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Cancer,Stomach

Overview

Stomach cancer tends to affect those over the age of 55, and it is almost twice as common among men than women. 

The stomach 

The stomach is an organ that links the oesophagus (gullet) and the duodenum (top of the small intestine). It is part of the digestive system, and its main function is to digest food that is eaten so that the nutrients can be easily absorbed into the body. It does this by contracting the muscles in the stomach wall that help to break down solid food. 

Types of stomach cancer 

There are several different types of stomach cancer. The most common type is known as adenocarcinoma of the stomach, which develops in the stomach lining.

A less common type of stomach cancer is lymphoma of the stomach, which develops in the lymphatic tissue (tissue that drains away fluid and helps fight infection). Another less common type is sarcoma of the stomach, which develops in the muscle or connective tissue of the stomach wall.

Treatment for stomach cancer usually consists of combinations of surgery, chemotherapy and radiotherapy. Once it has developed, stomach cancer can spread to other parts of the body, including the pancreas, liver and gullet. So the earlier the condition is diagnosed, the better the chances are that it will be treated successfully.

Causes

Cancer is caused by the cells in a certain area of your body dividing and multiplying too rapidly. It is not fully understood why cancer of the stomach occurs, but research into the condition is continuing.

Although the cause of stomach cancer is not fully understood, there are several possible causes and risk factors that may make developing the condition more likely. The possible causes and risk factors are outlined below.

Age

Your risk of getting stomach cancer increases with age. Most cases of stomach cancer occur in people who are over the age of 55.

Smoking

Smokers may be twice as likely to develop stomach cancer compared with non-smokers. This is because some tobacco smoke will always be swallowed when you inhale and end up in your stomach.

As well as stomach cancer, smoking causes many other forms of cancer, and increases your risk of heart disease and stroke.

Helicobacter pylori infection

Infection with bacteria known as Helicobacter pylori (H pylori) may be linked to stomach cancer in the lower part of your stomach. H pylori infections are very common, although only a small number of people affected by H pylori develop stomach cancer as a result.

It is possible to be infected with H pylori without knowing it because it does not usually cause any symptoms. However, in some cases, an H pylori infection can cause conditions such as stomach ulcers, dyspepsia (recurring bouts of indigestion), or atrophic gastritis (chronic inflammation of the stomach lining).

As the majority of people with an H pylori infection do not go on to develop stomach cancer, it suggests that the condition has other contributory factors. It could be that an H pylori infection leads to stomach cancer when it is combined with other risk factors, such as smoking, or a high salt diet.

Family history

You are more likely to develop stomach cancer if you have a close relative with the condition, such as one of your parents, or your brother, or sister. It is not yet fully understood why this, but it is possible that it is due to family members sharing certain risk factors, such as the Helicobacter pylori infection.

Research into stomach cancer has also shown that you may be more at risk of getting the condition if you have the blood type A. Your blood type is passed on from your parents, so this could be another way in which family history may increase your risk of developing stomach cancer.

There is also a condition which runs in families, called familial adenomatous polyposis (FAP), which may make developing stomach cancer more likely. FAP causes small growths, called polyps, to form in your digestive system, and it is known to increase your risk of developing bowel cancer.

Having another type of cancer

If you have had another type of cancer, such as cancer of the oesophagus (gullet), or non-Hodgkin's lymphoma (cancer that develops in the white blood cells in your immune system), you have an increased risk of developing stomach cancer.

There are also other cancers that can make developing stomach cancer more likely, for both men and women. If you are a man, your risk of stomach cancer is increased if you have had cancer of the prostate, bladder, bowel or testicle. If you are a woman, your risk of developing stomach cancer increases if you have had cancer of the ovary, breast or cervix.

Certain medical conditions

Having certain medical conditions can also increase your risk of developing stomach cancer. These are outlined below.

  • Oesophagitis - inflammation of your gullet caused by a reflux of stomach acid.
  • Gastroesophageal reflux disease (GORD) - a severe form of oesophagitis.
  • Pernicious anaemia - a vitamin B12 deficiency which occurs when you body cannot absorb it properly.
  • Peptic stomach ulcers - an ulcer in your stomach lining, often caused by Helicobacter pylori infection.
  • Barrett's oesophagus - abnormal changes to the cells in the oesophagus (gullet). This condition also increases your risk of developing cancer of the oesophagus.


Surgery affecting the stomach

If you have had surgery to your stomach, or to a part of your body that affects your stomach, you may be more likely to develop stomach cancer.

This can include surgery to remove part of your stomach (known as a partial gastrectomy), or surgery to remove part of your vagus nerve (the nerve that carries information from your brain to organs such as your heart, lungs, and digestive system). Surgery such as this may reduce the amount of acid in your stomach, which can allow bacteria and other cancer causing chemicals to grow.

An operation to remove a peptic stomach ulcer may also increase your risk of developing stomach cancer, for as long as 20 years after the surgery. This may be caused by a reflux of the digestive juices from your intestines, which can inflame the lining of your stomach.

Diagnosis

You should see your GP as soon as possible if you are experiencing symptoms similar to those of stomach cancer (see the 'symptoms' section). Your GP will ask about your symptoms, and examine your stomach for any lumpiness or tenderness.

 

Preliminary tests

 

If your GP thinks that you may have stomach cancer, they will refer you to a specialist for tests. These will include a blood test and chest X-ray to assess your overall health. A sample of your stools may also be tested for blood.

If you are diagnosed with stomach cancer, the tests may also help to identify the stage and grade of your condition, which your oncologist (specialist in cancer) will discuss with you thoroughly.

The stage is used to describe the spread of the cancer at the time of diagnosis, and the grade indicates how aggressively it is spreading. However, it may not always be possible to identify the exact stage of your condition until your treatment starts and you have surgery.

Stages and grades help your doctors to decide on the best kind of treatment for your condition. However, it is important to remember that the stage and grade of your stomach cancer alone cannot predict how your condition will progress.

The various tests that you may have to diagnose stomach cancer, and those that can show the stage and grade of your condition, are outlined below.

 

Cancer markers test

 

The cancer markers test is an additional blood test to check for chemicals in your bloodstream, known as cancer markers. These markers are sometimes present in some types of cancer, although it is still possible to have cancer and not have cancer markers in your blood.

If you have stomach cancer, your blood may contain a cancer marker called carcinoembryonic antigen (CEA). However, only approximately half of all people with stomach cancer will have a high level of CEA in their blood.

 

Endoscopy or endoscopic ultrasound

 

An endoscopy is a procedure where a healthcare professional examines the inside of your stomach using a device known as an endoscope, which is a thin, long flexible tube with a light and a video camera at the end.

If you need to have an endoscopy, you will not be able to have anything to eat or drink for between 4-8 hours before the procedure. This is to ensure that your stomach and duodenum (top of the small intestine) are empty.

You will be awake for the endoscopy, but you may be given a sedative by injection to make you feel drowsy and relaxed. You may also have a local anaesthetic sprayed onto the back of your throat, so that the area is numbed.

The endoscope will then be passed down your throat and into your stomach so that the specialist can look for any stomach ulcers, or signs of cancer. If any tissue is found that may be cancerous, your specialist will take a sample of it for testing. This procedure is known as a biopsy.

If your specialist thinks that you may have cancer in the top part of your stomach, you may have an ultrasound scan at the same time as an endoscopy, which is known as an endoscopic ultrasound. An ultrasound scan uses high frequency sound waves to produce an image of your stomach, and this method is used to view an unborn baby in the womb.

If you have an endoscopic ultrasound, an ultrasound probe will be attached to the end of the endoscope before it is passed down your throat. The scan will help to show the stage of any cancer in the top part of your stomach.

After an endoscopy, or an endoscopic ultrasound, you will not be able to drive for several hours due to the sedative. You may have a sore throat after the procedure, although this should pass within a few days.

 

Barium meal X-ray

 

A barium meal X-ray uses a liquid containing a substance called barium, which makes your stomach show up on an X-ray. Normally, organs such as your stomach do not show up on an X-ray because they are made of soft tissue that is not dense enough to stop the X-rays passing through. However, when these organs are filled with barium, it blocks the X-rays and shows up white on an X-ray screen.

If you need to have a barium meal X-ray, you will not be able to eat or drink anything for at least six hours before the procedure so that your stomach and duodenum (top of the small intestine) are empty. You may be given an injection to relax the muscles in your digestive system.

