Signs and symptoms of gastroesophageal junction cancer and stomach cancer may include:

• Fatigue
• Feeling bloated after eating
• Feeling full after eating small amounts of food
• Severe, persistent heartburn
• Severe indigestion that is always present
• Unexplained, persistent nausea
• Stomach pain
• Persistent vomiting
• Unintentional weight loss

In general, cancer begins when an error (mutation) occurs in a cell's DNA. The mutation causes the cell to grow and divide at a rapid rate and to continue living when a normal cell would die. The accumulating cancerous cells form a tumor that can invade nearby structures. And cancer cells can break off from the tumor to spread throughout the body.

Gastroesophageal junction cancer is associated with having gastrointestinal reflux disease (GERD) and, less strongly, with obesity and smoking. GERD is a condition caused by frequent backflow of stomach acid into the esophagus.

There is a strong correlation between a diet high in smoked and salted foods and stomach cancer located in the main part of the stomach. As the use of refrigeration for preserving foods has increased around the world, the rates of stomach cancer have declined.

The main risk factors for gastroesophageal junction cancer are a history of GERD and obesity.

Factors that increase your risk of stomach cancer located in the stomach body include:

• A diet high in salty and smoked foods
• A diet low in fruits and vegetables
• Family history of stomach cancer
• Infection with Helicobacter pylori
• Long-term stomach inflammation
• Pernicious anemia
• Smoking
• Stomach polyps