Types of Stomach Cancer
- Cancer that begins in hormone-producing cells (carcinoid cancer)
Hormone-producing cells can develop carcinoid cancer. Carcinoid cancer in the stomach is rare. - Cancer that begins in immune system cells (lymphoma)
The walls of the stomach contain a small number of immune system cells that can develop cancer. Lymphoma in the stomach is rare. - Cancer that begins in nervous system tissues
A gastrointestinal stromal tumor (GIST) begins in specific nervous system cells found in your stomach. GIST is a rare form of stomach cancer. - Cancer that begins in the glandular cells (adenocarcinoma)
The glandular cells that line the inside of the stomach secrete a protective layer of mucus to shield the lining of the stomach from the acidic digestive juices. Adenocarcinoma accounts for the great majority of all stomach cancers.
Do we know what causes stomach cancer?
There are many known risk factors for stomach cancer, but it is not known exactly how these factors cause cells of the stomach lining to become cancerous. This is the subject of ongoing research. Several changes thought to be pre-cancerous can occur in the stomach lining.In chronic atrophic gastritis, the normal glands of the stomach are either decreased or absent. There is also some degree of inflammation (the stomach cells are damaged by cells of the immune system). Atrophic gastritis is often caused by H pylori infection. It can also be caused by an autoimmune reaction, in which a person’s immune system attacks the cells lining the stomach. Some people with this condition go on to develop pernicious anemia or other stomach problems, including cancer. It is not known exactly how this condition might progress to cancer. Stomach Cancer Causes
Another possible pre-cancerous change is intestinal metaplasia. In this condition, the normal lining of the stomach is replaced with cells that closely resemble the cells that usually line the intestine. People with this condition usually have chronic atrophic gastritis as well. How and why this change occurs and progresses to stomach cancer is not well understood. This might also be related to H pylori infection.
Recent research has provided clues on how some stomach cancers form. For instance, H pylori bacteria, particularly certain subtypes, can convert substances in some foods into chemicals that cause mutations (changes) in the DNA of the cells in the stomach lining. This may also explain why certain foods such as preserved meats increase a person’s risk for stomach cancer. On the other hand, some of the foods that might lower stomach cancer risk, such as fruits and vegetables, contain antioxidants that can block substances that damage a cell’s DNA.
How stomach cancer spreads?
There are three ways stomach cancer can spread:- Directly
The cancer can spread from the stomach into nearby tissues and organs, such as the pancreas, colon, small intestine and peritoneum (the lining of the inside of the abdominal cavity). - Through the lymphatic system
The lymphatic system is a series of glands (nodes) located throughout your body, similar to the blood circulatory system; glands produce many specialised cells needed by your immune system to fight infection. - Through the blood
Which can cause the cancer to spread from the stomach to other parts of the body, most commonly the liver.