You will then lie down on a couch and your specialist will give you a white, chalky liquid to drink which contains barium. As the barium fills your stomach, your specialist will be able to see your stomach on an X-ray monitor, as well as any ulcers, or abnormal growths. Your couch may be tipped slightly during the test so that the barium fills all the areas of your stomach.

You may feel slightly sick after a barium meal X-ray, and the barium may cause constipation. Your stools may also be white for a few days afterwards as the barium passes through your system.

 

Laparoscopy

 

If your specialist needs to examine your stomach in more detail, in order to look for the signs of the spread of cancer, you may have a small operation called a laparoscopy. This procedure is carried out under a general anaesthetic, which means that you will be asleep.

Your specialist will insert a thin viewing tube with a camera on the end (a laparoscope) through a small cut (incision) in the lower part of your stomach in order to examine it. In some cases, your specialist may need to examine more than one area of your stomach, and may need to make more than one incision.

 

CT or MRI scan

 

If your specialist thinks that you have stomach cancer which may have spread, you may have a computerised tomography (CT) scan, a magnetic resonance (MRI) scan, or both. These scans are used to produce detailed pictures of the inside of your body, and can show the location of cancer spread anywhere within your body.

A CT scan uses a series of X-rays to form an image, and an MRI scan uses a strong magnetic field and radio waves to produce a detailed image of the inside of your body.

 

Liver ultrasound scan

 

If your specialist thinks that your stomach cancer may have spread to your liver, you may need to have a liver ultrasound. This type of scan uses high frequency sound waves to produce an image of your liver.

Treatment

Treatment for cancer of the stomach is usually carried out through a combination of surgery, chemotherapy and, in some cases, radiotherapy. The amount of each treatment that you receive will depend on the type of stomach cancer that you have, as well as its stage and grade and your overall health.

You will receive treatment from a team of healthcare professionals headed by an oncologist (a specialist in cancer). Do not be afraid to discuss any fears and concerns that you have with your oncologist; they will be able to explain each phase of your treatment.

Surgery

Most cases of stomach cancer require surgery, which often involves a large operation.

It is very likely that you will have surgery if your cancer has not spread beyond your stomach. The aim of the surgery will be either to remove all of the cancer, or as much of it as possible.

However, if your cancer has spread beyond your stomach, it may not be possible to remove it completely through surgery. If this is the case, you may still have surgery to remove any cancer that is blocking your stomach, in order to ease your symptoms.

Surgery to remove stomach cancer

If you have surgery to remove the cancer in your stomach, and depending on where in your stomach the cancer is, it is likely that you will need to have part, or all, of your stomach removed.

Surgery to remove part of your stomach is known as a partial gastrectomy, and surgery to remove all of your stomach is known as a total gastrectomy. In some cases, your surgeon may also remove part of your oesophagus (gullet), as well as the whole of your stomach, which is known as an oesophagogastrectomy.

Partial gastrectomy

If your cancer is in the lower part of your stomach, you may have a partial gastrectomy, in which only part of your stomach is removed. This means that the lower part of your stomach will be removed and, afterwards, your stomach will be smaller than it was before surgery. However, the operation will not affect the top part of your stomach, where your oesophagus (gullet) feeds into it.

If you have a partial gastrectomy, you will only be able to eat small amounts of food for a while after your operation. This is because your stomach will not be able to hold as much food as it could before the surgery, and your body will need to adjust to its new stomach capacity. Your cancer team can offer advice about what and when you should eat. You should gradually be able to increase the amount that you eat as your stomach begins to expand.

Total gastrectomy or oesophagogastrectomy

If your cancer is in the middle, or at the top, of your stomach, you may need to have a total gastrectomy, where the whole of your stomach is removed. If the cancer is close to the end of your oesophagus (gullet), where it meets your stomach, you may also need to have part of your gullet removed. This kind of surgery is known as an oesophagogastrectomy.

If you have a total gastrectomy, your stomach will be removed and the end of your gullet will be joined to the top of your duodenum (the top part of your small intestine). If you have an oesophagogastrectomy, your stomach and the end of your gullet will be removed, and the remaining part of your gullet will be joined to your duodenum.

