At present, there are four ways of clinical application of tumor chemotherapy. 1.Radical chemotherapy Tumors that are sensitive to chemotherapy and can be cured or completely controlled by systemic chemotherapy are often treated with radical chemotherapy, such as choriocapillary epithelial carcinoma, acute leukemia, malignant lymphoma, testicular tumor, nephroblastoma, neuroblastoma and embryonal rhabdomyosarcoma and other malignant tumors. In recent years, it has been gradually recognized that the efficacy of these tumors is closely related to the dose intensity. Since the introduction of recombinant human granulocyte colony-stimulating factor and granulocyte-monocyte colony-stimulating factor (rhG-CSF and rhGM-CSF) into clinical use in 1989, coupled with the application of self-bone marrow transplantation and peripheral hematopoietic stem cell transplantation, it has become possible to improve the efficacy of chemotherapy by high or super conventional dose chemotherapy, especially for tumors with curative potential, and has attracted increasing attention from oncologists. 2. Adjuvant chemotherapy and neoadjuvant chemotherapy are the chemotherapy that is administered after effective local treatment (surgery or radiotherapy) to prevent recurrence of metastases, for example, adjuvant chemotherapy after osteosarcoma surgery can significantly improve the efficacy and help some patients avoid amputation. In high-risk breast cancer patients, postoperative adjuvant chemotherapy can improve survival and disease-free survival rates. Neoadjuvant chemotherapy, also known as induction chemotherapy or initiation chemotherapy, is administered prior to local treatment with surgery or radiation therapy in the hope of reducing local tumor size after chemotherapy, reducing the extent of surgery and removing or suppressing possible microscopic metastases. Neoadjuvant chemotherapy has been shown to reduce the extent of surgery and disability in breast cancer, laryngeal cancer, osteosarcoma and soft tissue sarcoma, and has also suggested possible benefits in non-small cell lung cancer, esophageal cancer, nasopharyngeal cancer and other head and neck tumors. 3.Palliative chemotherapy For patients with advanced or disseminated cancer, there is usually a lack of other effective treatment methods and systemic chemotherapy is often used at the beginning, but the palliative effect of chemotherapy for this family of patients is limited and the immediate goal is to achieve remission. If the first-line chemotherapy regimen used at the beginning fails, it needs to be replaced with other second- or third-line chemotherapy regimens, often called remedial chemotherapy. 4.Local chemotherapy ① Intrathoracic, intrapericardial and intraperitoneal chemotherapy for cancerous exudate; ② Intrathecal administration through lumbar puncture, commonly used for the treatment of meningeal leukemia or lymphoma; ③ Arterial cannulation chemotherapy, hepatic artery cannulation is used for the treatment of primary hepatocellular carcinoma and hepatic metastatic carcinoma that cannot be surgically resected. External carotid artery branch cannulation can be used for the treatment of head and neck cancer and intracranial tumors; ④ Intra-tumor injection.