Comprehensive treatment of glioma is currently the most reliable means of glioma. Comprehensive treatment of glioma mainly refers to three major means: surgery, radiotherapy and chemotherapy. Radiation therapy is a treatment method that gives uniform and accurate irradiation to certain tumor tissues with a small dose to surrounding normal tissues. Radical radiotherapy is the main task of glioma radiotherapy. Although we have made great progress in the field of basic research of glioma and also have a hundred years of clinical treatment history, the overall treatment effect, especially for malignant glioma, is still unsatisfactory. The combination of surgery, radiotherapy, and chemotherapy remains the only option for glioma. The therapeutic role of radiation therapy as an indispensable treatment for glioma has long been recognized. However, there are still many questions regarding radiation therapy for glioma that need further study. Radiation therapy techniques Most patients with gliomas require surgery first, with total or partial excision followed by radiation therapy. Surgery is conducive to the development of radiotherapy treatment plan: 1. The clarification of histopathological nature and molecular pathological indexes is beneficial to the development of radiotherapy treatment plan; 2. Tumor cell volume reduction, surgical excision of tumor cells insensitive to radiotherapy, reduction of tumor volume, alleviation of tumor occupancy effect, and relief of clinical symptoms such as cranial hypertension to facilitate the smooth implementation of radiotherapy; 3. Tumor volume reduction may also reduce In general, poor blood supply and lack of oxygen cells in the center of the tumor, and the tumor is resistant to radiation, so total resection of the tumor is the simplest and most direct way to increase the effect of radiotherapy; 4. For glioma in the functional area, internal irradiation with radioactive particles can be placed when total resection is difficult, and external irradiation can be supplemented after surgery, which is also one of the ways of radiotherapy for glioma. For gliomatosis or glioma with diffuse growth should be biopsied or have internal decompression surgery to clarify the pathological type, especially through molecular pathological analysis to understand the sensitivity of the tumor to radiotherapy/chemotherapy, select chemotherapy drugs, and develop a comprehensive treatment plan. It should be noted here that for gliomas in the thalamus, brainstem and other important functional areas, blind radiotherapy/chemotherapy may be misdiagnosed and mistreated, which should be treated with great caution. The experimental radiotherapy for glioma without clear diagnosis should be prohibited. Preparation before radiotherapy 1. Actively improve the general condition of the patient. Especially, correcting anemia, controlling blood sugar and balancing electrolytes are helpful to enhance the effect of radiotherapy and reduce the reaction. Subcutaneous fluid, subdural fluid and intracranial hematoma are not absolute contraindications to radiotherapy, but the impact of these postoperative complications on radiotherapy should be evaluated. At the same time, great attention should be paid to the adjustment of the patient’s mental status, as fear and stress about the disease and treatment may lead to rapid deterioration of the organism’s condition. Therefore, strengthening psychological counseling and enhancing patients’ self-confidence is one of the indispensable preparations before radiotherapy. 2.Improve the pre-radiotherapy examination. Postoperative MR or CT is necessary. The location of the tumor will drift before and after surgery, and the clinical treatment target area (CTV) will be determined by comparing the preoperative and postoperative MR and CT imaging data. 3. Determine the treatment plan according to the available clinical information. This includes the purpose of treatment (radical radiotherapy or palliative radiotherapy) and the selection of the appropriate treatment modality (external irradiation alone or combination therapy such as chemotherapy and internal irradiation). In low-grade malignant glioma, radiotherapy is considered not only the probability of tumor control (TCP), but more importantly, the probability of normal tissue complications (NTCP). TCP depends on many factors such as tumor sensitivity to radiation, tumor size, etc. Compared to malignant gliomas, radiotherapy for low-grade malignant gliomas is more sensitive. Radiotherapy should control the tumor without causing unacceptable radiation damage to the patient, and safe and effective radiotherapy is the prerequisite and requirement, and radical radiotherapy is the goal. For malignant glioma, especially glioma, radiation resistance to radiotherapy is poor, survival time is short, and radical radiotherapy is often difficult to achieve, depending on the specific conditions of