Laser interstitial thermal therapy for deep-seated perivascular brain tumors is not associated with distal ischemia.

PURPOSE: Laser interstitial thermal therapy (LITT) is a minimally invasive cytoreductive treatment option for brain tumors with a risk of vascular injury from catheter placement or thermal energy. This may be of concern with deep-seated tumors that have surrounding end-artery perforators and critical microvasculature. The purpose of this study was to assess the risk of distal ischemia following LITT for deep-seated perivascular brain tumors. METHODS: A retrospective review of a multi-institution database was used to identify patients who underwent LITT between 2013 and 2022 for tumors located within the insula, thalamus, basal ganglia, and anterior perforated substance. Demographic, clinical and volumetric tumor characteristics were collected. The primary outcome was radiographic evidence of distal ischemia on post-ablation magnetic resonance imaging (MRI). RESULTS: 61 LITT ablations for deep-seated perivascular brain tumors were performed. Of the tumors treated, 24 (39%) were low-grade gliomas, 32 (52%) were high-grade gliomas, and 5 (8%) were metastatic. The principal location included 31 (51%) insular, 14 (23%) thalamic, 13 (21%) basal ganglia, and 3 (5%) anterior perforated substance tumors. The average tumor size was 19.6 cm3 with a mean ablation volume of 11.1 cm3. The median extent of ablation was 92% (IQR 30%, 100%). Two patients developed symptomatic intracerebral hemorrhage after LITT. No patient had radiographic evidence of distal ischemia on post-operative diffusion weighted imaging. CONCLUSION: We demonstrate that LITT for deep-seated perivascular brain tumors has minimal ischemic risks and is a feasible cytoreductive treatment option for otherwise difficult to access intracranial tumors.

COVID-19 in the hotspot of Metropolitan Detroit: A multi-faceted health system experience.

Health systems were abruptly plunged into a crisis as SARS-CoV-2 exploded into a pandemic in spring 2020. In March-April 2020, Metropolitan Detroit was a US "hotspot." As a large health system with five hospitals and two behavioural health inpatient facilities, a health insurance company, a medical group and physician network, and 41 ambulatory clinics normally hosting over 10,000 daily patient encounters, the Henry Ford Health System deployed numerous strategies in the management of this upheaval. As hospitals and Emergency Departments were inundated with COVID-19 patients, other services and activities needed to shut down as state-mandated policies were promulgated, new internal and external communication networks established, and management of employees and resources such as ventilators, ICU beds, personal protective equipment, and laboratory supplies became critical challenges. We describe herein the system-wide strategies implemented and lessons learned in the operation of a health system in the initial throes of a global pandemic.

Congress of neurological surgeons systematic review and evidence-based guidelines update on the role of chemotherapeutic management and antiangiogenic treatment of newly diagnosed glioblastoma in adults.

QUESTION: What is the role of temozolomide in the management of adult patients (aged 65 and under) with newly diagnosed glioblastoma? TARGET POPULATION: These recommendations apply to adult patients diagnosed with newly diagnosed glioblastoma. RECOMMENDATION: Level I: Concurrent and post-irradiation Temozolomide (TMZ) in combination with radiotherapy and post-radiotherapy as described by Stupp et al. is recommended to improve both PFS and OS in adult patients with newly diagnosed GBM. There is no evidence that alterations in the dosing regimen have additional beneficial effect. QUESTION: Is there benefit to adjuvant temozolomide treatment in elderly patients (> 65 years old?). TARGET POPULATION: These recommendations apply to adult patients diagnosed with newly diagnosed glioblastoma. RECOMMENDATION: Level III: Adjuvant TMZ treatment is suggested as a treatment option to improve PFS and OS in adult patients (over 70 years of age) with newly diagnosed GBM. QUESTION: What is the role of local regional chemotherapy with BCNU biodegradable polymeric wafers in adult patients with newly diagnosed glioblastoma? TARGET POPULATION: These recommendations apply to adult patients diagnosed with newly diagnosed glioblastoma. RECOMMENDATION: Level III: There is insufficient evidence for the use of BCNU wafers following resection in patients with newly diagnosed glioblastoma who undergo the Stupp protocol after surgery. Further studies of higher quality are suggested to understand the role of BCNU wafer and other locoregional therapy in the setting of Stupp Protocol. QUESTION: What is the role of bevacizumab in the adult patient with newly diagnosed glioblastoma? TARGET POPULATION: These recommendations apply to adult patients diagnosed with newly diagnosed glioblastoma. RECOMMENDATION: Level I: Bevacizumab in general is not recommended in the initial treatment of adult patients with newly diagnosed GBM. It continues to be strongly recommended that patients with newly diagnosed GBM be enrolled in properly designed clinical trials to assess the benefit of novel chemotherapeutic agents compared to standard therapy.

