Causes of Stomach Cancer

The causes of stomach cancer are not well understood. As with all cancers, the malignant tumor developes because damage occurs to a cell's DNA. If enough of these areas of damage, called mutations, occur, it can lead to cancer. The same process takes place in the cells in the wall of the stomach, particularly the lining cells, called the mucosa, giving rise to stomach cancer. However, the underlying things that lead to this damage is not well understood.

There are some factors which are thought to contribute, at least in part, to the development of stomach cancer. These risk factors are known to be associated with the disease. Each are not causes of stomach cancer per se, but they are factors that seem to increase an individual's chances of developing this form of cancer. The more risk factors an individual has, the greater their chance of developing stomach cancer.

• Helicobacter pylori: H. pylori is a bacteria which is a common colonizer of the stomach. It lives along the lining of the stomach and can contribute to gastritis (chronic inflammation of the stomach lining) and ulcers. Chronic infection with H. pylori also increases the risk of stomach cancer.
• Male Gender: Men are more likely to develop stomach cancer than women, more than 2 times as likely.
• Diet: There are two aspects of diet which appear to influence stomach cancer. One of the most important is that a diet which is high in cured, smoked or preserved foods, particularly those with high levels of nitrates/nitrites, increases the risk of stomach cancer. In the US, because of the widespread availability of refrigeration, the use of curing and preserving techniques has decreased with time and stomach cancer has decreased as well. However, in some countries, such as in Japan, these foods are still consummed commonly and the rate of stomach cancer is higher. Also, a diet low in fruits and vegetables appears to contribute to the causes of stomach cancer as well.
• Age: Advancing age is associated with a greater risk. The average age for the development of stomach cancer is at least 70.
• Gastritis: Gastritis is inflammation of the lining of the stomach. Chronic gastritis can be caused by H. pylori infection as well as by irritants such as smoking, frequent non-steroidal anti-inflammatory drugs (ibuprofen, motrin, tylenol, etc.), alcohol and others.
• Gastric Polyps: Polyps are small benign growths that can arise from the lining of the stomach. Like colon polyps, some types of polyps can lead to cancer if not removed first.
• Family History: Those with a close blood relative with a history of stomach cancer can have as much as double to triple the risk of developing it themselves.
• Smoking: As with many cancers, stomach has been connected to risk for stomach cancer.
• Others: There are other conditions or exposures which may have some impact on the causes of stomach cancer, such as alcohol, exposure to asbestos, history of pernicious anemia and work in certain industries (such as coal mining, rubber processing, nickel refining and others).