What is prevention?

Cancerprevention is action taken to lower the chance of getting cancer. By preventing cancer, the number of new cases of cancer in a group or population is lowered. Hopefully, this will lower the number of deaths caused by cancer.

To prevent new cancers from starting, scientists look at risk factors and protective factors. Anything that increases your chance of developing cancer is called a cancer risk factor; anything that decreases your chance of developing cancer is called a cancer protective factor.

Some risk factors for cancer can be avoided, but many cannot. For example, both smoking and inheriting certain genes are risk factors for some types of cancer, but only smoking can be avoided. Regular exercise and a healthy diet may be protective factors for some types of cancer. Avoiding risk factors and increasing protective factors may lower your risk but it does not mean that you will not get cancer.

Different ways to prevent cancer are being studied, including:

• Changing lifestyle or eating habits.
• Avoiding things known to cause cancer.
• Taking medicines to treat a precancerouscondition or to keep cancer from starting.

General Information About Stomach Cancer

Key Points for this Section

• Stomach (gastric) cancer is a disease in which malignant (cancer) cells form in the stomach.
• In the United States, the number of new cases of stomach cancer has stayed about the same in recent years.

Stomach (gastric) cancer is a disease in which malignant (cancer) cells form in the stomach.

The stomach is a J-shaped organ in the upper abdomen. It is part of the digestive system, which processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) in foods that are eaten and helps pass waste material out of the body. Food moves from the throat to the stomach through a hollow, muscular tube called the esophagus. After leaving the stomach, partly-digested food passes into the small intestine and then into the large intestine.

The esophagus and stomach are part of the upper gastrointestinal (digestive) system.

See the following for more information about stomach cancer:

• Stomach Cancer Screening
• Stomach Cancer Treatment

In the United States, the number of new cases of stomach cancer has stayed about the same in recent years.

In recent years, the number of new cases of stomach cancer in the United States has stayed about the same. Men are twice as likely as women to be diagnosed with stomach cancer.

Stomach cancer is the fifth most common cancer in the world.

The number of deaths from stomach cancer has decreased over many years, especially in the United States. Black men are more than twice as likely as White men to die from stomach cancer.

Stomach Cancer Prevention

Key Points for this Section

• Avoiding risk factors and increasing protective factors may help prevent stomach cancer.
• The following are risk factors for stomach cancer:
• Certain medical conditions
• Certain genetic conditions
• Diet
• Environmental causes
• The following are protective factors that may decrease the risk of stomach cancer:
• Stopping smoking
• Treating Helicobacter pylori infection
• It is not known if the following factors lower the risk of stomach cancer or have no effect on the risk of stomach cancer:
• Diet
• Dietary supplements
• Cancer prevention clinical trials are used to study ways to prevent cancer.
• New ways to prevent stomach cancer are being studied in clinical trials.

Avoiding risk factors and increasing protective factors may help prevent stomach cancer.

Avoiding cancerrisk factors may help prevent certain cancers. Risk factors include smoking, being overweight, and not getting enough exercise. Increasing protective factors such as quitting smoking and exercising may also help prevent some cancers. Talk to your doctor or other health care professional about how you might lower your risk of cancer.

The following are risk factors for stomach cancer:

Certain medical conditions

Having any of the following medical conditions may increase the risk of stomach cancer:

• Helicobacter pylori (H. pylori) infection of the stomach.
• Epstein-Barr virus (EBV) infection.
• Intestinalmetaplasia (a condition in which the cells that line the stomach are replaced by cells that normally line the intestines).
• Chronicatrophic gastritis (thinning of the stomach lining caused by long-term inflammation of the stomach).
• Pernicious anemia (a type of anemia caused by vitamin B12deficiency).
• Stomach (gastric) polyps.