The impact of 5-aminolevulinic acid on extent of resection in newly diagnosed high grade gliomas: a systematic review and single institutional experience.

BACKGROUND: Glioma surgery at its nascency relied predominantly on visual and tactile feedback for the removal of grossly abnormal tissue. This technique has inherent limitations in delineating infiltrative tumor from normal brain, thus limiting the ability to achieve a gross total resection consistently. Since extent of resection (EOR) is consistently correlated with measures of survival, fluorescence-guided surgery shows promise in improving our ability to treat high-grade gliomas (HGG). 5-Aminolevulinic acid (5-ALA) is a prodrug preferentially metabolized by glioma cells that allows direct, real-time visualization of pathologic tissue through fluorescence under blue light. OBJECTIVE: To report the relationship between 5-ALA and EOR in newly diagnosed HGG. To report our institutional experience including nuances of workflow. METHODS: The authors performed a systematic review of the available literature between 1998 and 2018 to isolate studies addressing the impact of fluorescence-guided surgery with 5-ALA on the EOR in newly diagnosed HGG. Search strategy was in adherence to the preferred reporting items for systematic reviews and meta-analyses methodology. RESULTS: Out of 741 unique articles, eight fulfilled our strict inclusion criteria. Fluorescence-guided resection led to greater EOR in all studies, with six demonstrating statistical significance (p < 0.05). Two studies additionally demonstrated statistically significant increase in progression-free survival in the 5-ALA groups. CONCLUSIONS: 5-ALA has an unambiguously positive impact on improving EOR for newly diagnosed HGG. Since the nature of modern glioma surgery includes a complex arsenal of surgical adjuncts, 5-ALA is seldom examined in isolation and can be complemented by intraoperative MRI.

Clinical trial design for local therapies for brain metastases: a guideline by the Response Assessment in Neuro-Oncology Brain Metastases working group.

The goals of therapeutic and biomarker development form the foundation of clinical trial design, and change considerably from early-phase to late-phase trials. From these goals, decisions on specific clinical trial design elements, such as endpoint selection and statistical approaches, are formed. Whereas early-phase trials might focus on finding a therapeutic signal to make decisions on further development, late-phase trials focus on the confirmation of therapeutic impact by considering clinically meaningful endpoints. In this guideline from the Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) working group, we highlight issues related to, and provide recommendations for, the design of clinical trials on local therapies for CNS metastases from solid tumours. We discuss endpoint selection criteria, the analysis appropriate for early-phase and late-phase trials, the association between tumour-specific and clinically meaningful endpoints, and possible issues related to the estimation of local control in the context of competing risks. In light of these discussions, we make specific recommendations on the clinical trial design of local therapies for brain metastases.

The safety of magnetic resonance imaging-guided laser interstitial thermal therapy for cerebral radiation necrosis.

Cerebral radiation necrosis (CRN) is a known complication of radiation therapy. Treatment options are limited and include steroids, bevacizumab, and surgery. This study seeks to determine the safety of laser interstitial thermal therapy (LITT) for CRN and identify the pattern of post-ablation volume change over time. Patients undergoing LITT for tumor treatment at Henry Ford Hospital between November 2013 and January 2016 with biopsy-confirmed CRN were prospectively collected and retrospectively reviewed with attention to ablation volume, survival, demographic data, steroid dose, and complications. Imaging occurred at set intervals beginning pre-ablation. Ten patients with 11 ablations were evaluated. Four patients had a primary diagnosis of high-grade glioma, while six had metastatic lesions. An average of 86% of CRN volume was ablated. Ablation volume increased to 430% of initial CRN volume at 1-2 weeks before decreasing to 69% after 6 months. No patient had a decline in baseline neurological examination while in the hospital. Four patients developed delayed neurological deficits likely due to post-operative edema, of which three improved back to baseline. The 6-month survival was 77.8% and the 1-year survival was 64.8% based on Kaplan-Meier curve estimates. In this study, LITT was a relatively safe treatment for CRN, providing both a diagnostic and therapeutic solution for refractory patients. Significant increase in ablation volume was noted at 1-2 months, gradually decreasing in size to less than the original volume by 6 months. Further studies are needed to better define the role of LITT in the treatment of CRN.

Shining light on neurosurgery diagnostics using Raman spectroscopy.

Surgical excision of brain tumors provides a means of cytoreduction and diagnosis while minimizing neurologic deficit and improving overall survival. Despite advances in functional and three-dimensional stereotactic navigation and intraoperative magnetic resonance imaging, delineating tissue in real time with physiological confirmation is challenging. Raman spectroscopy is a promising investigative and diagnostic tool for neurosurgery, which provides rapid, non-destructive molecular characterization in vivo or in vitro for biopsy, margin assessment, or laboratory uses. The Raman Effect occurs when light temporarily changes a bond's polarizability, causing change in the vibrational frequency, with a corresponding change in energy/wavelength of the scattered photon. The recorded inelastic scattering results in a "fingerprint" or Raman spectrum of the constituent under investigation. The amount, location, and intensity of peaks in the fingerprint vary based on the amount of vibrational bonds in a molecule and their ensemble interactions with each other. Distinct differences between various pathologic conditions are shown as different intensities of the same peak, or shifting of a peak based on the binding conformation. Raman spectroscopy has potential for integration into clinical practice, particularly in distinguishing normal and diseased tissue as an adjunct to standard pathologic diagnosis. Further, development of fiber-optic Raman probes that fit through the instrument port of a standard endoscope now allows researchers and clinicians to utilize spectroscopic information for evaluation of in vivo tissue. This review highlights the need for such an instrument, summarizes neurosurgical Raman work performed to date, and discusses the future applications of neurosurgical Raman spectroscopy.

Response assessment criteria for brain metastases: proposal from the RANO group.

CNS metastases are the most common cause of malignant brain tumours in adults. Historically, patients with brain metastases have been excluded from most clinical trials, but their inclusion is now becoming more common. The medical literature is difficult to interpret because of substantial variation in the response and progression criteria used across clinical trials. The Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) working group is an international, multidisciplinary effort to develop standard response and progression criteria for use in clinical trials of treatment for brain metastases. Previous efforts have focused on aspects of trial design, such as patient population, variations in existing response and progression criteria, and challenges when incorporating neurological, neuro-cognitive, and quality-of-life endpoints into trials of patients with brain metastases. Here, we present our recommendations for standard response and progression criteria for the assessment of brain metastases in clinical trials. The proposed criteria will hopefully facilitate the development of novel approaches to this difficult problem by providing more uniformity in the assessment of CNS metastases across trials.

The role of initial chemotherapy for the treatment of adults with diffuse low grade glioma : A systematic review and evidence-based clinical practice guideline.

TARGET POPULATION: Adult patients (older than 18 years of age) with newly diagnosed World Health Organization (WHO) Grade II gliomas (Oligodendroglioma, astrocytoma, mixed oligoastrocytoma). QUESTION: Is there a role for chemotherapy as adjuvant therapy of choice in treatment of patients with newly diagnosed low-grade gliomas? LEVEL III: Chemotherapy is recommended as a treatment option to postpone the use of radiotherapy, to slow tumor growth and to improve progression free survival (PFS), overall survival (OS) and clinical symptoms in adult patients with newly diagnosed LGG. QUESTION: Who are the patients with newly diagnosed LGG that would benefit the most from chemotherapy? LEVEL III: Chemotherapy is recommended as an optional component alone or in combination with radiation as the initial adjuvant therapy for all patients who cannot undergo gross total resection (GTR) of a newly diagnosed LGG. Patient with residual tumor >1 cm on post-operative MRI, presenting diameter of >4 cm or older than 40 years of age should be considered for adjuvant therapy as well. QUESTION: Are there tumor markers that can predict which patients can benefit the most from initial treatment with chemotherapy? LEVEL III: The addition of chemotherapy to standard RT is recommended in LGG patients that carry IDH mutation. In addition, temozolomide (TMZ) is recommended as a treatment option to slow tumor growth in patients who harbor the 1p/19q co-deletion. QUESTION: How soon should the chemotherapy be started once the diagnosis of LGG is confirmed? RECOMMENDATION: There is insufficient evidence to make a definitive recommendation on the timing of starting chemotherapy after surgical/pathological diagnosis of LGG has been made. However, using the 12 weeks mark as the latest timeframe to start adjuvant chemotherapy is suggested. It is recommended that patients be enrolled in properly designed clinical trials to assess the timing of chemotherapy initiation once diagnosis is confirmed for this target population. QUESTION: What chemotherapeutic agents should be used for treatment of newly diagnosed LGG? RECOMMENDATION: There is insufficient evidence to make a recommendation of one particular regimen. Enrollment of subjects in properly designed trials comparing the efficacy of these or other agents is recommended so as to determine which of these regimens is superior. QUESTION: What is the optimal duration and dosing of chemotherapy as initial treatment for LGG? RECOMMENDATION: Insufficient evidence exists regarding the duration of any specific cytotoxic drug regimen for treatment of newly diagnosed LGG. Enrollment of subjects in properly designed clinical investigations assessing the optimal duration of this therapy is recommended. QUESTION: Should chemotherapy be given alone or in conjunction with RT as initial therapy for LGG? RECOMMENDATION: Insufficient evidence exists to make recommendations in this regard. Hence, enrollment of patients in properly designed clinical trials assessing the difference between chemotherapy alone, RT alone or a combination of them is recommended. QUESTION: Should chemotherapy be given in addition to other type of adjuvant therapy to patients with newly diagnosed LGG? RECOMMENDATION: Level II: It is recommended that chemotherapy be added to the RT in patients with unfavorable LGG to improve their progression free survival.

