Stomach Cancer explained

What is the stomach for?

The stomach is a storage organ for food. When you eat your meals, food stays in the stomach for a while, and this is where digestion starts. Food is churned up, and mixed with acid until it is partly liquefied, when it is passed on into the rest of the bowel for further digestion, and for the nutrients to be absorbed. The stomach is actually a large hollow muscle, whose movement is controlled by nerves and hormones, triggered by the sight, smell or sound of food.

How common is stomach cancer?

The incidence of stomach cancer has decreased rapidly over the last fifty years, probably due to improved diet and living conditions. About 10,000 new cases per year are diagnosed in England and Wales. It is more common in some parts of the world such as Japan, China, Eastern Europe and Central and South America. In the UK lung, breast and colon cancer are seen much more frequently. Stomach cancer is much more common in older people, but sometimes affects patients in their 30s or 40s.

Your body

How does stomach cancer start?

Cancers of the stomach are not all the same, and it is likely that there are different causes.

Certain conditions of the stomach may predispose to stomach cancer. These include pernicious anaemia, chronic inflammation, ulcers and large polyps. Smoking, and a high salt or high nitrate/nitrite diet may also cause problems. Nitrites are found in cured meats, pickled fish, and may also originate in fertilisers.

Helicobacter pylori is a bacterium which can infect the stomach. This may lead to ulcers, and is also thought to predispose to stomach cancer.

Stomach cancer does not often run in families; a family history of stomach cancer is found in less than one in ten patients with the condition.

How does an ulcer turn into a cancer?

The genes that control the growth of stomach cells become disorganised, making the cells grow quickly, and beyond their normal boundaries. As the tumour enlarges, the cells grow through the lining of the stomach, and can invade adjacent structures such as fat or the pancreas. Some cells can break away, travel up the bloodstream and go to other sites such as the liver or lungs. These are known as secondaries, or metastases.

What protects against stomach cancer?

A healthy diet containing fruit, vegetables and some animal fat and protein may help to prevent stomach cancer. The widespread use of frozen rather than pickled foods may have influenced the reduction in the incidence of the problem over the last fifty years.