Certain genetic conditions

Genetic conditions may increase the risk of stomach cancer in people with any of the following:

• A mother, father, sister, or brother who has had stomach cancer.
• Type A blood.
• Li-Fraumeni syndrome.
• Familial adenomatous polyposis (FAP).
• Hereditary nonpolyposis colon cancer (HNPCC; Lynch syndrome).

Diet

The risk of stomach cancer may be increased in people who:

• Eat a diet low in fruits and vegetables.
• Eat a diet high in salted or smoked foods.
• Eat foods that have not been prepared or stored the way they should be.

Environmental causes

Environmental factors that may increase the risk of stomach cancer include:

• Being exposed to radiation.
• Working in the rubber or coal industry.

The risk of stomach cancer is increased in people who come from countries where stomach cancer is common.

The following are protective factors that may decrease the risk of stomach cancer:

Stopping smoking

Studies show that smoking is linked with an increased risk of stomach cancer. Stopping smoking or never smoking decreases the risk of stomach cancer. Smokers who stop smoking lower their risk of having stomach cancer over time.

Treating Helicobacter pylori infection

Studies show that chronicinfection with Helicobacter pylori (H. pylori) bacteria is linked to an increased risk of stomach cancer. When H. pylori bacteria infects the stomach, the stomach may become inflamed and cause changes in the cells that line the stomach. Over time, these cells become abnormal and may become cancer.

Some studies show that treating H. pylori infection with antibiotics lowers the risk of stomach cancer. One study found that treating H. pylori infection with antibiotics, vitamins, and garlicsupplements may also lower the number of deaths from stomach cancer. More studies are needed to find out whether treating H. pylori infection with antibiotics lowers the number of deaths from stomach cancer or keeps changes in the stomach lining, that can lead to cancer, from getting worse.

One study found that patients who used proton pump inhibitors (PPIs) after treatment for H. pylori were more likely to get stomach cancer than those who did not use PPIs. More studies are needed to find out whether PPIs lead to cancer in patients treated for H. pylori.

It is not known if the following factors lower the risk of stomach cancer or have no effect on the risk of stomach cancer:

Diet

Not eating enough fresh fruits and vegetables is linked to an increased risk of stomach cancer. Some studies show that eating fruits and vegetables that are high in vitamin C and beta carotene may lower the risk of stomach cancer. Studies also show that whole-grain cereals, carotenoids, green tea, and substances found in garlic may lower the risk of stomach cancer.

Studies show that eating a diet with a lot of salt may increase the risk of stomach cancer. Many people in the United States now eat less salt to lower their risk of high blood pressure. This may be why rates of stomach cancer have decreased in the U.S.

Dietary supplements

It is not known if taking certain vitamins, minerals, and other dietary supplements helps lower the risk of stomach cancer. In China, a study of beta carotene, vitamin E, and selenium supplements in the diet showed a lower number of deaths from stomach cancer. The study may have included people who did not have these nutrients in their usual diets. It is not known if increased dietary supplements would have the same effect in people who already eat a healthy diet.

Other studies have not shown that taking dietary supplements such as beta carotene, vitamin C, vitamin E, or selenium lowers the risk of stomach cancer.

Cancer prevention clinical trials are used to study ways to prevent cancer.

Cancer preventionclinical trials are used to study ways to lower the risk of certain types of cancer. Some cancer prevention trials are done with healthy people who have not had cancer but who have an increased risk for cancer. Other prevention trials are done with people who have had cancer and are trying to prevent another cancer of the same type or to lower their chance of developing a new type of cancer. Other trials are done with healthy volunteers who are not known to have any risk factors for cancer.

The purpose of some cancer prevention clinical trials is to find out whether actions people take can prevent cancer. These may include eating fruits and vegetables, exercising, quitting smoking, or taking certain medicines, vitamins, minerals, or food supplements.

New ways to prevent stomach cancer are being studied in clinical trials.

Information about clinical trials supported by NCI can be found on NCI’s clinical trials search webpage. Clinical trials supported by other organizations can be found on the ClinicalTrials.gov website.