The role of radiotherapy in the management of patients with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline.

QUESTIONS: (1) What is the optimal role of external beam radiotherapy in the management of adult patients with newly diagnosed low-grade glioma (LGG) in terms of improving outcome (i.e., survival, complications, seizure control or other reported outcomes of interest)? (2) Which radiation strategies (dose, timing, fractionation, stereotactic radiation, brachytherapy, chemotherapy) improve outcomes compared to standard external beam radiation therapy in the initial management of low grade gliomas in adults? (3) Do specific factors (e.g., age, volume, extent of resection, genetic subtype) identify subgroups with better outcomes following radiation therapy than the general population of adults with newly diagnosed low-grade gliomas? TARGET POPULATION: These recommendations apply to adults with newly diagnosed diffuse LGG. RECOMMENDATIONS: OUTCOMES IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA TREATED WITH RADIOTHERAPY: Level I Radiotherapy is recommended in the management of newly diagnosed low-grade glioma in adults to prolong progression free survival, irrespective of extent of resection. Level II Radiotherapy is recommended in the management of newly diagnosed low grade glioma in adults as an equivalent alternative to observation in preserving cognitive function, irrespective of extent of resection. Level III Radiotherapy is recommended in the management of newly diagnosed low grade glioma in adults to improve seizure control in patients with epilepsy and subtotal resection. Level III Radiotherapy is recommended in the management of newly diagnosed low-grade glioma in adults to prolong overall survival in patients with subtotal resection. Level III Consideration of the risk of radiation induced morbidity, including cognitive decline, imaging abnormalities, metabolic dysfunction and malignant transformation, is recommended when the delivery of radiotherapy is selected in the management of newly diagnosed low-grade glioma in adults. STRATEGIES OF RADIOTHERAPY IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA: Level I Lower dose radiotherapy is recommended as an equivalent alternative to higher dose immediate postoperative radiotherapy (45-50.4 vs. 59.4-64.8 Gy) in the management of newly diagnosed low-grade glioma in adults with reduced toxicity. Level III Delaying radiotherapy until recurrence or progression is recommended as an equivalent alternative to immediate postoperative radiotherapy in the management of newly diagnosed low-grade glioma in adults but may result in shorter time to progression. Level III The addition of chemotherapy to radiotherapy is not recommended over whole brain radiotherapy alone in the management of low-grade glioma, as it provides no additional survival benefit. Level III Limited-field radiotherapy is recommended over whole brain radiotherapy in the management of low-grade glioma. Level III Either stereotactic radiosurgery or brachytherapy are recommended as acceptable alternatives to external radiotherapy in selected patients. PROGNOSTIC FACTORS IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA TREATED WITH RADIOTHERAPY: Level II It is recommended that age greater than 40 years, astrocytic pathology, diameter greater than 6 cm, tumor crossing the midline and preoperative neurological deficit be considered as negative prognostic indicators when predicting overall survival in adult low grade glioma patients treated with radiotherapy. Level II It is recommended that smaller tumor size, extent of surgical resection and higher mini-mental status exam be considered as positive prognostic indicators when predicting overall survival and progression free survival in patients in adult low grade glioma patients treated with radiotherapy. Level III It is recommended that seizures at presentation, presence of oligodendroglial histological component and 1p19q deletion (along with additional relevant factors-see Table 1) be considered as positive prognostic indicators when predicting response to radiotherapy in adults with low grade gliomas. Level III It is recommended that increasing age, decreasing performance status, decreasing cognition, presence of astrocytic histological component (along with additional relevant factors (see Tables 1, 2) be considered as negative prognostic indicators when predicting response to radiotherapy.

The role of biopsy in the management of patients with presumed diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline.