patients. For patients with many poor prognostic factors such as large postoperative tumor remnants and poor general condition, it is estimated that it is difficult to have a long survival time, so it is not necessary to extend the treatment time too long, but palliative radiotherapy, 3Gy×10f or 2.5Gy×20f, in order to improve the quality of survival without increasing the patient’s pain and to extend the survival period appropriately, so that patients can have more time to return to society and family. . Timing of radiotherapy Gliomas include: astrocytoma, oligodendroglioma, oligodendro-astrocytoma, ventricular meningioma, and glioblastoma according to their histological origin; they are classified according to their malignancy: low-grade glioma (astrocytoma) and high-grade glioma (mesenchymal and glioblastoma). Previous retrospective and prospective studies have confirmed the positive role of immediate postoperative radiotherapy in the treatment of high-grade gliomas, which significantly improves survival time and is an independent factor affecting the prognosis of high-grade gliomas. The combination of surgery and radiation therapy increases the 5-year survival rate in mesenchymal astrocytoma and prolongs survival time in glioblastoma multiforme. Therefore, surgery plus immediate postoperative radiotherapy is currently the most effective treatment for high-grade gliomas. Low-grade gliomas are relatively slow-growing, and there is no consensus on the timing of postoperative radiotherapy. Most retrospective studies have shown that the median survival time and 5-year survival rate of patients treated with immediate postoperative radiation therapy for low-grade gliomas are significantly higher than those treated with delayed postoperative radiation therapy (radiation therapy when the tumor shows signs of recurrence). While some retrospective studies showed no significant difference, delayed radiation complications were significantly higher in the group of patients treated with immediate postoperative radiotherapy, thus advocating delayed postoperative radiotherapy. A prospective multicenter clinical trial addressing this issue, conducted by the European Organization for Research and Treatment of Cancer (EORTC), has been completed, in which 311 eligible patients with low-grade gliomas were randomly assigned to either the immediate postoperative radiotherapy group or the delayed radiotherapy group and stratified according to the histologic origin of the tumor and the extent of surgical resection. There was no significant difference in the 5-year survival rate, but there was a significant difference in the 5-year progression-free survival (PFS) percentage and median time to tumor progression (TTP) of patients, and the immediate postoperative radiation therapy group was significantly better than the delayed radiation therapy group. Therefore, it has been advocated that patients with low-grade gliomas should first be categorized as high-risk or low-risk patients based on factors known to affect healing, and that immediate postoperative radiation therapy should be given to high-risk patients in order to provide further benefit, while delayed postoperative radiation therapy can be given to low-risk patients. Radiation damage Radiation is a double-edged sword, which can kill tumor cells and at the same time may cause damage to normal tissues. Therefore, it is as important to recognize and master the damage of radiation to normal tissues as it is to recognize and master the killing effect of radiation on tumors in radiotherapy of glioma. According to the theory of classical radiobiology, radiation damage to the central nervous system can be divided into three phases: 1. Acute phase: Occurs immediately after irradiation to within one month, and is rarely seen in conventional fractionated irradiation. The main clinical manifestations are headache, nausea and vomiting, and this acute injury does not seem to be closely related to the dose and volume of fractionated irradiation. Hormones may be used to relieve these symptoms. Early and late onset of injury: 1-6 months after irradiation, the pathological changes are mainly demyelination, clinical manifestations are mainly anorexia, hypermobility, drowsiness and Lhermitte’s syndrome after spinal cord irradiation. Patients in this stage are given appropriate hormone therapy, and clinical symptoms can generally disappear completely within 1-2 months. 3. Late onset phase: appears 6 months after irradiation, is progressive and often irreversible. The pathological changes are mainly demyelination, vascular occlusion, thrombosis, and finally radioactive necrosis, which can be limited or diffuse, but mostly limited to the white matter. Radiation necrosis is the most serious complication of the late late onset of the disease and is difficult to be completely cured even with symptomatic treatment such as the use of large amounts of hormones.