What are the symptoms adenocarcinoma of stomach and how detected?

Variable ,EGD/biopsy. Symptoms will vary- from being asymptomatic with only some stomach discomfort, bloathing, upset stomach, to early satiety ( feeling full easily even with a very little food), nasuea, vomiting, severe pain, obstruction, weight loss, vomiting blood etc. It is detected by doing an upper endoscopy and biopsy to the lesion on the stomach. Once diagnosis is made- some imaging need to be done for staging.