The lack of appetite and desire to eat may not necessarily be due to cancer, but the specific cause needs to be confirmed by gastroscopy, chest and abdominal CT, tumor markers, thyroid function and other related tests. There are many reasons for lack of appetite, such as mental and psychological factors, indigestion caused by gastric motility disorder, or cold and fever, which may affect appetite. In addition, gastric cancer may also cause poor appetite. In some patients, cancer cells invade the normal stomach wall cells, resulting in abnormal gastrointestinal function, and such abnormality may lead to decreased appetite. However, some patients with gastric cancer may also show increased appetite because the tumor cells grow faster in the early stage, which stimulates the secretion of hormones and gastric acid in the stomach, thus causing increased appetite. When epigastric discomfort and sudden increase or decrease of appetite occur, patients should pay enough attention and go to gastroenterology department for gastroscopy and other related examinations in time to clarify the diagnosis and deal with the symptoms.