Stomach cancer is cancer that begins in the stomach. Men are affected more than women.

What is going on in the body?

Stomach cancer usually arises from cells that line the inside of the stomach. A cell will undergo changes that cause it to become cancerous. It will begin to grow and multiply uncontrollably. The cancer cells will form a tumor. The tumor will invade and destroy tissues around it as it grows. Eventually it can penetrate through the wall of the stomach and spread to structures around the stomach. Cancer cells can also break off from the tumor and enter the blood stream. These cells will form new tumors in other parts of the body, a process known as metastasis.

What are the causes and risks of the disease?

No one knows the precise reason why this cancer occurs. People from Japan are at higher risk than people from other areas. Risk decreases when people at risk move to areas of lower risk. This may be due to changes in diet, but this has not been proven. Cancer of the stomach is higher among people who smoke and consume alcohol than in those who do not.

Risk factors for stomach cancer include: