Stomach (Gastric) Cancer
What is Stomach Cancer?
Any of the cells lining the inner wall of the stomach can become cancerous. The cancer can form a mass or ulcer within the stomach or it can spread diffusely throughout the entire wall of the stomach. Stomach cancer is also called gastric cancer.
How common is Stomach Cancer?
Stomach cancer is not uncommon in Singapore. It is the third most common cancer in males in Singapore and the fifth most common cancer among females in Singapore. There is a decreasing trend in the incidence of this cancer. However, rates in Asia are among the highest in the world.
Age of Onset
Stomach cancer is commonly found in people aged between 50 and 70 years of age. It is more common in men.
Risks and Causes
Patients with stomach cancer have a higher rate of infection with a bacterium called Helicobacter pylori. However, the vast majority of people who have this bacterium in their stomachs do not develop stomach cancer.
An increased risk of stomach cancer is associated with diets containing large amounts of smoked foods, salted fish and meat, and pickled foods. On the other hand, eating fruits and vegetables high in Vitamin A and C appear to lower the risk of stomach cancer.
Nitrites and nitrates are substances commonly found in cured meats. These can be converted by some bacteria into compounds which can cause cancer in animals. This has not been proven in humans.
Symptoms and Signs of Stomach Cancer
Most people present with non-specific complaints, such as abdominal discomfort or indigestion. Occasionally, because the cancer forms a mass in the stomach it can block the passage of food ingested. There may be vomiting subsequently. Patients may also present with symptoms of anaemia because of blood loss from the cancer.
Diagnostic Tests
Routine blood tests showing anaemia or a lack of red blood cells would raise the suspicion of the doctor. Another sinister finding would be the presence of blood in the faeces.
Barium meal x-ray examination is able to detect stomach cancer. During this examination, the patient swallows liquid containing barium. X-rays are then taken to delineate the outline of the stomach wall. Ulcers and lumps can be detected. Endoscopy or the passage of a fiber-optic scope into the stomach through the mouth is then required so that a biopsy can be taken. Although uncomfortable, this procedure lasts only about 10 to 20 minutes. It is done as an outpatient procedure under light anaesthesia. A biopsy or removal of small amount of tissue, which is then examined under a microscope, will show if the ulcer or lump is cancerous or non-cancerous. Endoscopy is generally more accurate than a barium meal x-ray examination.
Once stomach cancer is diagnosed, chest x-rays and CT scans of the abdomen are required to see if the cancer has spread elsewhere.
Treatment of Stomach Cancer
Surgery is the only effective curative method in the treatment of stomach cancer. Even in certain patients with advanced stomach cancer, surgery is performed to reduce complications of the cancer such as blockage of the stomach or bleeding from the cancer.
Radiotherapy is useful for relieving stomach obstruction in patients with advanced stomach cancer. Radiotherapy may also be used to stop bleeding from cancers that cannot be operated on. It is given over 5 minutes every day for 2 to 5 weeks. There may be temporary loss of appetite, nausea, and pain in the radiated site.
Chemotherapy is sometimes used to reduce symptoms from an advanced cancer or to prolong the time to growth of the cancer. Many chemotherapy drugs are available, most of them with side effects such as temporary nausea, vomiting, hair loss, and lowering of the white blood counts.
Recently, chemotherapy combined with radiotherapy after surgery for some early stage stomach cancers was shown to significantly reduce the chance of a stomach cancer recurring and, hence, improve the chance of surviving stomach cancer. However, this treatment is not recommended for everybody with stomach cancer. Some people with early stage stomach cancer have such a low risk of cancer recurring that additional treatment after surgery is not required.
Prognosis of Stomach Cancer
Patients with operated stomach cancer without lymph node involvement have a 50% chance of being cured from cancer after surgery. However, if the cancer spreads through the wall of the stomach to involve the normal fat around the stomach, the chance of cure decreases. Once lymph nodes surrounding the stomach are involved by the cancer, even after surgical removal of all cancer, only about 15 to 20% of patients will be alive without cancer at 5 years.
Frequently Asked Questions about Stomach Cancer
1. A few of my blood relatives have stomach cancer. Am I at higher risk?
People with a family history of stomach cancer have a slightly higher risk of developing stomach cancer. It is recommended that you mention your family history of stomach cancer to your physician everytime you seek a medical opinion.
2. I have a blood relative with colon cancer. Do I stand a higher risk of stomach cancer?
A hereditary condition, known as familial adenomatous polyposis (FAP), predisposes a person to colon cancer. People with FAP also stand a slightly higher chance of stomach cancer.
3. I get gastric pain very often. Should I go for screening for stomach cancer?
Persistent gastric pain should be investigated further especially if there is associated weight loss, anaemia or lack of red blood cells, presence of blood in the faeces, or family history of stomach or colon cancer.
Prevention:
Have a diet with plenty of fruits and vegetables, and low salt intake. Avoid smoking and second-hand smoke.
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