My husband just felt some cramping in his stomach area after a work out. It came and went over the course of a few months - it took him 5 months to go get an endoscopy because it wasn’t that bad or frequent. At that point it was far too late. The cramping was caused by a “gargantuan bleeding tumor” (in the words of the doctor). He had a whipple the next month, followed by 3 years of intense chemo and other unpleasantness before he passed away. The doctor originally gave him 12-18 months.