Stomach cancer


Stomach cancer has been declining in the United States for many years, possibly due in part to changes in the American diet. But the disease still affects about 26,000 people a year in this country, and rates are higher in other parts of the world. 

Seattle Cancer Care Alliance (SCCA) offers comprehensive stomach cancer treatment from a team of experts who specialize in gastrointestinal cancers.

What is stomach cancer?

Stomach cancer, also called gastric cancer, forms in tissues that line the stomach. 

Cancer occurs when cells begin to grow abnormally. They do not respond to regular cell growth, division and death signals like they are supposed to. They also don’t organize normally. Instead they grow into a tumor, which may break through surrounding layers of cells.


Most stomach cancers — 90 to 95 percent — are adenocarcinomas, cancers that develop from cells that line many organs. 

Other types of stomach cancer include squamous cell carcinoma, lymphoma and stromal tumors (cancers of the muscle or connecting tissue). 

A rare gastrointestinal cancer, carcinoid tumor, develops when malignant cells are found in certain hormone-making cells of the digestive system or in the inner lining of this system.


Stomach cancer is difficult to discover in its early stages because the symptoms are often similar to other conditions, like indigestion or a viral infection.

  • Unintended weight loss and lack of appetite
  • Stomach pain
  • Bloated feeling after eating
  • Heartburn
  • Nausea
  • Vomiting
  • Swelling of the abdomen
  • Diarrhea or constipation
  • Blood in vomit or stool


If your doctor suspects you might have stomach cancer, the doctor will examine you, ask about your medical history and ask for lab tests, such as a blood test or a fecal blood test to look for blood in your stool.

You may also need one or more of these imaging studies:

  • Barium X-ray — taken after you drink a liquid contrast agent that helps your stomach show up on the X-ray
  • Gastroscopy or endoscopy — inserting a thin tube with a camera at the end through your mouth into your stomach to see the lining of your stomach, esophagus and small intestine and maybe take tissue samples
  • Endoscopic ultrasound — inserting a thin tube with an ultrasound probe at the end through your mouth into your stomach to create a picture with sound waves and see how far the cancer may have spread
  • Laparoscopy — inserting a thin tube with a camera at the end through a small incision in your abdomen to see if cancer has spread outside your stomach
  • Chest X-ray — to see if cancer has spread to your lungs
  • Computed tomography (CT) scan or magnetic resonance imaging (MRI) — which creates cross-sectional images to help determine if cancer has spread to your liver, lymph nodes or elsewhere

What causes stomach cancer?

Stomach cancer was once one of the leading causes of cancer deaths in the United States. but not any more.

Doctors and researchers are not sure why but think the decline may result from lower intake of salt and smoked foods, which are more likely to contain cancer-causing nitrates. Stomach cancer is more common in Japan, Korea, parts of Eastern Europe and Latin America, where people preserve many foods by salting, smoking or pickling.

Another reason for the decline in stomach cancer is increased use of antibiotics to treat infection with Helicobacter pylori bacteria, which may be a major cause of the disease.

Other risk factors for stomach cancer include:

  • Smoking
  • Alcohol abuse
  • Previous stomach surgery (such as the removal of stomach tissue due to an ulcer)
  • Blood type A
  • Age older than 50
  • Family history of stomach cancer
  • Stomach polyps
  • Menetrier's disease, linked with low levels of stomach acids 
  • Rare conditions, such as Lynch syndrome or familial adenomatous polyposis

Preventing stomach cancer

SCCA’s Gastrointestinal Cancer Prevention Program offers a personalized approach to risk assessment, screening and prevention for people at high risk for stomach cancer and other gastrointestinal cancers. 

How common is stomach cancer?

About 26,000 people are diagnosed with stomach cancer in the United States each year. People over 50 are more likely to develop the disease; it occurs most often in people in their 60s and 70s.