I. Abstract 1. Preferred treatment strategy for malignant glioma: surgical resection. 2. Basic principle: maximal safe tumor resection. In other words, under the premise of preserving the normal neurological function to the greatest extent, the tumor lesion should be resected to the maximum extent. (Highly recommended) Jinsong Wu, Department of Neurosurgery, Huashan Hospital, Fudan University 3. If maximal safe tumor resection cannot be performed, partial tumor resection, open biopsy or stereotactic (or under navigation) puncture biopsy can be used as appropriate to clarify the histopathological diagnosis of the tumor. (Recommended) 1. The purpose of surgery: (1) total resection of tumor; (2) reduction of tumor cell load to create favorable conditions for adjuvant radiotherapy; (3) clarification of histopathological diagnosis; (4) screening of chemotherapy drugs; (5) reduction of intracranial pressure; (6) relief of neurological dysfunction. 2. Factors related to surgical prognosis: (1) tumor grade; (2) age (≤65 years vs. >65 years); (3) preoperative neurological status (KPS ≥70 vs. <70); (4) extent of tumor resection (total vs. non-total resection); (5) site and number of lesions [2]; (6) primary or recurrence. (Level II evidence: Laws 2003; multiple consistent Level III evidence: Simpson 1993, Rostomily 1994, Lacroix 2001) 3. Surgical strategy: It is strongly recommended that for primary high-grade (WHO grade III-IV) or low-grade (WHO grade II) malignant gliomas confined to the lobes of the brain, the maximum extent of safe Removal of the tumor. Gliomas usually grow in an expansive infiltrative pattern, but are locally restricted by the cerebral sulcus and gyrus and tend to expand along the white matter fiber tracts. Based on the growth pattern and blood supply characteristics of glioma, it is recommended to use micro-neurosurgery technique to make anatomical resection along the white matter fiber bundle of tumor margin with the boundary of cerebral sulcus and cerebral gyrus to obtain maximum tumor resection with minimal tissue and neurological function damage and clear histopathological diagnosis. It is recommended that for (1) diffuse infiltrative growth in the dominant hemisphere, (2) lesions invading bilateral hemispheres, (3) elderly patients (>65 years old), (4) preoperative poor neurological status (KPS <70), (5) malignant glioma in deep intracerebral or brainstem sites, (6) gliomatosis, partial tumor resection, open biopsy or stereotactic (or under navigation) puncture biopsy may be used as appropriate. Partial tumor resection has a higher survival advantage than biopsy alone. Biopsy is primarily indicated for lesions adjacent to functional cortical areas or in deep locations that are not clinically resectable. Biopsy mainly includes stereotactic (or under navigation) biopsy and open surgical biopsy. Stereotactic (or guided) biopsy is suitable for lesions that are more deeply located, while open biopsy is suitable for lesions that are superficially located or close to the functional cortex. After minimizing the tumor volume, reducing the tumor cell load and clarifying the histopathological nature, individualized and standardized adjuvant radiotherapy is implemented. 4. Postoperative resection assessment: It is strongly recommended to review MRI in the early postoperative period (<72 hours) to assess the extent of glioma resection based on quantitative analysis of the volume of preoperative and postoperative imaging. T1WI-enhanced MRI of high-grade malignant glioma is currently recognized as the "gold standard" for diagnostic imaging; T2WI or FAIR sequence imaging of low-grade malignant glioma is recommended. In units where MRI review is not available, CT review is recommended in the early postoperative period (<72 hours). New techniques to assist surgical resection and improve surgical outcomes: New techniques in image-guided surgery can help achieve maximum safe resection of malignant gliomas. Recommended: conventional neuronavigation, functional neuronavigation, intraoperative neurophysiological monitoring techniques (e.g., functional cortical localization and subcortical stimulation of nerve conduction bundles), intraoperative MRI real-time imaging (intraoperative imaging) neuronavigation. May recommend: fluoroscopy-guided microsurgery, intraoperative ultrasound imaging for real-time localization. 