Merck Manual

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Quick Facts

Stomach Cancer


The Manual's Editorial Staff

Last full review/revision May 2019| Content last modified May 2019
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What is stomach cancer?

Cancer is the out-of-control growth of cells in your body. Cells are the tiny building blocks of your body. Cells specialize in what they do. Different organs are made of different kinds of cells. Almost any kind of cell can become cancerous. 

Stomach cancer is cancer that starts in your stomach.

  • Symptoms of stomach cancer include discomfort in your belly, weight loss, and weakness

  • Stomach cancer spreads easily to other parts of your body and is often deadly

  • Doctors treat it with surgery

What causes stomach cancer?

Causes include:

  • An infection in your stomach with the bacteria called H. pylori

  • Genetics (something you inherit from one or both parents)

What are the symptoms of stomach cancer?

Early symptoms are mild and you may not notice them. They include:

  • Burning belly pain

  • Fullness after a small meal

Later symptoms may include:

  • Weight loss or weakness

  • Anemia (low number of red blood cells)

  • Light-headedness

  • Throwing up blood or passing black tarry stool

Spreading cancer may cause symptoms such as:

  • Jaundice (yellow-colored skin and a yellow color to the white parts of your eyes)

  • Fluid build-up and swelling in your belly

  • Swollen lymph nodes

  • Weak bones, leading to bone fractures

How can doctors tell if I have stomach cancer?

Doctors look for stomach cancer with:

  • Endoscopy (a flexible viewing tube is passed through your throat to look in your stomach and take samples for testing)

If endoscopy and biopsy tests shows stomach cancer, doctors usually do:

  • CT scan and ultrasound of the abdomen to check if it has spread to other organs

  • Blood tests

How do doctors treat stomach cancer?

Doctors treat stomach cancer that hasn’t spread with:

  • Surgery

Removing the whole tumor before it spreads is the only chance for a cure. For stomach cancer that has spread, treatment can’t cure the disease or help someone live longer. Doctors may treat symptoms and make the person feel more comfortable with:

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