Stomach (Gastric) Cancer

gastric cancer

Although stomach cancer is common worldwide. Most cases occur in people over the age of 55. If stomach cancer is diagnosed at an early stage, there is a good chance of a cure. In general, the more advanced the cancer (the more it has grown and spread), the less chance that treatment will be curative. However, treatment can often slow the progress of the cancer.

What is the stomach?

The stomach is in the upper abdomen. It is part of the gastrointestinal tract (the gut). It lies in the upper part of the abdomen, just below the ribs. When we eat, food passes down the oesophagus (gullet) into the stomach.

The stomach makes acid and some enzymes (chemicals) which help to digest food. The muscles in the wall of the stomach contract to mix up the food with the acid and enzymes.
Food then passes into the duodenum (the first part of the small intestine). Here food mixes with more enzymes which come from the pancreas and lining of the gut. The enzymes digest (break down) the food.

Digested food is then absorbed into the body from the small intestine.

What is cancer?

Cancer is a disease of the cells in the body where the abnormal cells multiply out of control. A malignant tumour is a lump or growth of tissue made up from cancer cells, which continue to multiply. Malignant tumours invade into nearby tissues and organs, which can cause damage. Also by invading blood vessels these cancerous cells can be deposited to other parts of the body, leading to secondary tumors (metastasis) in different areas of the body. Some cancers are more serious than others; some are more easily treated than others; some have a better outlook (prognosis) than others. Therefore, one has to know exactly what type of cancer one is treating before recommending any treatment.

What is stomach cancer?

Stomach cancer is sometimes called gastric cancer. Worldwide it is one of the most common cancers. Stomach cancer is more common in men than in women and tends to occur mainly in older people. Most people who develop stomach cancer are over the age of 55.

Adenocarcinoma of the stomach

In most cases, stomach cancer begins from a cell which is on the inside lining of the stomach (the mucosa). This type of stomach cancer is called adenocarcinoma of the stomach. As the cancer cells multiply:

The tumour may invade deeper into the wall of the stomach. In time, it may pass through the wall of the stomach and invade nearby organs such as the pancreas or liver.
The tumour may spread up or down the stomach into the oesophagus (gullet) or small intestine.

Some cells may break off into the lymph channels or bloodstream. The cancer may then spread to nearby lymph nodes or spread to other areas of the body (metastasise).
Other types of stomach cancer.

There are some less common and rare types of stomach cancer which include:

  • Lymphomas. These are cancers which arise from the lymphatic tissue within the wall of the stomach.
  • Sarcomas. These are cancers which arise from the muscle or connective tissue within the wall of the stomach.
  • Carcinoid cancers. These are cancers which arise from cells in the stomach lining which make hormones.

What causes stomach cancer (adenocarcinoma of the stomach)?

A cancerous tumour starts from one abnormal cell. The exact reason why a cell becomes cancerous is unclear. It is thought that something damages or alters certain genes in the cell. This makes the cell abnormal and multiply out of control. Many people develop stomach cancer for no apparent reason. However, certain risk factors increase the chance that stomach cancer may develop. These include:

  • Ageing. Stomach cancer is more common in older people. Most cases are in people over the age of 55.
  • Having a type of anaemia called pernicious anaemia, which causes a lack of vitamin B12, can very slightly increase your risk of stomach cancer.
  • Diet is probably a factor:
  • Countries such as Japan, where people eat a lot of salt, pickled and smoked foods, have a high rate of stomach cancer.
  • Eating a lot of fruit and green vegetables can reduce the risk.
  • Smokers have a higher rate of stomach cancer compared with people who do not smoke.
  • Long-term infection of the stomach lining with a bacterium called Helicobacter pylori seems to lead to a slightly higher risk of stomach cancer.
  • Gender. Stomach cancer is twice as common in men as in women.
  • If you have had part of your stomach removed in the past for any reason. For example, to treat a stomach ulcer or some other condition.
  • Family history. For some cases, stomach cancer may run in the family. However, most cases of stomach cancer do not run in families and are not inherited.
  • Blood group A. People who have this blood group have a slightly higher risk.

What are the symptoms of stomach cancer?

