One early sign of stomach cancer is microscopic internal bleeding, which is usually only detected by tests that check your stool for blood. You may also feel tired if this bleeding causes the loss of too many healthy red blood cells (anemia). Early stomach cancer may also cause symptoms such as heartburn and abdominal pain, which can be mistaken for other, more common problems.

When the cancer is more advanced, you may experience signs and symptoms such as:

• Discomfort in the upper or middle region of your abdomen that may not be relieved by food or antacids (In the early stages of stomach cancer, pain is often relieved by food or acid-buffering medications.)
• Abdominal discomfort aggravated by eating
• Black, tarry stools
• Vomiting blood
• Vomiting after meals
• Weakness and fatigue
• Unintended weight loss
• Full feeling after meals, even when eating less than normal

Having one or more of these signs and symptoms doesn’t necessarily mean you have stomach cancer. Other more common conditions, especially peptic ulcers, can cause similar problems.