Stomach cancer

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Cancerous tumours of the stomach

A cancerous tumour of the stomach can invade, or grow into, and destroy nearby tissue. It can also spread, or metastasize, to other parts of the body. Cancerous tumours are also called malignant tumours.

Stomach cancer usually begins in the inner lining of the stomach wall (called the mucosa). As it grows, it invades deeper into the stomach wall and then through the wall. When the tumour affects only the mucosa or submucosa (the layer of the stomach wall below the mucosa), it is known as early stomach cancer.

The most common cancerous tumour of the stomach is adenocarcinoma.


Adenocarcinoma tumours start in the gland cells that line the inner surface of some organs in the body, including the stomach. Adenocarcinoma accounts for up to 95% of all stomach cancers.

Intestinal adenocarcinoma includes 3 different kinds – tubular, papillary and mucinous adenocarcinoma. Intestinal adenocarcinoma is usually well differentiated (cells look and behave like normal cells). Cells are arranged into a pattern of tubes like the mucosa of the intestines. Intestinal adenocarcinoma affects men more than women and people who are older.

Diffuse adenocarcinoma includes mucinous, infiltrative and signet ring carcinoma. Diffuse adenocarcinoma is undifferentiated or poorly differentiated (cells don’t look or behave at all like normal cells). Cancer cells are scattered throughout the stomach lining. Diffuse adenocarcinoma is more common in people who are younger. The infiltrative type of diffuse adenocarcinoma may not form a mass (lump or ulcer). This may lead to a condition called linitis plastica where the stomach wall becomes hard and leathery.

There are other, rare types of adenocarcinoma:

  • mixed adenocarcinoma (made up of both intestinal and diffuse adenocarcinoma)
  • hepatoid adenocarcinoma
  • gastric lymphoepithelioma-like carcinoma (LELC)

Rare stomach tumours

The following cancerous tumours of the stomach are rare.


Gastrointestinal stromal tumours (GIST) start in interstitial cells of Cajal (ICCs). ICCs are specialized cells in the GI tract. They have characteristics of both smooth muscle cells and nerve cells. GISTs of the stomach may be cancerous or non-cancerous (benign). A cancerous GIST is usually treated with surgery or targeted therapy drugs such as imatinib (Gleevec) or sunitinib (Sutent).


Adenosquamous carcinoma contains features of both adenocarcinoma and squamous cell carcinoma. The prognosis of adenosquamous cell carcinoma tends to be less favourable than adenocarcinoma.

Gastric lymphomas are typically non-Hodgkin lymphomas. Mucosa-associated lymphatic tissue (MALT) lymphoma is the most common type of gastric lymphoma. Most cases of gastric MALT lymphoma are caused by an H. pylori (Helicobacter pylori) infection. Treatment for gastric MALT lymphoma associated with H. pylori is antibiotics and proton-pump inhibitors. Read more about treatment for gastric MALT lymphoma.

Gastrointestinal neuroendocrine tumours can be slow growing or aggressive. They are sometimes called carcinoid tumours. These tumours are usually treated by surgery or biological therapy such as somatostatin cogener therapy (chemicals that mimic somatostatin, a hormone that prevents the release of other hormones).