When a stomach cancer first develops and is small, it usually causes no symptoms. Some do not cause symptoms until they are quite advanced. Initial symptoms may include:

  • Pain or discomfort in the upper abdomen, especially after eating.
  • Indigestion. (Note: most people who have indigestion do not have stomach cancer.)
  • Feeling sick, off food. Some people have a sense of fullness after eating.
  • Weight loss and/or loss of appetite.
  • You may pass blood out with your faeces (motions). You may not notice bleeding if small amounts of blood pass out with your faeces. A lot of bleeding from the stomach can turn your faeces black.
  • As the cancer grows in the stomach, symptoms may become worse and may include:
    • The same symptoms as above, but more severe.
    • Feeling generally unwell and more tired than usual.
    • Becoming anaemic if the tumour regularly bleeds. This can cause you to become more tired than usual.
    • The cancer growing very large and causing a blockage to food and drink.
    • If the cancer spreads to other parts of the body, various other symptoms can develop.

Note: all the above symptoms can be due to other conditions, so tests are needed to confirm stomach cancer.

How is stomach cancer diagnosed and assessed?

Initial assessment and gastroscopy

If a doctor suspects that you may have stomach cancer, he or she may examine you. The examination is often normal, especially if the cancer is at an early stage. Therefore, a gastroscopy (endoscopy) is usually arranged.

A gastroscope (endoscope) is a thin, flexible, telescope. It is passed through the mouth, into the oesophagus and down towards the stomach and duodenum. The endoscope contains fibre-optic channels which allow light to shine down so the doctor or nurse can see inside your stomach and duodenum. See separate leaflet called 'Gastroscopy' for more details.

Biopsy - to confirm the diagnosis

A biopsy is when a small sample of tissue is removed from a part of the body. The sample is then examined under the microscope to look for abnormal cells. When you have a gastroscopy, if anything abnormal is seen then the doctor or nurse can take a biopsy. This is done by passing a thin grabbing instrument down a side channel of the gastroscope. It can take two weeks for the biopsy results.

Assessing the extent and spread

If you are confirmed to have stomach cancer, further tests may be done to assess if it has spread. For example, a barium meal X-ray, a CT scan, an MRI scan, an ultrasound scan, laparoscopy or other tests. This assessment is called staging of the cancer.

The aim of staging is to find out:

  • How much the tumour in the stomach has grown, and whether it has grown partially or fully through the wall of the stomach.
  • Whether the cancer has spread to local lymph nodes.
  • Whether the cancer has spread to other areas of the body (metastasised).
  • By finding out the stage of the cancer it helps doctors to advise on the best treatment options. It also gives a reasonable indication of outlook (prognosis).

What are the treatment options for stomach cancer?

Treatment options which may be considered include surgery, chemotherapy (and sometimes radiotherapy). The treatment advised for each case depends on various factors such as the stage of the cancer (how large the cancer is and whether it has spread), and your general health.

It is important to make sure you get enough nutrition from your food and you will probably be asked to see a dietician to make sure you are on the best possible diet.


Removing the tumour may be curative if the cancer is in an early stage. The common operation is to cut out the affected part of the stomach. Sometimes the whole of the stomach is removed. Sometimes this is done laparoscopically (key-hole surgery). Even if the cancer is advanced and a cure is not possible, some surgical techniques may still have a place to ease symptoms. For example, a blockage may be eased by removing part of the stomach, or by using laser surgery or by a bypass operation.


Chemotherapy is a treatment of cancer by using anti-cancer medicines which kill cancer cells or stop them from multiplying. When chemotherapy is used in addition to surgery it is known as adjuvant chemotherapy. For example, following surgery you may be given a course of chemotherapy. This aims to kill any cancer cells which may have spread away from the primary tumour. Sometimes, adjuvant chemotherapy is given before surgery to shrink a large tumour so that surgery is easier.


Radiotherapy is a treatment which uses high energy beams of radiation which are focussed on cancerous tissue. This kills cancer cells, or stops cancer cells from multiplying. Radiotherapy is not commonly used to treat stomach cancer. It is sometimes used to reduce the size of a particular part of the cancer which is causing symptoms.


In some cases a combination of chemotherapy and radiotherapy - shortened to chemoradiotherapy - is offered, often as an addition to surgery. If you need to have this, it is usually done around the time of the operation.

What is the prognosis (outlook)?

Without treatment, a stomach cancer is likely to get larger, and spread to other parts of the body. If it is diagnosed and treated at an early stage (before growing through the wall of the stomach or spreading to lymph nodes or other areas of the body) then there is a good chance of a cure with surgery.

If the cancer is diagnosed when it has grown through the wall of the stomach, or spread to other parts of the body, a cure is less likely. However, treatment can often slow down the progression of the cancer using chemotherapy medicines.

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