Le stomach cancer, also called gastric cancer, develops from a parietal cell (cell in the wall of the stomach), initially normal, which multiplies in an anarchic fashion, to form a mass called malignant tumor.

Over 90% of tumors that cause stomach cancer are adenocarcinomas, that is, they develop from the inner superficial layer of the stomach, called mucous. It is a cancer that progresses slowly and that is rarely seen before the age of 50.

The tumors can remain local for a long time, before spreading to other layers of the gastric wall and invading adjacent organs (pancreas, colon, spleen) or by lymphatic and vascular route, leaving cancer cells to invade the lymph nodes, then disseminate these cancer cells in other organs such as the liver, and the lung (metastasis).

Other forms of stomach cancer, such as gastric lymphoma (which affects the lymphatic system), sarcoma (which affects muscle tissue) or gastrointestinal stromal tumor (which begins in the tissues of organs that support the digestive system), are much rarer. It will not be discussed in this sheet.

Causes

There is no specific cause for stomach cancer, but the inflammation chronic mucous membrane lining the stomach increases the risk, as in the case of gastritis Helicobacter Pylori.. Stomach cancer is also associated with the consumption, over a long period, of salty, smoked or pickled foods, with a diet low in fruits and vegetables, as well as with smoking.

Evolution

The more stomach cancer is diagnosed early, the better the chances of recovery. When it is still limited to the lining of the stomach, more than 50% of those affected will survive it for more than 5 years. If it has spread through the lymphatic system, muscle layers, or other organs, the 5-year survival rate is less than 10%.

Who is affected?

Its incidence is uneven. Across the world, stomach cancer remains the 2^st cause of death from cancer, but is the 4^st cause in Europe where it has been in decline for 20 years. This decrease in frequency concerns cancer of the “distal stomach”, the antrum and the body. For “proximal cancer” of the cardia, this is controversial because several studies suggest an increase in its incidence.

This cancer is more frequent in populations with precarious socio-economic conditions, or who rely heavily on secret and smoking for food preservation. Japan, (1/1000 inhabitant,) China and Korea are among the most affected countries.

In France the incidence is 12/100 in men and 000/4 in women. In 100 there were 000 new cases per year. In Canada and the United States, stomach cancer is rare. It is even in decline. In 2009, it accounted for less than 2% of all new cancer cases among Canadians.

In industrialized countries, refrigeration has helped reduce the incidence of stomach cancer.