Indications for medical oncology treatment: systemic malignant tumors sensitive to chemotherapy, such as leukemia and multiple myeloma patients with advanced disseminated tumors or relapsed metastases after surgery or radiotherapy who have no indication for surgery or radiotherapy patients with tumors that are less effective in chemotherapy can adopt special routes or special methods of drug delivery in order to obtain better efficacy, such as primary hepatocellular carcinoma treated with intervention cancerous thoracic, abdominal and pericardial effusions. Intracavitary drug delivery is adopted. Patients with tumor-induced superior vena cava compression, airway compression, and intracranial hypertension can have their symptoms reduced by chemotherapy. Patients with chemotherapy and biotherapy indications, and patients who need adjuvant chemotherapy before and after surgery. Reasons for failure of chemotherapy: Patient side: Insufficiency of bone marrow and other vital organs (liver, spleen, kidney), general condition too poor to tolerate treatment. On the tumor side: primary or secondary drug resistance; reduced proliferation ratio; excessive tumor load. Drug side: not very selective; ineffective or less effective against G0 stage cells; unable to act on tumor cells in the “sanctuary”. Tumor drug resistance Drug resistance is one of the most important factors affecting the effectiveness of chemotherapy. The mechanisms are complex: impairment of drug transport or uptake, impairment of drug activation, qualitative and quantitative changes in target enzymes, increased use of endothelical metabolic pathways, increased use of endothelical enzymes, increased repair mechanisms, increased cellular excretion of drugs due to increased specific membrane glycoproteins, decreased inter- or intra-strand cross-links, decreased hormone receptors or loss of function. Antitumor drug resistance is a complex problem that involves many aspects of basic and clinical research. Different tumor cells may have different resistance mechanisms to the same drug, and a single tumor may develop multiple resistance mechanisms to a single drug. In order to successfully overcome tumor drug resistance in clinical practice, the drug resistance mechanism of that tumor should be determined first, and multiple antagonists or therapies should be applied in combination if necessary. Strategies to improve the efficacy of medical therapy Searching for new drugs with new mechanisms of action Developing highly effective and less toxic derivatives of known drugs Overcoming drug resistance genes Increasing the dose intensity Targeting new targets Improving the route of administration Rebuilding the patient’s immune function through biological response modifiers Rebuilding the normal bone marrow function through hematopoietic stem cell transplantation Gene therapy Chemosensitizers Integrative tumor therapy Rational and planned integrative therapy has achieved good efficacy in a considerable number of tumors. In the past 30 years, integrated therapy has replaced traditional monotherapy and improved the cure rate in many tumors. The principles of combination therapy: clear purpose, arrange the sequence in accordance with tumor biology The patient’s organism condition: especially how is the bone marrow function and immunity, and how is the comparison with tumor. Limited versus disseminated, which is the main threat (or the first problem to be addressed). The benefit or burden of treatment to the patient Arrangements should be reasonable. It is also important to develop a rational and planned comprehensive treatment plan with adequate weighing of positive and negative, limitation and dissemination, which requires thorough discussion and consultation among physicians from many disciplines. Several models of comprehensive treatment Traditional model: i.e. surgery first for more limited tumors, followed by radiotherapy and/or chemotherapy later depending on the surgery. Breast cancer is a successful example. Preoperative radiotherapy: For patients with locally advanced tumors or those with regional lymph node metastases, chemotherapy or radiotherapy can be done first and surgery can be performed later. For some tumors that are locally advanced but do not yet have distant metastases, this modality often results in better outcomes. There have been many examples of inoperable patients being made operable through chemotherapy and/or radiotherapy, most notably in small cell lung cancer. Simultaneous radiotherapy, the so-called Ewing’s tumor model The arrangement of radiotherapy and chemotherapy for inoperable patients is mostly advocated for chemotherapy first, or chemotherapy and radiotherapy at the same time. Vascular occlusion due to fibrosis after radiotherapy makes it difficult for chemotherapy drugs to enter.