The symptoms of cancer are complex and varied, and different cancers have different manifestations, so it is difficult to explain them in a few words. For example, cough, hemoptysis and lung infection caused by lung cancer; blood in stool, abdominal pain and diarrhea caused by intestinal cancer; lymphoma causing palpable lumps in superficial parts of the body, etc. 3. Symptoms caused by distant metastasis of cancer, such as fracture and bone pain caused by bone metastasis of cancer; ascites or pleural fluid caused by pleural or peritoneal metastasis of cancer; headache, weakness of limbs, even coma and paralysis caused by brain metastasis of cancer, etc.