Stomach Cancer Overview

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Causes, Risk Factors, and Prevention TOPICS

What are the risk factors for stomach cancer?

A risk factor is anything that affects a person’s chance of getting a disease such as cancer. Different cancers have different risk factors. Some risk factors, such as smoking, can be changed. Others, like a person’s age or family history, can’t be changed. But risk factors don’t tell us everything. Having a risk factor, or even several risk factors, does not mean that you will get the disease. And many people who get the disease may have few or no known risk factors.

Risk factors for stomach cancer

Scientists have found some risk factors that make a person more likely to develop stomach cancer.

Gender: Stomach cancer is more common in men than in women.

Age: There is a sharp increase in stomach cancer after age 50. Most people are between their late 60s and 80s when their cancer is found.

Ethnicity: In the United States, stomach cancer is more common in Hispanic Americans, African Americans, and Asian Pacific Islanders than it is in non-Hispanic whites.

Where a person lives: Worldwide, stomach cancer is more common in Japan, China, Southern and Eastern Europe, and South and Central America. This disease is less common in Northern and Western Africa, South Central Asia, and North America.

Bacterial infection: Infection with bacteria called Helicobacter pylori (H. pylori) seems to be a major cause of stomach cancer. Long-term infection with this germ may lead to inflammation and pre-cancer changes to the inner layer of the stomach. This germ is also linked to ulcers and some types of lymphoma of the stomach. But most people who carry this germ in their stomachs never get cancer.

Stomach lymphoma: People who have been treated for a certain type of stomach lymphoma known as MALT lymphoma have an increased risk of adenocarcinoma of the stomach. This is probably because this stomach lymphoma is caused by infection with H. pylori.

Diet: An increased risk of stomach cancer is seen in people with diets high in smoked foods, salted fish and meats, and pickled vegetables. On the other hand, eating lots of fresh fruits and vegetables seems to lower the risk of stomach cancer.

Tobacco use: Smoking about doubles the risk of stomach cancer.

Being overweight or obese: Being overweight or obese (very overweight) is a possible cause of cancers of the upper part of the stomach, but the strength of this link is not yet clear.

Earlier stomach surgery: Stomach cancer is more likely to be found in people who have had part of their stomach removed to treat other problems like ulcers. These cancers can happen many years after the surgery.

Pernicious anemia: In this disease, the stomach doesn’t make enough of a protein that allows the body to absorb vitamin B12 from foods. This can lead to a shortage of red blood cells (anemia) and other problems. Patients with this disease also have an increased risk of stomach cancer.

Menetrier disease: This rare disease involves changes in the stomach lining that might be linked to a risk of stomach cancer.

Type A blood: For unknown reasons, people with type A blood have a higher risk of getting stomach cancer.

Inherited cancer syndromes: A syndrome is a cluster of symptoms that point to a disease or condition. A number of syndromes that result from gene changes (mutations) inherited from a parent can increase the risk of stomach cancer in people who have them. These syndromes include:

  • Hereditary diffuse gastric cancer
  • Hereditary non-polyposis colorectal cancer (HNPCC)
  • Familial adenomatous polyposis (FAP)
  • Hereditary breast and ovarian cancer syndrome
  • Li-Fraumeni syndrome
  • Peutz-Jeghers syndrome

To find out more about these syndromes, please see the section “What are the risk factors for stomach cancer?” in our document, Stomach Cancer.

Family history: People with close family members (parents, siblings, and children) who have had stomach cancer are more likely to get this disease.

Some types of stomach polyps: Polyps are benign growths on the lining of the stomach. Most polyps do not increase the risk of stomach cancer. But one type (called adenomatous polyps or adenomas) sometimes change into stomach cancer.

Epstein-Barr virus: This virus causes “mono” (infectious mononucleosis). It has been found in the stomach cancers of some people. Almost all adults have had this virus at some time in their lives, often as children or teens. It isn’t yet clear if this virus causes stomach cancer, just that the virus has been found in stomach cancer cells.

Certain types of work: Workers in the coal, metal, and rubber industries seem to have a higher risk of getting stomach cancer.

Immune weakness: People with an immune problem called common variable immunodeficiency (CVID) have an increased risk of stomach cancer. The immune system of someone with CVID can’t make enough antibodies in response to germs. People with CVID have frequent infections as well as other problems. They are also more likely to get gastric lymphoma and stomach cancer.

While there are many risk factors for stomach cancer, we do not know exactly how these factors cause cells of the stomach to become cancer. Scientists are trying to learn how and why certain changes take place in the lining of the stomach and what part H. pylori plays in stomach cancer.

They are also looking at how gene changes (mutations) can cause normal stomach cells to change and form cancers. Most of the gene changes that are linked to stomach cancer take place after birth. Very few are inherited.


Last Medical Review: 03/18/2013
Last Revised: 02/11/2014