6. Evidence supporting the recommendation (1) The extent of tumor resection is one of the independent prognostic factors for high-grade malignant glioma, and total tumor resection is strongly associated with postoperative recurrence interval and survival time. (Multiple consistent Level II evidence: Ammirati 1987, Albert 1994, Wirtz 2000, Laws 2003; Level III evidence Ammirati 1987, Simpson 1993, Lacroix 2001, Buckner 2003) (2) Current tendency is to believe that maximum safe tumor resection helps to prolong the recurrence interval of low-grade malignant gliomas (level II evidence: Berger 1994). Partial resection of low-grade malignant gliomas (WHO grade II) is associated with a 1.4-fold risk of case recurrence and a 4.9-fold risk of death compared with total resection (level II evidence: Claus 2005). However, studies on the correlation between total tumor resection and operative survival time have not been obtained with Level I evidence (Keles 2001). (3) The risk of death in cases of glioblastoma (GBM) with tumor remnants found on early postoperative MRI is 6.595 times higher than in cases without tumor remnants. (Level II evidence: Albert 1994) ⑷ Partial resection of GBM has a higher survival advantage than biopsy alone. (Level III evidence, Simpson 1993) (5) The diagnostic accuracy of biopsy is higher than that of imaging, but misdiagnosis rates still exist due to tumor heterogeneity and target area selection. A retrospective study showed lower postoperative complications with stereotactic biopsy compared to craniotomy (12.3% vs. 3.7%), but a misdiagnosis rate of 49% (Level III evidence, Jackson 2001). Another randomized controlled study of open surgical resection compared to stereotactic biopsy for HGG in the elderly (Level II evidence, Vuorinen 2003) showed that open surgical resection (including total and subtotal resection) resulted in 2.757 times greater median survival than stereotactic biopsy (95% CI 1.004C7.568, p = 0.049), but with limited overall benefit and there was no significant difference in the time to progression to progression between the two. Another study showed (Level III evidence, Hall 1998) that the disabling factors associated with biopsy were: basal ganglia injury, thalamic injury, diabetes mellitus and hyperglycemia on the day of surgery. The disability rate was 3.5% and the lethality rate was 0.7%, both associated with bleeding due to puncture. (6) Imaging total resection of malignant glioma helps improve the patient's postoperative neurological status and improves the quality of survival. (Level III evidence: Ammirati 1987, Sawaya 1998, Whittle 1998, Brown 2005) (7) High-grade malignant glioma up to 99% resection can reduce the tumor cell load from 109 to 107, and postoperative adjuvant radiotherapy can help prolong patient survival. (Level I evidence: Stewart 2002) (8) Through the study of early postoperative MRI of malignant glioma, it was shown that the peripheral circumferential enhancement of the operated area was mainly related to the following factors: (1) local blood-brain barrier disruption; (2) granulation tissue proliferation; and (3) overperfusion caused by vascular self-regulation dysfunction. Reviewing MRI within 72 hours after surgery can reduce the interference of the above factors and decrease the false-positive rate. About 80% of tumor recurrence foci originate from tumor remnants detected by early postoperative MRI. (Level II evidence: Albert 1994) (9) Neuronavigation helps to improve the rate of total surgical resection of gliomas (multiple consistent Level III evidence: Du 2003 et al). Functional neuronavigation improves the rate of total resection of malignant gliomas in the motor area, reduces postoperative disability, improves patients' long-term quality of life, and reduces the risk of postoperative death by 43.0% (Class II evidence: Wu 2007). Functional neuronavigation surgery is equally applicable to cortical language area and visual area glioma surgery. Conventional MRI reconstruction of the cranial structure model, fMRI-BOLD localization of the functional cortical areas, and DTI display of the subcortical nerve conduction bundles are used to precisely locate the adjacent neurological functional areas while defining the lesion boundaries, respectively. Intraoperative neurophysiological monitoring techniques are the standard technique for intraoperative localization of functional cerebral cortex and subcortical nerve conduction tracts in gliomas (Level II evidence: Keles 2004; multiple consistent Level III evidence: Berger 1992, Duffau 2003, Bello 2006 and 2007). Intraoperative neurophysiological monitoring techniques have been used to confirm the reliability of BOLD and DTI for functional cortical and subcortical conduction pathways, respectively (multiple consistent Level III evidence: Fandino 1999, Berman 2007, Bello 2008). The latest intraoperative MRI real-time image navigation techniques can increase the rate of total surgical resection of gliomas and improve clinical prognosis. Multiple consistent Level II (Wirtz 2000, Claus 2007) and Level III (Black 1999, Nimsky 2006, Muragaki 2006, Senft 2008) evidence of its effectiveness has also been obtained. Limitations of this paper 1. The grading of evidence and recommendations in this paper are based on the current published literature and data, and not all the current global relevant literature has been collected, so there may be selective bias. 2. Since each study has a different perspective of analysis, there are differences in the classification of evidence and recommendation stages of development, and the conclusions of this paper are for reference only.