Understanding your risk and recognizing potential signs of stomach cancer can help you make informed decisions about your health. Having one or more risk factors does not mean you will develop stomach cancer, and some people who develop the disease have few or no known risk factors. Knowing what may increase your risk and when to talk with a healthcare professional is an important part of digestive health awareness.
Learn more from the National Cancer Institute: Stomach Cancer Causes and Risk Factors and the American Cancer Society: Stomach Cancer Risk Factors.
Understanding Stomach Cancer Risk
Stomach cancer develops when changes in stomach cells affect how they grow and divide. Researchers have identified several factors that can increase a person’s likelihood of developing the disease. Some, such as tobacco use, can be changed, while others, including age, family history, and inherited genetic conditions, cannot.
H. pylori Infection
Chronic infection with Helicobacter pylori (H. pylori) is a major risk factor for stomach cancer, particularly cancers that develop in the lower and middle parts of the stomach. The bacterium infects the stomach lining and can cause chronic inflammation and atrophic gastritis. In some people, these changes may progress over time and contribute to stomach cancer development.
Most people with H. pylori infection will not develop stomach cancer. However, treatment of H. pylori infection reduces the risk of certain types of stomach cancer.
Learn more from the National Cancer Institute: H. pylori and Cancer.
H. pylori, the Gastric Microbiome & Stomach Cancer Risk
Long-term infection with Helicobacter pylori (H. pylori) is a major risk factor for stomach cancer. The bacterium infects the stomach lining and can cause chronic inflammation and changes that, over time, may contribute to cancer development. Most people with H. pylori will not develop stomach cancer, but identifying and treating the infection can reduce the risk of certain types of stomach cancer.
Research is also expanding what we know about the relationship between bacteria and stomach cancer.
Looking Beyond H. pylori: Emerging Research on the Gastric Microbiome
The stomach is home to a diverse community of microorganisms known as the gastric microbiome. While H. pylori remains a well-established risk factor for stomach cancer, emerging research suggests that the relationship between bacteria and gastric cancer is more complex than the effects of a single organism alone.
Research highlighted by the American Association for Cancer Research (AACR) describes a possible shift toward understanding gastric cancer as a polymicrobial disease, in which microbial imbalance, or dysbiosis, and interactions among H. pylori and other bacteria may contribute to inflammation, tissue damage, precancerous changes, and tumor development. Studies discussed by AACR have identified bacteria including Streptococcus anginosus, Fusobacterium nucleatum, and Prevotella melaninogenica as organisms of interest in this emerging research.
Researchers are also studying whether changes in the gastric microbiome could eventually help identify people at higher risk for stomach cancer. AACR notes that microbial biomarkers found in the stomach, saliva, gastric fluids, or stool may one day support earlier detection and more accurate risk assessment, although these approaches remain under investigation and are not yet standard screening tools.
[Read AACR’s “Gastric Cancer: Looking Beyond H. pylori”]
DDF-Supported Research: Understanding H. pylori
Through a Debbie’s Dream Foundation–AACR Gastric Cancer Research Fellowship, Valerie O’Brien, PhD, used DDF-AACR grant support to develop a mouse model of H. pylori-driven gastric cancer and study how the infection changes stomach cells at the molecular level.
Her research has examined H. pylori-driven inflammation and precancerous cellular changes, helping researchers better understand how infection may contribute to gastric cancer development. The work may also inform future efforts to identify detectable markers of disease and develop new treatment approaches.
Learn more about Dr. O’Brien’s DDF-AACR-supported research from AACR.
Together, this growing body of research reinforces an important message: understanding H. pylori remains critical to stomach cancer prevention, while emerging science is expanding our understanding of the broader microbial environment in which gastric cancer may develop.
Family History & Genetics
Having a first-degree relative—a parent, sibling, or child—who has had stomach cancer increases your risk. Certain inherited cancer syndromes can also substantially increase the likelihood of developing the disease.
