Stomach Cancer

What is stomach cancer?

Stomach cancer is a disease that begins in the stomach, the part of the digestive system which contains, breaks down and digests the food we eat. It is a hollow, muscular organ shaped like a large pouch, located in the upper abdomen, under the ribs. The upper part of the stomach connects to the oesophagus and the lower part leads to the small intestine. Stomach cancer, which is also known as gastric cancer, can affect any part of the stomach.

How stomach cancer forms and spreads 

Stomach cancer forms when cells in the stomach mutate in a way that cause them to grow and divide abnormally causing an ulcer or a mass to form within the stomach. The mass or tumour can eventually spread through the entire wall of the stomach and spread to other parts of the body. 

Prevalence of stomach cancer 

Stomach cancer is the 8th most common cancer in males in Singapore and the 10th most common cancer among females in Singapore. It more commonly occurs in men and in individuals aged between 50 and 70 years old. 

Types of stomach cancer 

There are different types of stomach cancer, classified by cell type and where the cancer begins. 

• Adenocarcinoma: The most common type of stomach cancer, which accounts for 90-95% of stomach cancers, is adenocarcinoma, which starts in the glandular cells of the stomach lining.
  
  Adenocarcinoma may also be classified based on how they look under the microscope – intestinal and diffuse subtypes. Diffuse adenocarcinomas tend to grow and spread more aggressively and are harder to treat. 
• Gastrointestinal stromal tumours (GIST): GIST is a rare type of soft tissue sarcoma, which forms in the interstitial cells of Cajal (cells in the gastrointestinal tract) and other digestive organs. 
• Gastric lymphoma: A cancer of the immune system that forms in the stomach wall. They can be mucosa-associated lymphoid tissue (MALT) gastric lymphoma or diffuse large B-cell lymphoma of the stomach. 
• Neuroendocrine tumours or carcinoid tumours: Cancer which starts in the neuroendocrine cells, nerve-like and hormone-producing cells, of the stomach.