Experiencing early fullness after eating small amounts—known as early satiety—can sometimes be a warning sign of stomach cancer, especially if it occurs alongside unintentional weight loss, persistent nausea, abdominal discomfort, or bloating. While mild fullness can result from common digestive issues like indigestion or gastritis, persistent or worsening symptoms should prompt medical evaluation. A doctor may recommend tests such as endoscopy, imaging, or lab work to identify the underlying cause and ensure timely diagnosis.