The symptoms that may appear before cancer may be different in different parts of the body. Most of the symptoms may not be too typical and easy to be ignored, such as stomach cancer, which may show similar symptoms of gastritis with acid reflux, nausea, vomiting, heartburn, black stool, anemia and other symptoms. Such cases must be taken seriously and further gastroscopy is needed to confirm the diagnosis through gastroscopic biopsy pathology, and gastroscopy needs to be routinely reviewed once a year. Most of them may not have obvious discomfort symptoms, and some of them are found during lung CT in physical examination. Therefore, for the diagnosis and treatment of lung cancer, we must rely on CT lung examination, and other chest radiographs cannot replace CT lung, therefore, for the examination of cancer, we must have regular medical checkups and corresponding screening tests to diagnose it.