Symptoms of mid-stage gastric cancer can include nausea, vomiting, poor appetite, decreased food intake, and upper abdominal pain, as well as symptoms related to the digestive tract. Some patients may also experience black stool or even vomiting blood, which are symptoms of upper gastrointestinal bleeding. Additionally, there can be bloating and abdominal pain. If the tumor is located near the pylorus and causes pyloric obstruction, clinical symptoms will include vomiting, vomiting of overnight food, and resulting in gastric retention. This can lead to significant symptoms such as abdominal pain, bloating, acid reflux, and nausea.