Stomach cancer mostly affects older people - two-thirds of people who have it are over age 65. 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.
Sources
MedlinePlus - Stomach cancer
