In the UK, stomach, or gastric, cancer is the seventh most common cancer.
About 8,000 people are diagnosed with stomach cancer each year. It's about twice as common in men as it is in women. More than nine in 10 people diagnosed with stomach cancer are over the age of 55.
About stomach cancer
The stomach is a muscular bag in your abdomen (tummy) that digests the food you eat. The stomach lining produces a strong acid to help digest the food and protect you from harmful bacteria. The food is also broken down by the churning action of the stomach. The food then passes into the duodenum, the first part of the small intestine.
Most stomach cancers form a tumour (lump) or ulcer in the inner lining of the stomach. Less commonly, the cancer spreads along the stomach wall without forming a discrete lump. This is known as a diffuse tumour.
In the early stages, stomach cancer is contained within the stomach lining or stomach wall. However, the cancer cells can also spread into neighbouring organs. This is called localised spread. Sometimes the cancer cells can break away and travel to distant parts of the body in the blood stream and lymph system (the lymphatic system which makes up part of your body's immune system). This is called metastasis.
Types of stomach cancer
There are several types of stomach cancer.
- About 95 percent of stomach cancers are adenocarcinomas. These start in the glandular cells which make up part of the stomach lining.
- Squamous cell carcinomas develop from the squamous cells, which also make up part of the stomach lining.
- Soft tissue sarcomas start in the muscle layer of the stomach wall.
- Lymphomas develop in the lymphatic system.
- Carcinoid tumours are tumours of the neuroendocrine system - the system of glands throughout your body - and can also affect the stomach.
Early stomach cancer can cause very mild indigestion-like symptoms. These include:
- feeling full after eating only a small meal
- stomach pain
- difficulty swallowing
As the cancer grows, you may have other symptoms such as weight loss, vomiting blood, or passing blood in faeces. This isn't usually fresh, red blood, but dark blood. The blood loss may go unnoticed, but over a period of time, it can cause anaemia (when you have too few red blood cells or not enough haemoglobin in your blood).
When to seek medical advice
Many people have the symptoms indigestion. But most of these people don't have stomach cancer. According to Cancer Research UK, only one in a million people who get indigestion under the age of 55 have stomach cancer. But you should visit your GP if you get the following symptoms:
- vomiting for more than a few days - if it contains blood you should visit your doctor straight away
- unexplained or sudden weight loss
- difficulty swallowing
- persistent abdominal pain
- "swelling in the stomach area
- developing indigestion and you are over 45
No one knows why some people develop stomach cancer and others don't. The number of people affected varies widely between different countries. For example, stomach cancer is far more common in Japan than in the UK. There is also evidence that people from poorer backgrounds are at increased risk.
There are a many other factors that increase the risk of developing stomach cancer.
- Age. Stomach cancer is most common around the age of 60. It's rare under the age of 40.
- Gender. Men are around twice as likely to develop stomach cancer as women.
- Helicobacter pylori infection. These bacteria live in the stomach lining of many people, and don't usually cause any symptoms. However, the infection sometimes causes inflammation of the stomach lining (gastritis), indigestion and stomach ulcers. It is known to increase the risk of stomach cancer.
- Diet. A diet high in salt and foods that are smoked or cured may increase the risk of stomach cancer. In particular, certain food preservative chemicals known as nitrosamines, which are found cured meats such as bacon and ham, may increase your chance of developing stomach cancer.
- Family history. Some people inherit an increased risk of developing stomach cancer.
- Type A blood group. Some research indicates that people who have type A blood are at higher risk of developing stomach cancer.
- Smoking. When you smoke, you swallow small amounts of tobacco smoke, which increases your risk of getting stomach cancer.
- Atrophic gastritis. This condition causes the lining of the stomach to waste away. It has also been linked with an increased risk of stomach cancer.
- Pernicious anaemia. This is type of anaemia raises your risk of stomach cancer.
Your GP will ask about your symptoms and examine you. If he or she suspects a stomach ulcer or cancer you will need some more tests. Some of these tests are described below.
- Blood test. This test is done to check for anaemia and to assess liver function.
- Barium meal. This test involves swallowing a drink containing barium, which makes the stomach show up clearly on an X-ray image. Problems such as ulcers or tumours can then be seen.
- Gastroscopy. In this test you swallow a camera attached to a flexible tube. It passes down into your stomach. Your doctor can then inspect the stomach lining on a video screen. The same instrument can also take a sample (biopsy) from any areas that look suspicious. These are sent for examination in a laboratory.
- Scanning. If cancer is suspected, computerised tomography (CT), magnetic resonance imaging (MRI) or ultrasound scans of the stomach, liver, and surrounding lymphatic system can be used to see if the cancer has spread.
If you are diagnosed with stomach canver your GP will refer you to an oncologist (doctor who specialises in treating cancer).
If stomach cancer is diagnosed early, it can be treated with surgery. If it hasn't spread outside the stomach, then either the whole stomach (gastrectomy) or just the affected part of it may be removed. If the cancer has spread, surgery won't cure the cancer but it can help relieve symptoms.
Chemotherapy uses medicines to destroy cancer cells. There are lots of different types of chemotherapy drugs. They are usually injected into a vein, but sometimes you can take them as tablets.
Chemotherapy drugs have a variety of side effects. These include making you feel tired or ill, or causing nausea or hair-loss. Your specialist will advise you about what side effects to expect.
Chemotherapy can be used after surgery, and sometimes before, to try and reduce the chances of stomach cancer coming back. It's often used to control the growth of the cancer and help relieve symptoms.
Radiotherapy uses radiation to destroy cancer cells. A beam of radition is targeted on cancer cells. It isn't usually used to treat stomach cancer, but it's sometimes used in combination with chemotherapy. Talk to your doctor for more information about your treatment options.
Eating a diet rich in fruit and vegetables and not smoking will reduce your risk of developing stomach problems, including cancer. Try to be aware of the symptoms of stomach cancer, and talk to your GP promptly if you think you are affected.
Cancer Research UK
Digestive Disorders Foundation
- Cancer Research UK. www.canceresearchuk.org, accessed 2 May 2007
- Types of stomach cancer. Cancerbackup. www.cancerbackup.org.uk, accessed 2 May 2007
- Simon C, Everitt H, and Kendrick T. Oxford handbook of general practice. 2nd ed: Oxford University Press, 2005
- Bowles MJ and Benjamin IS, Cancer of the stomach and pancreas. BMJ 2001; 323: 1413-1416. www.bmj.com
- Paik DC, Saborio DV, Oropeza R, et al. The epidemiological enigma of gastric cancer rates in the US: was grandmother's sausage the cause? International Journal of Epidemiology, 2000. 30: 181-182