Stomach cancer. Coloured barium X-ray of the stomach (dark red, upper to lower centre) of a patient suffering from gastric cancer. The cancer causes the stomach to have a ragged appearance. Gastric cancer is a common cancer of the digestive tract. It causes difficulty in swallowing, nausea, vomiting, abdominal pain, heartburn and weight loss. Treatment includes surgery to remove the cancer and the affected parts of the stomach, often accompanied by radiotherapy and chemotherapy (anti-cancer drugs).