QUESTION: What is the optimal role of biopsy in the initial management of presumptive low-grade glioma in adults? TARGET POPULATION: Adult patients with imaging suggestive of a low-grade glioma. LEVEL III: Stereotactic biopsy is recommended when definitive surgical resection is limited by lesions that are deep-seated, not resectable, and/or located within eloquent cortex, or in patients unable to undergo craniotomy due to medical co-morbidities to obtain the critical tissue diagnosis needed for targeted treatment planning for patients with low-grade gliomas. QUESTION: What is the best technique for brain biopsy? TARGET POPULATION: Adult patients with imaging suggestive of a low-grade glioma. LEVEL III: Frameless and frame-based stereotactic brain biopsy for low-grade gliomas are recommended based on clinical circumstances as they provide similar diagnostic yield, diagnostic accuracy, morbidity, and mortality. It is recommended the surgeon consider advanced imaging techniques (e.g., perfusion, spectroscopy, metabolic studies) to target specific regions of interest to potentially improve diagnostic accuracy.

The role of emerging therapy in the management of patients with diffuse low grade glioma.

QUESTION: What is the role of immunotherapy/tumor vaccines in the treatment of low grade gliomas? TARGET POPULATION: Adult patients with newly diagnosed WHO grade 2 astrocytoma, oligo-astroctyoma, or oligodendroglioma. RECOMMENDATIONS: There is no evidence to support a recommendation in regards to the efficacy of immunotherapy or tumor vaccines for the treatment of low grade gliomas. It is recommended that patients be enrolled in properly designed clinical trials to assess immunotherapies and tumor vaccines for low grade gliomas. QUESTION: What is the role of nutrition in the treatment of low grade gliomas? TARGET POPULATION: Adult patients with newly diagnosed WHO grade 2 astrocytoma, oligo-astroctyoma, or oligodendroglioma. RECOMMENDATIONS: There was no evidence to support a recommendation in regard to the efficacy of nutritional therapy for the treatment of low grade gliomas. It is recommended that patients be enrolled in properly designed clinical trials to assess the efficacy of nutrition for this target population. QUESTION: Is there a role for alternative or targeted therapies in the treatment of low grade gliomas? TARGET POPULATION: Adult patients with newly diagnosed WHO grade 2 astrocytoma, oligo-astroctyoma, or oligodendroglioma. RECOMMENDATION: There was no evidence to support a recommendation in regard to the efficacy of targeted or alternative agents for the treatment of low grade gliomas. It is recommended that patients be enrolled in properly designed clinical trials to assess alternative and targeted therapies for this target population.

The role of imaging in the management of adults with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline.

QUESTION: What is the optimal imaging technique to be used in the diagnosis of a suspected low grade glioma, specifically: which anatomic imaging sequences are critical for most accurately identifying or diagnosing a low grade glioma (LGG) and do non-anatomic imaging methods and/or sequences add to the diagnostic specificity of suspected low grade gliomas? TARGET POPULATION: These recommendations apply to adults with a newly diagnosed lesion with a suspected or histopathologically proven LGG. LEVEL II: In patients with a suspected brain tumor, the minimum magnetic resonance imaging (MRI) exam should be an anatomic exam with both T2 weighted and pre- and post-gadolinium contrast enhanced T1 weighted imaging. CRITICAL IMAGING FOR THE IDENTIFICATION AND DIAGNOSIS OF LOW GRADE GLIOMA: LEVEL II: In patients with a suspected brain tumor, anatomic imaging sequences should include T1 and T2 weighted and Fluid Attenuation Inversion Recovery (FLAIR) MR sequences and will include T1 weighted imaging after the administration of gadolinium based contrast. Computed tomography (CT) can provide additional information regarding calcification or hemorrhage, which may narrow the differential diagnosis. At a minimum, these anatomic sequences can help identify a lesion as well as its location, and potential for surgical intervention. IMPROVEMENT OF DIAGNOSTIC SPECIFICITY WITH THE ADDITION OF NON-ANATOMIC (PHYSIOLOGIC AND ADVANCED IMAGING) TO ANATOMIC IMAGING: LEVEL II: Class II evidence from multiple studies and a significant number of Class III series support the addition of diffusion and perfusion weighted MR imaging in the assessment of suspected LGGs, for the purposes of discriminating the potential for tumor subtypes and identification of suspicion of higher grade diagnoses. LEVEL III: Multiple series offer Class III evidence to support the potential for magnetic resonance spectroscopy (MRS) and nuclear medicine methods including positron emission tomography and single-photon emission computed tomography imaging to offer additional diagnostic specificity although these are less well defined and their roles in clinical practice are still being defined. QUESTION: Which imaging sequences or parameters best predict the biological behavior or prognosis for patients with LGG? TARGET POPULATION: These recommendations apply to adults with a newly diagnosed lesion with a suspected or histopathologically proven LGG. RECOMMENDATION: Anatomic and advanced imaging methods and prognostic stratification LEVEL III: Multiple series suggest a role for anatomic and advanced sequences to suggest prognostic stratification among low grade gliomas. Perfusion weighted imaging, particularly when obtained as a part of diagnostic evaluation (as recommended above) can play a role in consideration of prognosis. Other imaging sequences remain investigational in terms of their role in consideration of tumor prognosis as there is insufficient evidence to support more formal recommendations as to their use at this time. QUESTION: What is the optimal imaging technique to be used in the follow-up of a suspected (or biopsy proven) LGG? TARGET POPULATION: This recommendation applies to adults with a newly diagnosed low grade glioma. LEVEL II: In patients with a diagnosis of LGG, anatomic imaging sequences should include T2/FLAIR MR sequences and T1 weighted imaging before and after the administration of gadolinium based contrast. Serial imaging should be performed to identify new areas of contrast enhancement or significant change in tumor size, which may signify transformation to a higher grade. LEVEL III: Advanced imaging utility may depend on tumor subtype. Multicenter clinical trials with larger cohorts are needed. For astrocytic tumors, baseline and longitudinal elevations in tumor perfusion as assessed by dynamic susceptibility contrast perfusion MRI are associated with shorter time to tumor progression, but can be difficult to standardize in clinical practice. For oligodendrogliomas and mixed gliomas, MRS may be helpful for identification of progression.