During both of these operations, your surgeon will also remove the lymph nodes (tissues that remove bacteria from your body) nearest to the cancer in your stomach. It is possible that your stomach cancer may have spread to these lymph nodes, so removing them helps to prevent the cancer from recurring.

If you have surgery to remove all of your stomach, it may be quite some time before you can eat normally again. As with a partial gastrectomy, you will only be able to eat small amounts of food until your body adjusts. You may have to eat little and often, and make changes to the types of food that you eat. Your cancer team will be able to advise you about what and when you should eat.

Having surgery to remove your stomach also means that you will need to have regular injections of vitamin B12. This vitamin is normally absorbed through your stomach from the food that you eat, and is needed to help prevent anaemia (fatigue and weakness caused by a lack of red blood cells) and nerve problems.

Surgery to ease your symptoms

If your stomach cancer has spread beyond your stomach, it may not be possible to remove it through surgery.

However, if you have a large amount of cancer in your stomach, it can cause a blockage which prevents food from being properly digested. A blocked stomach can cause symptoms such as stomach pain, vomiting, and feeling very full after eating.

If you have a blocked stomach, you may be able to have a partial, or total, gastrectomy in order to reduce the blockage and improve your symptoms. See 'surgery to remove stomach cancer' (above) for more information about these operations.

Alternatively, if gastrectomy surgery is not suitable for you, your surgeon may suggest bypass surgery to ease your symptoms. In a bypass operation, the part of your stomach above the blockage is joined to your duodenum (the top part of your small intestine), leaving the blocked part of your stomach out of your digestive system. This allows food to move through the unblocked part of your stomach and into your intestines, without coming into contact with the blockage.

After surgery for stomach cancer

Any kind of surgery for stomach cancer will involve a large operation and a long recovery time. If you have stomach cancer surgery, you will usually have to stay in hospital for approximately two weeks.

You will also need several weeks to recover at home, which can be a difficult time.

Chemotherapy

Chemotherapy is a specialist treatment for cancer which uses medicines that can stop the growth of cancer cells. These medicines are known as cytotoxic, which means that they target rapidly growing cancer cells, stopping them from dividing and multiplying. As it circulates through your system, the medicine can target cancer cells in your stomach, as well as any that may have spread elsewhere in your body.

You may have chemotherapy for stomach cancer before surgery in order to reduce the amount of cancer that your operation has to remove. You may also have chemotherapy after surgery to destroy any remaining cancer cells, and prevent the cancer from recurring. Chemotherapy can also be used to slow the progression of cancer, and ease the symptoms of more advanced stomach cancer, which may not be suitable for surgery.

If you need to have chemotherapy, the medicine may be given as tablets, or intravenously (by injection, or a drip through a vein directly into your bloodstream). Chemotherapy is usually given in hospital, with several weeks between treatment sessions to give your body a rest between treatments.

Alternatively, the medicine may be fed into your system through a small pump, which gives you a constant low dose of chemotherapy over a period of a few weeks, or months. The pumps are portable and can be worn at home, which can mean fewer trips to hospital.

Side effects of chemotherapy

Chemotherapy works by preventing cells, such as those that are cancerous, from growing rapidly. However, there are other cells that occur naturally in your body which also divide and multiply rapidly, including hair follicles, and red and white blood cells. As a result, chemotherapy destroy these non-cancerous cells, which can cause many different side effects including:

  • hair loss,
  • nausea and vomiting,
  • diarrhoea, or constipation,
  • rashes on the skin of your hands and feet,
  • loss of appetite,
  • sores around your mouth,
  • anaemia (tiredness and breathlessness brought on by a lack of red blood cells), and
  • leukopenia (infection brought on by a lack of white blood cells).

If you need to have chemotherapy, the side effects that you experience will depend on the type of cytotoxic medicine that you take, the number of treatment sessions that you need to have, and your individual reaction to the treatment.

If you experience nausea and vomiting as a result of chemotherapy, you may be able to take anti-sickness medication to counter it. This may be given intravenously (by injection directly into your bloodstream) at the same time as your chemotherapy.

The side effects of chemotherapy will only last for as long as your course of treatment lasts. Once your treatment is over, the rapidly growing cells that occur naturally in your body will repair themselves. This means that your hair will grow back, although it might look or feel different to how it did before your chemotherapy. For example, it may be a slightly different colour, or be softer or curlier than before.

