Stomach Cancer

What is Stomach Cancer?

Stomach cancer (also known as gastric cancer) starts in the stomach. It is the 7th most common cancer in Singaporean males and 9th most common cancer in Singaporean females.¹ In Singapore, there are approximately 18.1 cases of stomach cancer per 100,000 person-years.

Stomach cancer used to be the leading cause of cancer deaths in the world until the 1980s, when lung cancer overtook it. It is thought that this change could be due to the invention of refrigeration technology, which led to a reduction in consumption of salt-preserved food.

However, stomach cancer is a diverse disease, and among the different types of stomach cancer, there has been an increase in cancer arising in the proximal (front) part of stomach and a decline in cancer arising in the distal (back) part of the stomach. The most common type of stomach cancer is adenocarcinoma. Rarer types include gastrointestinal stromal tumour (GIST), lymphoma and carcinoid.

What are the Risk Factors of Stomach Cancer?

Gender: Stomach cancer is more common in males than in females.
Age: The peak incidence for stomach cancer is between 60–80 years old.
Environmental Factors: Incidence of stomach cancer is approximately 4 times higher in Japan and Korea than in Singapore². Most of the cases that clusters within the family are probably due to shared environmental risk factors such as a diet high in salt-preserved food, such as salted fish and nitroso containing compounds such as processed meat.
Familial Risk: It is estimated that only 1–3% of stomach cancer is due to a history of stomach cancer in the family.
Obesity
Certain Infections: Helicobacter Pylori Infection or Epstein Barr Virus infection
Smoking

What Can Be Done to Prevent Stomach Cancer?

Eat less salt-preserved food and processed meat
Increase intake of fruits and vegetables
Reduce weight
Stop smoking
Treat Helicobacter Pylori treatment if it is detected
Gastric Cancer Screening

What are the Signs and Symptoms of Stomach Cancer?

Early-stage stomach cancer rarely causes symptoms. For this reason, most stomach cancers are not detected in the early stage. Early symptoms of stomach cancer are often general in nature, including:

Indigestion
Feeling bloated after eating (even after a small meal)
Heartburn
Frequent Burping
Stomach ache or pain in the breastbone
Loss of appetite
Persistent, or unexplained nausea

Alarming symptoms of stomach cancer may include:

Swallowing difficulty (Dysphagia)
Vomiting blood
Blood in your stool, or black stool (a sign of stomach bleeding)
Anaemia (a reduced number of red blood cells that cause you to feel tired and breathless)
Unexplained weight loss
Swelling of abdomen

Most of these symptoms are more likely to be caused by things other than cancer, such as a stomach virus or an ulcer. They may also occur with other types of cancer. However, people who have any of these problems that persist or worsen should check with their doctor to determine the cause. Any of the alarming symptoms above should also prompt a thorough medical check.

How to Screen for Stomach Cancer?

In countries such as Japan and Korea, where the incidence of stomach cancer is almost 4-fold higher, national screening programs offer patients aged 50–70 a gastroscopy once every 2–3 years or double-contrast barium radiography yearly. This has led to the identification of many cases at an early, curable stage. There are however no national stomach cancer screening programmes in Singapore.

1. Gastroscopy

Gastroscopy (also known as an upper endoscopy) is a nonsurgical procedure where an endoscope is passed through the mouth and into the stomach. The endoscope is a thin, flexible tube with a light and camera attached to it, allowing your doctor to examine your digestive tract for any abnormalities.

2. Double-Contrast Barium Radiographs

A double-contrast barium radiograph consists of a series of x-rays of your esophagus and stomach. It is done by consuming a liquid containing barium, which appears white on X-ray. The barium coats the inside walls of your esophagus, stomach and intestines, making them stand out more clearly in the x-rays. Air is also often inserted from the bowel to further enhance the x-ray, so that even small abnormalities will show up. These types of procedures are thus referred to as a double-contrast barium radiograph. The resulting x-rays will be made into a film, so your doctor can examine the lining of the tract for any abnormalities.

3. Blood Tests

More convenient stomach cancer screening using a blood-based test kit has been developed and may be adopted more widely in the future.

Stomach Cancer Diagnosis

How do I confirm if I have stomach cancer?

Stomach cancer is diagnosed by endoscopy with biopsy. The doctor first passes an endoscope into your upper gastrointestinal tract, just as in a gastroscopy procedure. A biopsy is then done by removing a sample of the identified stomach tissue, for analysis in the lab. If the biopsy confirms that cancer is present, a full medical assessment with blood tests and CT or PET scan will be conducted to determine the cancer stage. This information will then guide the doctor as he/she plans the treatment.

Stomach Cancer Treatment at The Cancer Centre, Singapore

How Is Stomach Cancer Treated?

Surgery remains as a key treatment of localised gastric cancer (i.e. stomach cancers that have not spread outside of the stomach or to the adjacent lymph nodes). The surgery can be performed either via open or laparoscopic (key-hole) approaches. The type of surgery depends on the part of the stomach where the cancer is in and the extent of the cancer within the stomach. Rarely, very early-stage cancer confined to the mucosa lining may be removed by endoscopic surgery. More commonly, stomach cancer surgery involves either:

Total gastrectomy (for upper stomach cancer)
Partial gastrectomy (for lower stomach cancer)

Gastric cancer surgery should also include extended D2 lymph node dissection to improve long-term cancer outcome. <h5″>What are the success rates for surgical stomach cancer treatment? Data from East Asian centres show that surgical treatment alone for stage 2 and stage 3 gastric cancer had a 40% risk of relapse at 3 years³. Addition of chemotherapy after surgery significantly improved the odds of long-term cure by 32–44%^{3, 4}. Chemotherapy treatment for stomach cancer may be better tolerated prior to surgery in most patients. However, new and efficacious protocols have been developed in Europe, whereby combination chemotherapy (administering chemotherapy before and after surgery⁵) improved patient outcome.

b) Treating advanced stomach cancer

Combination chemotherapy improves symptoms and survival rate in metastatic (advanced) gastric cancer. Trials have shown that even elderly patients benefit as much from dose-attenuated chemotherapy as younger patients. General side effects of chemotherapy include fatigue, nausea, vomiting, sore mouth, and increased risk of infection. Specific chemotherapy medicine may cause hair loss, diarrhoea or numbness of small nerves. For patients who test positive for HER2 in their tumour specimen, the addition of targeted therapy against HER2 significantly improves the outcome. For patients who have failed one prior line of chemotherapy, adding targeted therapy against vascular endothelial growth factor to chemotherapy enhances the benefit of treatment. Immunotherapy may bring profound benefit in a subset of patients who have failed chemotherapy. Combination of immunotherapy with chemotherapy is being explored as the front-line strategy and treatment for metastatic gastric cancer in Singapore. Visit The Cancer Centre in Singapore for stomach cancer screening and treatment options.

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