Types of Stomach Cancer
How many types of stomach cancer exist? Where it is most common? Stomach cancer is extremely common worldwide but not in US. Several types of stomach cancer exist. The type of stomach cancer depends on the start point of the tumor. The information bellows gives a glimpse on the types and locations of stomach cancer.
Scientists divide gastric cancer into two main classes: gastric cardia cancer (cancer of the top inch of the stomach, where it meets the esophagus) and non-cardia gastric cancer (cancer in all other areas of the stomach).
Stomach cancer starts in the lining of the stomach like an ulcer. More often, stomach cancers are gastric carcinomas, and they are divided into several subtypes. Lymphomas and mesenchymal tumors can also develop in the stomach.
Types of Stomach Cancer / Inflammation / Bacteria
- May be prompted from long-lasting inflammation and irritation in the lower portion of the stomach
- Associated with chronic infection of Helicobacter pylori (H. pylori)– Bacterial Infection
- Found more often in developed countries
What is Helicobacter pylori?
Helicobacter pylori is a spiral-shaped bacterium that grows in the mucus layer that coats the inside of the human stomach. To survive in the harsh, acidic environment of the stomach, Helicobacter pylori secretes an enzyme called urease, which converts the chemical urea to ammonia. The production of ammonia around H. pylori neutralizes the acidity of the stomach, making it more hospitable for the bacterium. In addition, the helical shape of Helicobacter pylori allows it to burrow into the mucus layer, which is less acidic than the inside space, or lumen, of the stomach. H. pylori can also attach to the cells that line the inner surface of the stomach. Although immune cells that normally recognize and attack invading bacteria accumulate near sites of Helicobacter pylori infection, they are unable to reach the stomach lining. In addition, H. pylori has developed ways of interfering with local immune responses, making them ineffective in eliminating this bacterium.
H. pylori has coexisted with humans for many thousands of years, and infection with this bacterium is common. The Centers for Disease Control and Prevention estimates that approximately two-thirds of the world’s population harbors the bacterium, with infection rates much higher in developing countries than in developed nations.
Although H. pylori infection does not cause illness in most infected people, it is a major risk factor for peptic ulcer disease and is responsible for the majority of ulcers of the stomach and upper small intestine. More information about H. pylori and peptic ulcer disease is available from the National Institute of Diabetes and Digestive and Kidney Diseases.
In 1994, the International Agency for Research on Cancer classified H. pylori as a carcinogen, or cancer-causing agent, in humans, despite conflicting results at the time. Since then, it has been increasingly accepted that colonization of the stomach with H. pylori is an important cause of gastric cancer and of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Infection with H. pylori is also associated with a reduced risk of esophageal adenocarcinoma.
H. pylori is thought to spread through contaminated food and water and through direct mouth-to-mouth contact. In most populations, the bacterium is first acquired during childhood. Infection is more likely in children living in poverty, in crowded conditions, and in areas with poor sanitation.
Other Types of Stomach Cancer
- May be found in the upper part of the stomach
- May extend into the gastroesophageal junction – Where the esophagus joins the stomach
- Associated with obesity
- May be prompted by gastroesophageal reflux disease
- Found more in the US than other parts of the world
- Starts in the cells of the stomach wall
- Cancer cells grow rapidly
- Scattered and diffuse widely. Hence, difficult for diagnostic
- Affects more often younger people with a family history of the disease
- The start point of this tumor in the stomach muscle or connective tissue
- May be malignant or benign – Cancerous or none cancerous
- May be found anywhere in the digestive tract
Originates from the cells producing hormone in the stomach
Originates from immune cells in the stomach
Starts in fat cells and deep soft tissues