What is stomach cancer?

Cancer develops when cells grow out of control. The most common type of stomach cancer (also known as gastric cancer) is adenocarcinoma. Cancer may also arise elsewhere in the body and spread to the stomach, a process known as metastasis.

Who gets stomach cancer?

About 28,000 people in the United States are diagnosed with stomach cancer and nearly 11,000 people die from it annually, according to the American Cancer Society. It is much more common elsewhere in the world, particularly in low-income countries, and it is a leading cause of cancer-related death.

Stomach cancer is more common among men than women. The risk of developing stomach cancer goes up with age and it occurs more often in people over 50. In the United States, stomach cancer is more common among Latino/Hispanic people, African Americans and Asians and Pacific Islanders than among white people.

What are the risk factors for stomach cancer?

A major risk factor for stomach cancer is infection with Helicobacter pylori, bacteria that commonly cause stomach ulcers. Over time, infection can lead to inflammation and precancerous changes of the inner lining of the stomach.

Risk factors include tobacco smoking, diet (including cured or smoked meat and fish and pickled vegetables), obesity, a history of stomach surgery or other stomach problems, family history, pernicious anemia, having type A blood and possibly infection with Epstein-Barr virus. Some studies show that low socioeconomic status is linked with a higher rate of stomach cancer, but that may be related to other risk factors such as poor diet, increased smoking and other considerations.

Rates of stomach cancer have decreased in North America since the 1930s, likely because refrigeration has led to a fresher diet with less need for foods preserved by salting or smoking. More recently, increased use of antibiotics that kill H. Pylori may have contributed to the decrease.

What are the symptoms of stomach cancer?

The stomach is a sac-like organ just below the diaphragm that secretes gastric juices that help digest food. Many people with stomach cancer do not develop symptoms until its late stages, when it is harder to treat. The stomach is elastic, so a tumor can grow for a while without interfering with normal function or causing pain.

Symptoms may arise once the tumor grows into surrounding tissues and organs. Other health conditions can cause the same symptoms as stomach cancer and need to be ruled out in the diagnosis. Symptoms that might indicate stomach cancer include: 

  • Abdominal pain or discomfort
  • Indigestion
  • Nausea or vomiting
  • Heartburn or indigestion
  • Dysphagia (trouble swallowing)
  • Loss of appetite
  • Weight loss
  • Bloated or swollen abdomen
  • Buildup of fluid in the abdomen
  • A lump that can be felt through the abdomen
  • Anemia

How is stomach cancer diagnosed?

Early detection and treatment of cancer increases the likelihood of long-term survival. The process of diagnosis starts with a physical exam and medical history, including family history and how long symptoms have been present. The physical exam will check for abdominal lumps or swelling, and a digital rectal exam may be done to check for lumps in the pelvis. Blood tests may be ordered for substances that could indicate cancer.

An upper gastrointestinal endoscopy may be performed, in which a thin, flexible tube with a camera is inserted through the esophagus to look at the inside of the stomach and the upper part of the small intestine. If a mass is detected, a small tissue sample (a biopsy) may be removed to examine in the laboratory. X-rays, computed tomography (CT), positron emission tomography (PET), MRI or ultrasound scans may be done to see how extensive the cancer is and how much it has spread.

How is stomach cancer treated?

Treatment for stomach cancer depends on how advanced the cancer is when it is detected, including how many tumors are present, how large they are and whether they have spread to nearby lymph nodes or other parts of the body. Most cases of stomach cancer are diagnosed at a more advanced stage and require a more intensive treatment strategy.

Surgery: Some small and localized stomach tumors can be surgically removed; this is known as resection. For advanced stomach cancer, the whole stomach may need to be removed.

Radiation: Radiation may be used to kill cancer cells that remain after surgery or to shrink tumors that cannot be surgically removed. It is often used in conjunction with other forms of treatment.

Chemotherapy: Traditional chemotherapy works by killing fast-growing cells, including cancer cells. It can also destroy rapidly dividing healthy cells, such as those in the gut or hair follicles, leading to side effects like nausea and hair loss.

Targeted therapy: Targeted drugs work against cancers with specific characteristics. For example, they may interfere with signaling pathways that regulate cell growth. Targeted treatment is often better tolerated than chemotherapy, but cancer may develop resistance over time.

Immunotherapy: The newest type of treatment helps the immune system fight cancer. For example, some tumors can turn off immune responses against them, and drugs known as checkpoint inhibitors can restore T cells’ ability to recognize and destroy cancer cells. Current immunotherapy drugs work for only a subset of patients, and it is hard to predict who will benefit.

For more information on stomach cancer, visit:

American Cancer Society

National Cancer Institute

Last Reviewed: October 31, 2017