The stomach is an organ between the esophagus and the small intestine. It mixes food with stomach acid and helps digest protein. Stomach cancer mostly affects older people - two-thirds of people who have it are over age 65. Your risk of getting it is also higher if you
Have had a Helicobacter pylori infection
Have had stomach inflammation
Are a man
Eat lots of salted, smoked, or pickled foods
Smoke cigarettes
Have a family history of stomach cancer
It is hard to diagnose stomach cancer in its early stages. Indigestion and stomach discomfort can be symptoms of early cancer, but other problems can cause the same symptoms. In advanced cases, there may be blood in your stool, vomiting, unexplained weight loss, jaundice, or trouble swallowing. Doctors diagnose stomach cancer with a physical exam, blood and imaging tests, an endoscopy, and a biopsy.
Because it is often found late, it can be hard to treat stomach cancer. Treatment options include surgery, chemotherapy, radiation or a combination.
NIH: National Cancer Institute