known that H. pylori infection increases an individual’s risk of developing stomach cancer for many years,” added Joo Ha Hwang, MD, a professor of medicine at Stanford University.
“This study quantifies the estimated number of deaths that would likely occur if we do not start screening individuals who are at moderate to high risk for H. pylori infection and gastric cancer. This study is a call to action to address a preventable cancer,” Hwang noted.
Alan Venook, MD, a professor of medical oncology and translational research at the University of California San Francisco, and program development director at the Helen Diller Family Comprehensive Cancer Center, said the connection between the H. pylori bacteria and gastric cancer has been known for more than 30 years.
He cited older research from 1991 published in the New England Journal of Medicine that first made the connection, and said the findings in the new study aren’t surprising. Still, he expressed concern over the persistent nature of the bacteria’s connection to cancer.
“The most interesting thing in this study to me is that this is still a problem,” Venook said, adding he is “mystified” as to why progress hasn’t been made. “I think the message to medical professionals is that this remains a terrible problem,” he noted. “This is a wake-up call.”
Bilchik, who had attended the 1991 presentation of the original study, said the research was initially dismissed by the medical community. Since then, he said those early findings have proven to be correct.
“This is a clear message to both patients and professionals that stomach cancer is not necessarily caused by smoking and alcohol,” he said.
Nilesh Vora, MD, a hematologist and medical oncologist and medical director of the MemorialCare Todd Cancer Institute at Long Beach Medical Center in California, has some cautions about the new research.
He called it “thought-provoking,” but added that more research is necessary to confirm the data and the conclusions.
The Helicobacter pylori bacteria grow in the digestive tract and tend to attack the stomach lining. It has adapted itself to live in the highly acidic world of the human gastrointestinal system.
H. pylori often develops in a person’s stomach during childhood. The bacteria are typically harmless and don’t cause symptoms. However, in some cases, they may lead to stomach ulcers and some diseases, including gastric cancer.
Many people with H. pylori don’t have symptoms. However, an estimated 30% of people with the bacteria develop peptic ulcers and other conditions.
Some common symptoms from the bacteria include:
- burning stomach pain
- feeling full quickly
- nausea
- burping
- unexplained weight loss
The bacteria can be transmitted via saliva, contaminated food, and other methods. It can be diagnosed with tests involving breath, stool samples, and blood antibodies. Doctors sometimes order an endoscopy, which involves placing a tube down a person’s throat.
The bacteria are treated with antibiotics. Some people may be prescribed proton pump inhibitors to help the stomach heal.
The American Cancer Society (ACS) notes there are currently
“Given the relatively low prevalence of gastric cancer in the United States, there is currently no screening recommendation for H. pylori in patients without symptoms,” said Anu Agrawal, MD, vice president of Global Cancer Support at the American Cancer Society.
“The high incidence in Asia particularly could justify screening protocols which, as noted in the publication, have been initiated in a few Asian countries,” he told Healthline.
Bilchik said that people should not ignore gastrointestinal symptoms that linger for an extended period of time. “If the symptoms are persistent, then go to a physician and be proactive,” Bilchik advised.
Vora added that while screenings are important, there are some logistical issues. Endoscopies, he said, are invasive and expensive. He added that the big questions are whether general screenings should be done for this bacterium and whether everyone with long-term gastrointestinal symptoms should be tested for H. pylori.
Hwang agreed that screening should be selective.
“H. pylori often infects family members, so if one family member is diagnosed with H. pylori, family members who live together should be tested for the infection,” he said.
“We have been advocating for individuals who have immigrated from regions that have a high incidence of H pylori infection and gastric cancer, such as East Asia, Eastern Europe, and the west coast of South America, to be tested for H pylori infection and treated if positive.”
The National Cancer Institute (NCI)
Those numbers represent less than 2% of all cancer cases and all cancer deaths in the United States.
Almost 38% of people in the United States with stomach cancer are expected to live at least five years after diagnosis.
Stomach cancer usually develops over a number of years. Many times, there are no symptoms until the cancer has spread to other parts of the body.
The disease is more common in adults over the age of 60 and in those who smoke, have obesity, or have a family history of the disease. It’s also more common in people of Asian descent and people with a diet high in salty foods, meat, and processed products.
Symptoms of stomach cancer include:
- frequent heartburn
- loss of appetite
- bloating or burping
- indigestion
- abdominal pain
The disease can be treated with chemotherapy, radiation, surgery, and immunotherapy.
Experts say you can lower your risk of stomach cancer by:
The American Cancer Society has a
“Obesity, tobacco use, alcohol, diets high in smoked foods or foods preserved by salting, or diets low in fruits and vegetables are risk factors,” said Agrawal. “If you have a family history of stomach cancer, are a first-generation immigrant from a high prevalence area (e.g., East Asia), or have certain genetic cancer predisposition syndromes, you should be screened for stomach cancer.”
Vora said the message is pretty simple: “Eat well and exercise more.”
