Definition Stomach cancer is cancer that begins in the stomach. Men are affected more than women.
What is going on in the body? Stomach cancer usually arises from cells that line the inside of the stomach. A cell will undergo changes that cause it to become cancerous. It will begin to grow and multiply uncontrollably. The cancer cells will form a tumour. The tumor will invade and destroy tissues around it as it grows. Eventually it can penetrate through the wall of the stomach and spread to structures around the stomach. Cancer cells can also break off from the tumour and enter the blood stream. These cells will form new tumours in other parts of the body, a process known as metastasis.
What are the signs and symptoms of the disease? Because the symptoms are vague and often ignored, stomach cancer can grow in the stomach for a long time before it is detected. The most common symptom is unexplained weight loss. People may complain of an uneasy sense of fullness, stomach heaviness, or distension. A person may also have chronic nausea and pain in the middle of the abdomen. These symptoms indicate advanced disease. Most stomach cancers are found in the advanced stage.
What are the causes and risks of the disease? No one knows the precise reason why this cancer occurs. People from Japan are at higher risk than people from other areas. Risk decreases when people at risk move to areas of lower risk. This may be due to changes in diet, but this has not been proven. Cancer of the stomach is higher among people who smoke and consume alcohol than in those who do not.
Risk factors for stomach cancer include:
family history
type A blood
lack of stomach acid
low socio-economic status
low consumption of fruits and vegetables
consumption of salted, smoked, or poorly preserved food
What can be done to prevent the disease? Avoiding all tobacco products will decrease the likelihood of developing stomach cancer. Although not proven, a diet that has fruits and vegetables as a component may also be helpful in avoiding this cancer. Some conditions are thought to lead to stomach cancer. They include:
chronic gastritis, which is inflammation of the stomach
previous stomach surgery, such as a partial gastrectomy
H. pylori infection, a bacterial infection of the stomach
certain gastric polyps, such as those that are adenomatous
pernicious anaemia, a low red blood cell count thought to be caused by an autoimmune disorder
Menetrier's disease, a form of gastritis in which the stomach lining has excess folds
How is the disease diagnosed? Usually, a person sees a doctor because of a symptom such as weight loss and nausea. The doctor will take an in-depth history, which includes a nutritional assessment. The first test may be an x-ray of the stomach called an upper gastrointestinal examination, or upper GI. Depending on the results of the upper GI, the next part of the evaluation will be a flexible gastroscopy in which a tiny tube with a light is passed into the stomach. This allows the physician to look at the walls of the stomach. If any of the tissue looks unusual, a biopsy will be done to remove a piece to determine if it is cancer.
If cancer is confirmed, other tests will be done to determine the extent of the disease. These tests include CT scans and other specialised x-rays. Tumour markers, or chemical markers produced by tumours, are not useful in diagnosing early stage stomach cancer but may be useful to track the cancer after surgery.
What are the long-term effects of the disease? This cancer is usually found late in the course of the disease when treatment is not likely to be effective.
What are the risks to others? There are no risks to others.
What are the treatments for the disease? If the disease is found early, surgery to remove all of the cancer and some surrounding tissue can be performed. Sometimes chemotherapy or radiation therapy is given before surgery to shrink the tumour. Chemotherapy and radiation are sometimes offered after surgery to help prevent recurrence. Surgery to bypass advanced cancer can relieve symptoms of nausea. Chemotherapy or radiation therapy may also shrink uncomfortable tumours in people with advanced cancers. Advanced stomach cancer is not curable.
What are the side effects of the treatments? Removing most of the affected stomach may mean the person will have to permanently modify the diet. Many patients will experience dumping syndrome, which is sweating and weakness after eating. Small, frequent meals are recommended. Side effects of chemotherapy are significant but manageable. The specific side effects vary according the medication given. Radiation therapy to the area can cause diarrhoea and increased nausea. This is generally manageable and will resolve when treatment ends.
What happens after treatment for the disease? The person will be monitored to determine the response of the cancer to treatment. If the cancer was completely removed, the person will be monitored over time to determine if the cancer returns. If the cancer returns or progresses, different therapy can try to improve quality of life. Treatment at this point will not cure the cancer.
How is the disease monitored? CT scans are used to monitor the spread of the disease to other organs such as the liver. CT scans can also be used to evaluate response of the cancer to treatment.
Author: Miriam P. Rogers, EdD, RN, AOCN, CNS Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