These include diffuse gastric and lobular breast carcinoma syndrome, previously known as hereditary diffuse gastric cancer (HDGC). This rare inherited syndrome is most often associated with pathogenic changes in the CDH1 gene and can also involve CTNNA1.
Other inherited syndromes associated with increased stomach cancer risk include Lynch syndrome, familial adenomatous polyposis (FAP), Peutz-Jeghers syndrome, Li-Fraumeni syndrome, juvenile polyposis syndrome, gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS), and others.
If stomach cancer or certain other cancers occur frequently in your family, particularly at younger ages, talk with a healthcare professional or genetic counselor about whether genetic risk assessment may be appropriate.
Learn more from the National Cancer Institute: Stomach Cancer Causes and Risk Factors.
Changes and Conditions Affecting the Stomach
Certain medical conditions and changes affecting the stomach can increase stomach cancer risk. These include:
- Chronic atrophic gastritis
- Gastric intestinal metaplasia
- Pernicious anemia
- Certain types of stomach polyps
- Previous stomach surgery
- Gastroesophageal reflux disease (GERD), particularly in relation to cancers of the upper stomach
- Epstein-Barr virus infection
- Rare conditions such as Ménétrier disease
People with these conditions should discuss their individual risk and any appropriate follow-up with their healthcare team.
Sources: National Cancer Institute and American Cancer Society.
Age, Sex, Race & Ethnicity
Stomach cancer can occur at any age, but risk increases as people get older. The disease is also more common among men than women.
In the United States, stomach cancer occurs more often among Black, Hispanic, Asian or Pacific Islander, and American Indian or Alaska Native populations than among White populations. The reasons for these differences are complex and remain an important area of research.
Learn more from the National Cancer Institute.
Diet, Tobacco & Other Factors
Additional factors associated with increased stomach cancer risk include:
- Tobacco use
- Excess body weight, particularly for cancers of the upper stomach
- Diets high in salted, smoked, or poorly preserved foods
- Heavy alcohol use
- Certain occupational exposures, including work in the coal, metal, or rubber industries
- Exposure to very high levels of radiation
No single food, behavior, or lifestyle factor determines whether someone will develop stomach cancer. Risk can reflect many factors that interact over a person’s lifetime.
Sources: National Cancer Institute and American Cancer Society.
Signs & Symptoms of Stomach Cancer
Stomach cancer may cause no noticeable symptoms early in the disease. When symptoms do occur, they can resemble common digestive problems, which can make stomach cancer difficult to recognize.
Possible signs and symptoms include:
- Persistent indigestion or heartburn
- Stomach pain or discomfort
- Feeling bloated after eating
- Feeling full after eating only a small amount
- Loss of appetite
- Nausea or vomiting
- Unexplained weight loss
- Difficulty swallowing
- Blood in the stool
- Vomiting blood
- Fatigue or weakness related to anemia
- Abdominal swelling or fluid buildup
- Jaundice, particularly if cancer has spread to the liver
Learn more from the National Cancer Institute: Stomach Cancer Symptoms and the American Cancer Society: Signs and Symptoms of Stomach Cancer.
When Should You Talk With a Healthcare Professional?
Having one or more of these symptoms does not mean you have stomach cancer. Many are much more commonly caused by other digestive conditions.
However, symptoms that persist, worsen, recur, or cannot be explained should be discussed with a healthcare professional. Be prepared to share when your symptoms began, how often they occur, and whether you have any personal or family risk factors.
If you are concerned about your risk for stomach cancer, even if you do not have symptoms, talk with your healthcare professional about your family history, medical history, and whether additional evaluation may be appropriate.
Understanding Risk Is the First Step
Knowing your risk can help you have more informed conversations about your health. Learn more about how stomach cancer may be identified earlier, who may benefit from additional evaluation, and the role of H. pylori testing, genetic risk assessment, and other approaches to prevention and early detection.