My wife (43) was diagnosed with Stage IV stomach cancer that had spread to her liver. The original diagnosis came from an endoscopy in which they took tissue samples and she received the diagnosis of stomach cancer. From their the next test was a CT Scan and that is when they discovered a spot on her tumor; this was later confirmed by taking a biopsis of this area by actually inserting a needle into her liver where the spot was and taking a sample. During this time she also went in for an ultrasonic endoscopy where they identified that the stomach tumor had gone through 3 of the five layers of the stomach; in this test they actuall send a small thing into your stomach that takes something that resembles an xray and shows how far through the wall of the stomach the tumor had grown. These are all very minor scanning and testing techniques but the cost does grow fast.
Since it was Stage IV when we discovered it, the option of surgery was not as appealing as chemotherapy so there is some importance in knowing the extent before attempting a surgical intervention. Keep on researching and seek out a second opinion. Perhaps a case worker at the VA can assist - even if you have to travel to another VA to receive the testing.
Good Luck, keep us posted.