Radiotherapy

Radiotherapy uses high energy X-rays and, like chemotherapy, works by targeting rapidly growing cancer cells. Radiotherapy is not often used to treat stomach cancer because there is a risk that other organs that are very close to your stomach might be damaged by the treatment.

However, you may need to have radiotherapy for stomach cancer if you have an advanced form of the condition that is causing bleeding, or pain.

In some cases, following surgery, you may have chemotherapy and radiotherapy together, in order to help to prevent the stomach cancer from recurring. However, this type of treatment is still being researched and, if it is offered to you, it is likely to be as part of a clinical trial.

If you need to have radiotherapy, your treatment will begin about a month after your surgery, or chemotherapy, in order to give your body a chance to recover. It is a painless procedure in which you lie under a radiotherapy machine while it directs radiation at your stomach. You will be positioned by your radiographer (a specialist in radiotherapy) so that the machine targets only the cancer cells and avoids as much of your healthy tissue as possible.

It is likely that you will have radiotherapy sessions five days a week, for between 3-6 weeks. Each session will only last a few minutes. The radiation does not stay in your system afterwards, and it is perfectly safe to be around others in between your treatments.

Side effects of radiotherapy

As radiotherapy works by targeting rapidly growing cancer cells, like chemotherapy, it can have several side effects. Other rapidly growing cells that occur naturally in your body are also damaged by radiotherapy, including the skin cells, and the cells that line your digestive system. The side effects of radiotherapy may include:

  • nausea with, or without, vomiting,
  • diarrhoea,
  • tiredness,
  • stomach pain, and
  • irritation and darkening of your skin where the treatment takes place.

However, as radiotherapy is usually only used to treat advanced stomach cancer, you may not experience side effects. The aim of the treatment is to relieve your symptoms and make you feel better, so any side effects should be kept under control. You may be given medicines for this, such as anti-sickness medication

Prevention

As the causes of stomach cancer are not fully understood, it is not known if there is anything which can prevent it altogether. However, a few factors have been identified which may make the chances of developing stomach cancer less likely.

 

Eating a healthy diet

 

Research into stomach cancer has found that the condition is far more common in countries where pickled foods are often eaten, such as Japan. This is due to the fact that pickled foods are usually very high in salt, which is thought to increase your risk of developing stomach cancer.

Therefore, eating a diet which is low in salt and processed foods, and high in fruit and vegetables, may help to reduce the risk of stomach cancer. Fruit and vegetables contain antioxidants, which may help to protect your stomach lining from damage which can lead to cancer.

The Food Standards Agency recommends that adults should consume no more than 6g of salt a day, and that you should eat at least five portions of fruit and vegetables a day. As well as helping to prevent stomach cancer, following these recommendations will help to protect against other forms of cancer and heart disease, as well as improving your overall health.

 

Quitting smoking

 

If you smoke, your risk of developing stomach cancer may be twice that of someone who is a non-smoker. This is due to the fact that some tobacco smoke will always be swallowed when you inhale and end up in your stomach.

As well as stomach cancer, smoking causes many other forms of cancer, as well as increasing your risk of heart disease and stroke.

Symptoms

There are several symptoms of cancer of the stomach. However, as the symptoms are similar to those of many other, less serious conditions, stomach cancer can sometimes be difficult to recognise. For this reason, stomach cancer can often be quite advanced by the time that it is diagnosed.

It is therefore important to get any possible symptoms of stomach cancer checked out as soon as possible. Although it does not necessarily mean that you have stomach cancer, you should see your GP if you experience any of the symptoms outlined below.

Early symptoms of stomach cancer may include:

  • persistent indigestion,
  • trapped wind and frequent burping,
  • heartburn,
  • feeling full very quickly when eating,
  • feeling bloated after eating,
  • pain in your stomach or breastbone (sternum),
  • difficulty swallowing,
  • nausea, and
  • vomiting (which may be streaked with bright red, or dark coloured, blood).

The symptoms of more advanced stomach cancer may include:

  • blood in your stools, or black stools,
  • loss of appetite,
  • weight loss,
  • tiredness,
  • lumpiness in your stomach (caused by a build up of fluid), and
  • anaemia (lack of red blood cells caused by bleeding from the wall of your stomach