CancerQuest | Gastric Cancer: Risk Factors

Factors that influence risk of developing stomach (gastric) cancer:

Helicobacter pylori infection
Diet
Gender
Age
Ethnicity
Geography
Smoking
Obesity

Previous stomach surgery
Pernicious anemia
Menetrier disease
Type A blood
Family history of stomach cancer
Occupations
Epstein-Barr infection
Some stomach polyps

The relative effects of these and other risk factors in any given case of cancer is variable and very difficult to determine with accuracy at this time. Some of these and other risk factors are discussed on the following pages.

Helicobacter pylori infection

H. pylori is one of the most common bacterial infections worldwide. It causes duodenal and gastric ulcers as well as chronic gastritis. H. pylori significantly increases the risk of developing gastric adenocarcinoma. The World Health Organization classifies H. pylori as a class I carcinogen. It is found in the stomach of over half of the world's population. The bacteria live in the mucosal lining of the stomach and can cause chronic inflammation(gastritis). This inflammation can lead to DNA damage that promotes cancer development. H. pylori is associated with over 70% of gastric adenocarcinomas.

Eradication of the infection is the best way to prevent gastric cancer. A combination of antibiotics, stomach acid suppressors and stomach protectors may be used. Unfortunately, adequate diagnostic tests and drug therapy for H. pylori eradication is very expensive. A vaccine would be a better approach to the H. pylori problem. Vaccines have been moderately successful in animal models, but not in humans. Several types of vaccines are currently being studied.⁽¹⁾

Diet

An increase of fiber, raw fruit and vegetable consumption is associated with a significant decrease of gastric cancer risk. Consumption of nitrates, refined carbohydrates (white bread, white rice, sugary cereal, etc.) and highly salted or pickled foods is suspected to increase the risk for gastric cancer.⁽¹⁾

Gender

Men are at higher risk than women for gastric cancer. This is especially true for the intestinal type of cancer. It is thought that female reproductive hormones such as estrogen and progesterone help protect against gastric cancer development.⁽²⁾⁽³⁾

Age

The risk for developing gastric cancer gradually increases after the age of 40. The diffuse type gastric cancer occurs more often in younger patients whereas the intestinal type occurs more often in the elderly. For this reason, age is a greater risk factor for the intestinal type than for the diffuse type.⁽²⁾

Ethnicity and Geography

Caucasians are at the lowest risk of developing gastric cancer and people of Asian descent are at the highest risk. This disparity is mainly due to diet and living conditions. Japan and China have the highest rates of gastric cancer and H. pylori infection. Eastern Europe is also at a higher risk than North America and Western and Northern Europe.⁽²⁾⁽⁴⁾

Smoking

Studies have shown that smoking increases risk for gastric cancer. Asian smokers have a higher risk for developing intestinal type gastric cancer whereas Western smokers are at higher risk for diffuse type gastric cancer.⁽²⁾

Family History of Gastric Cancer

Cancer cases can be grouped into two broad categories, sporadic and familial. Sporadic cancers are those in which the affected individual does not have a known family history of the disease. Familial cancers tend to occur in several generations of a family and affected individuals often have close relatives (brother, sister, father) with the same type of cancer. It is possible that these individuals inherit genes that increase risk for the development of specific cancers. Individuals with a family history of gastric cancer are at an increased risk of developing the disease. The increase in risk depends upon the type of relative affected. The more closely related an individual is to someone who has/had gastric cancer, the more likely they will share the associated genes. Inherited gastric cancer accounts for about 1-3% of all stomach cancer cases⁽⁵⁾.

The major gastric cancer susceptibility syndrome is called hereditary diffuse gastric cancer (HDGC). Other inherited forms of digestive system cancer include familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC):

Hereditary diffuse gastric cancer (HDGC): HDGC is an autosomal dominant disorder and is caused by a mutation in the CDH1 gene. The mutation results in a decrease in type 1 E-cadherin. This decreased expression appears to be the difference between diffuse and intestinal gastric cancer. The onset of cancer is widely variable for these individuals, from 16-82 years of age. Genetic testing is available for this syndrome.⁽⁶⁾ Learn more about FAP and HNPCC.