Stomach cancer or gastric cancer occurs in the lining of the stomach. The cancer cells form and grow into a tumor. The tumor grows slowly over time.

Cases of stomach cancer have been declining in the country over the past 60 years. In the 1930s, stomach cancer caused the highest number of cancer deaths in the U.S. The mortality rate has significantly reduced over time. Further statistics show that the incidence of adenocarcinoma, the cancer that occurs in the mucosal lining of the stomach, has been decreasing. But the cancer of the cardia (the junction of the esophagus and the upper part of the stomach that contain the cardiac glands) has become more common.

In 2018, about 1.5% of all cancer cases were of stomach cancer. The mortality rate was about 1.8% of all cancer deaths. Compared to Central and South America, Southern and Eastern Europe, China and Japan, North America has a lesser incidence of the disease.

As in most cases of cancer, the exact cause is not known. In the case of stomach cancer, there are factors that are known to raise the risk:

• Gastritis – inflammation of the stomach
• Pernicious Anemia – a specific type of anemia that is long-lasting
• H. pylori Infection – Infection caused by Helicobacter pylori, a common stomach bacterium
• Previous stomach surgery

About 60% of stomach cancer cases are caused by certain types of H. pylori bacteria; however, only 2% of the people with H. pylori infections develop stomach cancer. There are a number of other factors that are known to increase the chances of contracting stomach cancer:

• Heredity – Parents, siblings, or children who have had stomach cancer
• Genetics – cell mutation, gene mutation, immune system disorder like common variable immune deficiency (CVID), Lynch syndrome, Hereditary diffuse gastric cancer
• Blood Type – Type A blood is more susceptible to cancer
• Virus Infection – any infection caused by the Epstein Barr virus, also known as Human gammaherpesvirus 4, a member of the herpes virus family
• Gender, age, and ethnicity – men of advanced age, and Native Americans, African Americans, Hispanic Americans, and Pacific Islanders, and those belonging to low socioeconomic status
• Exposure – to asbestos and other pollutants in the metal, timber, coal, and rubber industries
• Smoking
• Obesity
• Diet – high in salty, pickled, and smoked foods, and low in fresh vegetables, and fruit
• Types of stomach and intestine polyps – adenomatous polyps or adenomas and hamartomas
• Stomach lymphoma or mucosa-associated lymphoid tissue (MALT) lymphoma
• Menetrier Disease – or hypertrophic gastropathy, which refers to large folds in the stomach lining caused by excess growth of the lining

Early signs of stomach cancer include:

Early signs of stomach cancer are nonspecific and vague and include loss of appetite, feeling full after a small meal, feeling bloated after a meal, nausea, indigestion, and heartburn. Though some of these symptoms may not indicate stomach cancer, it is best to get a cancer screening done.

As the cancer progresses, the number of symptoms increase and become serious:

• Weakness and fatigue
• Difficulty swallowing
• Unexplained weight loss
• Skin or eyes turning yellow
• Persistent heartburn
• Stomach pain
• Swelling of the stomach
• Severe nausea
• Persistent vomiting, including blood
• Diarrhea or constipation
• Blood in the stool
• Iron-deficiency anemia