The role of surgery in the management of patients with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline.

QUESTION: Should patients with imaging suggestive of low grade glioma (LGG) undergo observation versus treatment involving a surgical procedure? TARGET POPULATION: These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma). RECOMMENDATIONS: Surgical resection is recommended over observation to improve overall survival for patients with diffuse low-grade glioma (Level III) although observation has no negative impact on cognitive performance and quality of life (Level II). QUESTION: What is the impact of extent of resection on progression free survival (PFS) or overall survival (OS) in LGG patients? TARGET POPULATION: These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma). RECOMMENDATIONS: IMPACT OF EXTENT OF RESECTION ON PFS: LEVEL II: It is recommended that GTR or STR be accomplished instead of biopsy alone when safe and feasible so as to decrease the frequency of tumor progression recognizing that the rate of progression after GTR is fairly high. LEVEL III: Greater extent of resection can improve OS in LGG patients. QUESTION: What tools are available to increase extent of resection in LGG patients? TARGET POPULATION: These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma). RECOMMENDATIONS: INTRAOPERATIVE MRI DURING SURGERY: LEVEL III: The use of intraoperative MRI should be considered as a method of increasing the extent of resection of LGGs. QUESTION: What is the impact of surgical resection on seizure control and accuracy of pathology in low grade glioma patients? TARGET POPULATION: These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma). RECOMMENDATIONS: SURGICAL RESECTION AND SEIZURE CONTROL: LEVEL III: After taking into account the patient's clinical status and tumor location, gross total resection is recommended for patients with diffuse LGG as a way to achieve more favorable seizure control. LEVEL III: Taking into account the patient's clinical status and tumor location, surgical resection should be carried out to maximize the chance of accurate diagnosis. QUESTION: What tools can improve the safety of surgery for LGGs in eloquent locations? TARGET POPULATION: These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma). RECOMMENDATIONS: PREOPERATIVE IMAGING: LEVEL III: It is recommended that preoperative functional MRI and diffusion tensor imaging be utilized in the appropriate clinical setting to improve functional outcome after surgery for LGG. LEVEL III: Intraoperative mapping is recommended for patients with diffuse LGGs in eloquent locations compared to patients with non-eloquently located diffuse LGGs as a way of preserving function.

Identification of regions of normal grey matter and white matter from pathologic glioblastoma and necrosis in frozen sections using Raman imaging.

In neurosurgical applications, a tool capable of distinguishing grey matter, white matter, and areas of tumor and/or necrosis in near-real time could greatly aid in tumor resection decision making. Raman spectroscopy is a non-destructive spectroscopic technique which provides molecular information about the tissue under examination based on the vibrational properties of the constituent molecules. With careful measurement and data processing, a spatial step and repeat acquisition of Raman spectra can be used to create Raman images. Forty frozen brain tissue sections were imaged in their entirety using a 300-µm-square measurement grid, and two or more regions of interest within each tissue were also imaged using a 25 µm-square step size. Molecular correlates for histologic features of interest were identified within the Raman spectra, and novel imaging algorithms were developed to compare molecular features across multiple tissues. In previous work, the relative concentration of individual biomolecules was imaged. Here, the relative concentrations of 1004, 1300:1344, and 1660 cm(-1), which correspond primarily to protein and lipid content, were simultaneously imaged across all tissues. This provided simple interpretation of boundaries between grey matter, white matter, and diseased tissue, and corresponded with findings from adjacent hematoxylin and eosin-stained sections. This novel, yet simple, multi-channel imaging technique allows clinically-relevant resolution with straightforward molecular interpretation of Raman images not possible by imaging any single peak. This method can be applied to either surgical or laboratory tools for rapid, non-destructive imaging of grey and white matter.

