Stomach cancer is also known as gastric cancer. It begins when cancer cells form in the inner lining of the stomach wall. The cancer can form an ulcer or a mass within the stomach and it can spread diffusely throughout the entire wall of the stomach.
How common is Stomach Cancer?
Stomach cancer is the 7th most common cancer in males in Singapore and the 9th most common cancer among females in Singapore. There is a decreasing trend in the incidence of this cancer. The incidence 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.
Most people present with non-specific complaints, such as abdominal discomfort, indigestion, bloated after a meal, nausea or vomiting. Early symptoms could be very similar to gastritis. Patients may also look pale and feel tired because of blood loss from the cancer. When the cancer progresses, late complications may include obstruction of the gastric outlet, and more significant loss of appetite and weight.
Have a diet with low salt and plenty of fruits and vegetables is protective against gastric cancer. Avoid smoking and second-hand smoke.
Longstanding inflammation in the inner lining of the stomach (chronic gastritis) caused by infection with a bacterium called Helicobacter pylori results in epithelial cell damage with increased free radical generation, leads eventually to development of cancer. The vast majority of people who have this bacterium do not develop stomach cancer. However, H. pylori eradication therapy is recommended for patients who have H. pylori infection as treatment for H. pylori appears to reduce the risk of stomach cancer.
An increased risk of stomach cancer is associated with diets containing large amounts of fried food, smoked foods, salted fish, processed meat, and pickled foods. These food damages stomach mucosa and increases the susceptibility to carcinogenesis 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.
To identify the cause of symptoms, doctor will ask about the patient's medical history, does a physical exam, and may order laboratory studies such as complete blood count to check amount of haemoglobin.
Upper endoscopy is the most important procedure to check for abnormal areas in the esophagus, stomach, and duodenum. An endoscope is a thin fiber-optic tube, is passed through the mouth and down the throat into the esophagus.
Although uncomfortable, this procedure lasts only about 10 to 20 minutes. It is done as an outpatient procedure under light anaesthesia. When there are abnormalities found such as ulcer or lump, a biopsy or a small piece of tissue from the stomach will be taken, which is then examined under a microscope to determine if the ulcer or lump is cancerous or non-cancerous.
Once stomach cancer is diagnosed, CT scans of the abdomen are required to see if the cancer has spread elsewhere.
Surgery is the only effective curative method in the treatment of early stomach cancer. Surgery involves removal of the part of the stomach that contains cancer (partial gastrectomy) or entire stomach (total gastrectomy), nearby lymph nodes, and parts of other tissues and organs near the tumor. In certain patients with advanced stomach cancer, sometimes surgery is performed to reduce complications of the cancer such as blockage of the stomach or bleeding from the cancer.
After surgery, chemotherapy with or without radiotherapy is sometimes given to to patients to reduce the chance of cancer recurrence and to improve the chance of surviving 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 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. Alternatively, clinical trials with novel drugs are usually available as an option for patients.
Targeted therapy is a type of treatment that uses drugs to identify and attack specific cancer cells. For stage IV stomach cancer and stomach cancer that has recurred, targeted therapy may be given together with chemotherapy to improve the treatment efficacy. The immunotherapy drug might also be an option at some point for selected patients.
Patients with operated stomach cancer without lymph node involvement have a more than 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.