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. Gastrointestinal stromal tumors (GISTs) are uncommon but are more likely to spread. Cancer may also arise elsewhere in the body and spread to the stomach, a process known as metastasis.

Who gets stomach cancer?

About 26,000 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 Asia, and it is a leading cause of cancer-related death worldwide.

Stomach cancer is more common among men than women. The risk of developing stomach cancer goes up with age and it occurs most often in people over 65. In the United States, stomach cancer is more common among Latino, African American, Native and Asian/Pacific Islander people compared with white people.

What are the risk factors for stomach cancer?

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

Risk factors include diet, tobacco use, heavy alcohol consumptuon, obesity, family history, a history of stomach surgery or other stomach problems, having type A blood and possibly Epstein-Barr virus. Consumption cured, smoked, processed or grilled meat and fish and pickled vegetables raises the risk of stomach cancer while a diet rich in fresh fruit and vegetables lowers the risk.

Rates of stomach cancer have decreased in North America since the 1930s, perhaps because refrigeration has lessened the need to preserve foods 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 bloating
  • Loss of appetite
  • Unintentional weight loss
  • Heartburn or indigestion
  • Feeling full after a small meal
  • Nausea or vomiting
  • Fluid buildup in the abdomen
  • Anemia and fatigue.

How is stomach cancer diagnosed?

Early detection and treatment of stomach 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. Blood tests may reveal anemia, or loss of red blood cells due to internal bleeding, and fecal tests may show blood in the stool.

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, CT scans, ultrasound, PET and MRI 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, 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 more intensive treatment. A tumor biopsy sample may be tested for genetic changes or biomarkers that might affect treatment options. Gastrointestinal stromal tumors require different types of treatment.

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, leading to side effects.

Targeted therapy: Targeted drugs work against cancers with specific characteristics. For example, they may target genes that promote cancer growth or interfere with signaling pathways that regulate cell growth. Targeted therapy is often effective for eligible patients, 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-cell activity. Current immunotherapy drugs work for only a subset of patients, and it is hard to predict who will benefit.

Click here for a list of approved medications used to treat stomach cancer.

For more information on stomach cancer, visit:

American Cancer SocietyAmerican Society of Clinical Oncology

National Cancer Institute

Last Reviewed: April 28, 2022