The role of neuropathology in the management of patients with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline.

TARGET POPULATION: Adult patients (age ≥18 years) who have suspected low-grade diffuse glioma. QUESTION: What are the optimal neuropathological techniques to diagnose low-grade diffuse glioma in the adult? RECOMMENDATION: LEVEL I: Histopathological analysis of a representative surgical sample of the lesion should be used to provide the diagnosis of low-grade diffuse glioma. LEVEL III: Both frozen section and cytopathologic/smear evaluation should be used to aid the intra-operative assessment of low-grade diffuse glioma diagnosis. A resection specimen is preferred over a biopsy specimen, to minimize the potential for sampling error issues. TARGET POPULATION: Patients with histologically-proven WHO grade II diffuse glioma. QUESTION: In adult patients (age ≥18 years) with histologically-proven WHO grade II diffuse glioma, is testing for IDH1 mutation (R132H and/or others) warranted? If so, is there a preferred method? LEVEL II: IDH gene mutation assessment, via IDH1 R132H antibody and/or IDH1/2 mutation hotspot sequencing, is highly-specific for low-grade diffuse glioma, and is recommended as an additional test for classification and prognosis. TARGET POPULATION: Patients with histologically-proven WHO grade II diffuse glioma. QUESTION: In adult patients (age ≥18 years) with histologically-proven WHO grade II diffuse glioma, is testing for 1p/19q loss warranted? If so, is there a preferred method? LEVEL III: 1p/19q loss-of-heterozygosity testing, by FISH, array-CGH or PCR, is recommended as an additional test in oligodendroglial cases for prognosis and potential treatment planning. TARGET POPULATION: Patients with histologically-proven WHO grade II diffuse glioma. QUESTION: In adult patients (age ≥18 years) with histologically-proven WHO grade II diffuse glioma, is MGMT promoter methylation testing warranted? If so, is there a preferred method? RECOMMENDATION: There is insufficient evidence to recommend methyl-guanine methyl-transferase (MGMT) promoter methylation testing as a routine for low-grade diffuse gliomas. It is recommended that patients be enrolled in properly designed clinical trials to assess the value of this and related markers for this target population. TARGET POPULATION: Patients with histologically-proven WHO grade II diffuse glioma. QUESTION: In adult patients (age ≥18 years) with histologically-proven WHO grade II diffuse glioma, is Ki-67/MIB1 immunohistochemistry warranted? If so, is there a preferred method to quantitate results? LEVEL III: Ki67/MIB1 immunohistochemistry is recommended as an option for prognostic assessment.

Management of patients with recurrence of diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline.

TARGET POPULATION: These recommendations apply to adult patients with recurrent low-grade glioma (LGG) with initial pathologic diagnosis of a WHO grade II infiltrative glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma). QUESTION: Do pathologic and molecular characteristics predict outcome/malignant transformation at recurrence? RECOMMENDATIONS: IDH STATUS AND RECURRENCE: (Level III) IDH mutation status should be determined as LGGs with IDH mutations have a shortened time to recurrence. It is unclear whether knowledge of IDH mutation status provides benefit in predicting time to progression or overall survival. TP53 STATUS AND RECURRENCE: (Level III) TP53 mutations occur early in LGG pathogenesis, remain stable, and are not recommended as a marker of predisposition to malignant transformation at recurrence or other measures of prognosis. MGMT STATUS AND RECURRENCE: (Level III) Assessment of MGMT status is recommended as an adjunct to assessing prognosis as LGGs with MGMT promoter methylation are associated with shorter PFS (in the absence of TMZ) and longer post-recurrence survival (in the presence of TMZ), ultimately producing similar overall survival to LGGs without MGMT methylation. The available retrospective reports are conflicting and comparisons between reports are limited CDK2NA STATUS AND RECURRENCE: (Level III) Assessment of CDK2NA status is recommended when possible as the loss of expression of the CDK2NA via either methylation or loss of chromosome 9p is associated with malignant progression of LGGs. PROLIFERATIVE INDEX AND RECURRENCE: (Level III) It is recommended that proliferative indices (MIB-1 or BUdR) be measured in LGGs as higher proliferation indices are associated with increased likelihood of recurrence and shorter progression free and overall survival. 1P/19Q STATUS AND RECURRENCE: There is insufficient evidence to make any recommendations. QUESTION: What role does chemotherapy have in LGG recurrence? RECOMMENDATIONS: TEMOZOLOMIDE AND RECURRENCE: (Level III) Temozolomide is recommended in the therapy of recurrent LGG as it may improve clinical symptoms. Oligodendrogliomas and tumors with 1p/19q co-deletion may derive the most benefit. PCV AND RECURRENCE: (Level III) PCV is recommended in the therapy of LGG at recurrence as it may improve clinical symptoms with the strongest evidence being for oligodendrogliomas. CARBOPLATIN AND RECURRENCE : (Level III) Carboplatin is not recommended as there is no significant benefit from carboplatin as single agent therapy for recurrent LGGs. OTHER TREATMENTS (NITROSUREAS, HYDROXYUREA/IMANITIB, IRINOTECAN, PACLITAXEL) AND RECURRENCE: There is insufficient evidence to make any recommendations. It is recommended that individuals with recurrent LGGs be enrolled in a properly designed clinical trial to assess these chemotherapeutic agents. QUESTION: What role does radiation have in LGG recurrence? RECOMMENDATIONS: RADIATION AT RECURRENCE WITH NO PREVIOUS IRRADIATION: (Level III) Radiation is recommended at recurrence if there was no previous radiation treatment. RE-IRRADIATION AT RECURRENCE: (Level III) It is recommended that re-irradiation be considered in the setting of LGG recurrence as it may provide benefit in disease control. SURGERY AT RECURRENCE: There is insufficient evidence to make any specific recommendations. It is recommended that individuals with recurrent LGGs be enrolled in a properly designed clinical trial to assess the role of surgery at recurrence.

