Table 1.
Summary of Class of Evidence and Strength of Recommendation
| Statement | Class of Evidence | Level of Recommendation |
|---|---|---|
| Perioperative drugs management | ||
| Glioma patients who never suffered seizures should not be treated with primary prophylaxis with antiseizure medications (ASMs) [25–29] | I | A |
| Dexamethasone is considered the standard agent due to its high potency and relative lack of mineralocorticoid activity reduce the potential for fluid retention [30–32] | I | A |
| Anticoagulation with low molecular weight heparin or direct oral anticoagulants for established venous tromboembolism is recommended in patients with primary brain tumors [33] | II | B |
| Imaging | ||
| The standard protocol includes anatomical, two-dimensional T2-weighted and FLAIR sequences (slice thickness ≤ 4 mm), FLAIR sequences (three-dimensional FLAIR is suggested as an alternative to 2D FLAIR) and three-dimensional T1-weighted images acquired pre- and post-contrast administration [34–36] | II | C |
| An early postoperative MRI is strongly suggested and should be performed within 48 to 72 hours after surgery, including DWI sequences [37] | II | B |
|
Advanced techniques, such as diffusion MRI (dMRI), perfusion-weighted imaging (PWI), proton magnetic resonance spectroscopy (1HMRS) and positron emission tomography (PET) can provide a visual depiction and quantitative measurement of the pathophysiologic characteristics of the tumor [38, 39] PET-CT can provide information about biology, differential diagnosis, delineation of tumor extent for surgical or RT planning, which can be also usefull in post-treatment surveillance (progression vs pseudoprogression) [237] |
III | C |
| Surgery | ||
| The extent of surgical resection (EOR) is a strongest independent risk factor for both overall survival (OS) and tumor recurrence [40–43] | II | B |
| Intraoperative neurophysiological monitoring is associated with lower risk of permanent postoperative deficits and a higher EOR of tumors in eloquent areas [44, 45] | II | B |
| Cortico-subcortical mapping is the most sensitive and specific technique for the identification of critical cortical hubs and white matter bundles [46, 47] | III | C |
| Awake surgery can be considered an option, mainly in young patients with lesions in the dominant hemisphere involving language, motor and somato-sensory areas [47–50] | III | C |
| Intraoperative imaging | ||
| NN: neuro-navigation systems represent the most used intraoperative tool used by neurosurgeons during tumor excision. Based on preoperative imaging, and overlap with FMRI-DTI, neuro-navigation allows preoperative identification of eloquent regions and guides the surgeon during intraoperative mapping and tumor resection [51–56] | III | C |
| iCT: iCT helped to verify EOR and to identify and resect pathological tissue. iCT represents a feasible and effective alternative for intraoperative updates of the neuro-navigation system [11, 57] | III | C |
|
iUS: iUS is a real-time, accurate and inexpensive imaging method for optimizing the EOR in neurosurgical interventions Despite being an operator-dependent method, iUS is associated with a greater EOR and improved PFS and OS in glioma patients [58–60] |
III | C |
|
iMRI: iMRI was found to be associated with higher resection rates compared to the neuro-navigated procedures, Unfortunately, the high cost and the need for structural changes in the operating room have limited, to date, the spread of intraoperative MRI [59–64] |
III | C |
|
5-ALA: 5-ALA is a metabolic tracer that allows the intraoperative distinction of the boundaries between healthy tissue and tumor near the infiltration zones, thus guiding the glioma resection |
II | B |
| Fluorescence: sodium fluorescein (FLCN): The intraoperative guidance determined by FLCN allows to predict histopathological alterations both in areas with contrast enhancement and in the margins of infiltration of the cerebral parenchyma that do not present a neuroimaging contrast [60, 70, 73–76] | III | C |
| Intraoperative treatment options | ||
| In newly diagnosed HGGs, CWs implantations should not be considered as first-line therapeutic option [77–81] | II | B |
| Estimation of extent of tumor resection | ||
| The objective estimation of the extent of tumor resection is fundamental in planning postoperative adjuvant treatments, stratifying patients’ prognosis and monitoring tumor evolution over time in response to adjuvant treatments [37, 41, 43, 82, 83] | II | B |
| The volumetric analysis can be carried out by manual segmentation of the areas of interest or by using the so-called ellipsoid volume technique or software with automatic or manual segmentation [82, 84] | III | C |
| Stereotactic image-guided brain biopsy is the procedure of choice when an extensive surgical resection is not feasible, as in deep-seated or multifocal tumors, or if the patient has considerable comorbidities increasing the risk of perioperative morbidity or even mortality [85–87] | II | B |
| Surgery at tumor progression | ||
| The role of second surgery at recurrence is not definitively validated and should be evaluated on individual basis [88–96] | III | C |
| Surgery in elderly patients | ||
| Thorough evaluation and surgical selection of elderly glioma patients may lead to favorable survival benefit [97–99] | III | C |