Hi My dad went to the hospital and they didn't know at first they did a Colonscopy and i dont remember the other exam that they do through his mounth with a little camera and notice that he has ulcers they tested and it was cancer they did the Catscan and they knew spread to the stomach but they just keep guessing on what stage. they finally told us how much of stomach they removed and what stage he is until cirugy.
I'm sorry to say but i think you won't know until they get in there ,before cirugy will be guess only. My father is on stage 3 advance and they removed 70% of stomach.