Gastric cancer (or stomach cancer) begins when there is abnormal growth of cells in the stomach which then leads to a tumor. This type of cancer starts from the common cell types present in the lining of the wall of the stomach and develops gradually. It can spread to other parts of the body.

Gastric cancer has five stages – from stage 0 to stage IV. Stage 0 and Stage I are the early stages of this cancer. Stage II is the middle stage, and stage III and stage IV are the late stages of the disease. The proper staging of cancer often helps in deciding the appropriate course of treatment. There are 5 main types of gastric cancer as described below:

Adenocarcinoma:

 This type of gastric cancer is the most common type of the disease. About 90 to 95 percent of gastric cancer cases are of this type. In this, the cancer develops in the glandular calls of the stomach. These gland cells produce stomach juices and mucus.

Lymphoma:

This is a different type of cancer altogether, and is very rare. In this, the cancer begins in the lymph nodes and lymphatic system, and develops in the immune system tissue of the stomach’s wall.

Gastrointestinal Stomal Tumors (GIST):

 This type of gastric cancer develops in the cells of the connective tissues which support the various organs of the gastrointestinal tract. It develops in the stomach’s wall tissues which contain a particular type of cell known as the intestinal cells of Cajal. Gastrointestinal stomal tumor (GIST) is an uncommon form of cancer and can occur at any point in the gastrointestinal tract, though most of the cases of GIST occur in the stomach. GIST may be cancerous or non-cancerous

Carcinoid Tumors:

This is yet another rare form of gastric cancer which slowly grows in the hormone-producing tissues of the stomach. Most of these carcinoid tumors do not reach out to other organs. Carcinoid Tumors can be cancerous or non cancerous. Such types of tumors occur mostly in people over the age of 60.

Squamous cell cancers:

This type of cancer develops in the squamous cells, which are the skin-like cells which lie in between the gland cells to make the lining of the stomach. These types of cancers are treated in the same way as adenocarcinomas.