Characteristics of a novel treatment system for linear accelerator-based stereotactic radiosurgery.

The purpose of this study is to characterize the dosimetric properties and accuracy of a novel treatment platform (Edge radiosurgery system) for localizing and treating patients with frameless, image-guided stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). Initial measurements of various components of the system, such as a comprehensive assessment of the dosimetric properties of the flattening filter-free (FFF) beams for both high definition (HD120) MLC and conical cone-based treatment, positioning accuracy and beam attenuation of a six degree of freedom (6DoF) couch, treatment head leakage test, and integrated end-to-end accuracy tests, have been performed. The end-to-end test of the system was performed by CT imaging a phantom and registering hidden targets on the treatment couch to determine the localization accuracy of the optical surface monitoring system (OSMS), cone-beam CT (CBCT), and MV imaging systems, as well as the radiation isocenter targeting accuracy. The deviations between the percent depth-dose curves acquired on the new linac-based system (Edge), and the previously published machine with FFF beams (TrueBeam) beyond D(max) were within 1.0% for both energies. The maximum deviation of output factors between the Edge and TrueBeam was 1.6%. The optimized dosimetric leaf gap values, which were fitted using Eclipse dose calculations and measurements based on representative spine radiosurgery plans, were 0.700 mm and 1.000 mm, respectively. For the conical cones, 6X FFF has sharper penumbra ranging from 1.2-1.8 mm (80%-20%) and 1.9-3.8 mm (90%-10%) relative to 10X FFF, which has 1.2-2.2mm and 2.3-5.1mm, respectively. The relative attenuation measurements of the couch for PA, PA (rails-in), oblique, oblique (rails-out), oblique (rails-in) were: -2.0%, -2.5%, -15.6%, -2.5%, -5.0% for 6X FFF and -1.4%, -1.5%, -12.2%, -2.5%, -5.0% for 10X FFF, respectively, with a slight decrease in attenuation versus field size. The systematic deviation between the OSMS and CBCT was -0.4 ± 0.2 mm, 0.1± 0.3mm, and 0.0 ± 0.1 mm in the vertical, longitudinal, and lateral directions. The mean values and standard deviations of the average deviation and maximum deviation of the daily Winston-Lutz tests over three months are 0.20 ± 0.03 mm and 0.66 ± 0.18 mm, respectively. Initial testing of this novel system demonstrates the technology to be highly accurate and suitable for frameless, linac-based SRS and SBRT treatment.

The role of cytoreductive surgery in the management of progressive glioblastoma : a systematic review and evidence-based clinical practice guideline.

QUESTION: Should patients with previously diagnosed malignant glioma who are suspected of experiencing progression of the neoplasm process undergo repeat open surgical resection? TARGET POPULATION: These recommendations apply to adults with previously diagnosed malignant glioma who are suspected of experiencing progression of the neoplastic process and are amenable to surgical resection. RECOMMENDATIONS LEVEL II: Repeat cytoreductive surgery is recommended in symptomatic patients with locally recurrent or progressive malignant glioma. The median survival in these patient diagnosed with glioblastoma is expected to range from 6 to 17 months following a second procedure. It is recommended that the following preoperative factors be considered when evaluating a patient for repeat operation: location of recurrence in eloquent/critical brain regions, Karnofsky Performance Status and tumor volume.