Blood tests. Tests of blood to measure organ functions may reveal whether other organs, including the liver, may be affected by cancer. Scanning tests. PET and CT scans are two types of tests. Endoscopic ultrasound. Endoscopic ultrasounds involve passing a thin tube with a camera down your throat and into your stomach. Images of your stomach are created using an ultrasound tool. Through an endoscopy, doctors can determine how deeply cancer penetrates the stomach wall. Exploratory surgery. If your cancer has spread outside of your stomach or into your chest or abdomen, your doctor may recommend surgery. Laparoscopic exploration is typical of exploratory surgery. A small incision is made in your abdomen and a camera is inserted that transmits images to a monitor.