Current Trends in Neurosurgical Management of Adult Diffuse Low-Grade Gliomas in Canada.

There is considerable variability in the management of diffuse low-grade gliomas (LGGs). To characterize treatment paradigms, a survey of Canadian neurosurgeons was performed with forty neurosurgeons responding. Their responses show that the management of patients with LGGs has evolved in the past decade and findings from the RTOG9802 trial have been integrated into the practice of Canadian neurosurgeons. Most respondents stated that the patient selection and treatment strategy advocated by the RTOG9802 trial needs further evaluation. Overall, there is a trend toward more aggressive surgical resections, and future investigations will have to more accurately stratify patient risk profiles.

Investigating Programmed Cell Death and Tumor Invasion in a Three-Dimensional (3D) Microfluidic Model of Glioblastoma.

Glioblastoma multiforme (GBM) is a rapidly progressive and deadly form of brain tumor with a median survival rate of ~15 months. GBMs are hard to treat and significantly affect the patient's physical and cognitive abilities and quality of life. Temozolomide (TMZ)-an alkylating agent that causes DNA damage-is the only chemotherapy choice for the treatment of GBM. However, TMZ also induces autophagy and causes tumor cell resistance and thus fails to improve the survival rate among patients. Here, we studied the drug-induced programmed cell death and invasion inhibition capacity of TMZ and a mevalonate cascade inhibitor, simvastatin (Simva), in a three-dimensional (3D) microfluidic model of GBM. We elucidate the role of autophagy in apoptotic cell death by comparing apoptosis in autophagy knockdown cells (Atg7 KD) against their scrambled counterparts. Our results show that the cells were significantly less sensitive to drugs in the 3D model as compared to monolayer culture systems. An immunofluorescence analysis confirmed that apoptosis is the mechanism of cell death in TMZ- and Simva-treated glioma cells. However, the induction of apoptosis in the 3D model is significantly lower than in monolayer cultures. We have also shown that autophagy inhibition (Atg7 KD) did not change TMZ and Simva-induced apoptosis in the 3D microfluidic model. Overall, for the first time in this study we have established the simultaneous detection of drug induced apoptosis and autophagy in a 3D microfluidic model of GBM. Our study presents a potential ex vivo platform for developing novel therapeutic strategies tailored toward disrupting key molecular pathways involved in programmed cell death and tumor invasion in glioblastoma.

Artificial intelligence in glioma imaging: challenges and advances.

Primary brain tumors including gliomas continue to pose significant management challenges to clinicians. While the presentation, the pathology, and the clinical course of these lesions are variable, the initial investigations are usually similar. Patients who are suspected to have a brain tumor will be assessed with computed tomography (CT) and magnetic resonance imaging (MRI). The imaging findings are used by neurosurgeons to determine the feasibility of surgical resection and plan such an undertaking. Imaging studies are also an indispensable tool in tracking tumor progression or its response to treatment. As these imaging studies are non-invasive, relatively cheap and accessible to patients, there have been many efforts over the past two decades to increase the amount of clinically-relevant information that can be extracted from brain imaging. Most recently, artificial intelligence (AI) techniques have been employed to segment and characterize brain tumors, as well as to detect progression or treatment-response. However, the clinical utility of such endeavours remains limited due to challenges in data collection and annotation, model training, and the reliability of AI-generated information. We provide a review of recent advances in addressing the above challenges. First, to overcome the challenge of data paucity, different image imputation and synthesis techniques along with annotation collection efforts are summarized. Next, various training strategies are presented to meet multiple desiderata, such as model performance, generalization ability, data privacy protection, and learning with sparse annotations. Finally, standardized performance evaluation and model interpretability methods have been reviewed. We believe that these technical approaches will facilitate the development of a fully-functional AI tool in the clinical care of patients with gliomas.

Laser Ablation of Abnormal Neurological Tissue Using Robotic Neuroblate System (LAANTERN): Procedural Safety and Hospitalization.

BACKGROUND: Stereotactic laser ablation (SLA) has demonstrated potential utility for a spectrum of difficult to treat neurosurgical pathologies in multiple small and/or retrospective single-institutional series. Here, we present the safety profile of SLA of intracranial lesions from the Laser Ablation of Abnormal Neurological Tissue using Robotic NeuroBlate System (LAANTERN; Monteris Medical) multi-institutional, international prospective observational registry. OBJECTIVE: To determine the procedural safety of SLA for intracranial lesions. METHODS: Prospective procedural safety and hospitalization data from the first 100 treated LAANTERN patients was collected and analyzed. RESULTS: Mean age and baseline Karnofsky Performance Status (KPS) were 51(± 17) yr and 83(± 15), respectively. In total, 81.2% of patients had undergone prior surgical or radiation treatment. Most patients had a single lesion (79%) ablated through 1 burr hole (1.2 ± 0.7 per patient), immediately following a lesion biopsy. In total, >90% of the lesion was ablated in 72% of treated lesions. Average total procedural time was 188.2 ± 69.6 min, and average blood loss was 17.7 ± 55.6 ccs. The average length of intensive care unit (ICU) and hospital stays before discharge were 38.1 ± 62.7 h and 61.1 ± 87.2 h, respectively. There were 5 adverse events (AEs) attributable to SLA (5/100; 5%). After the procedure, 84.8% of patients were discharged home. There was 1 mortality within 30 d of the procedure (1/100; 1%), which was not attributable to SLA. CONCLUSION: SLA is a safe, minimally invasive procedure with favorable postprocedural ICU and hospital utilization profiles.

The pivotal role of sampling recurrent tumors in the precision care of patients with tumors of the central nervous system.

Effective management of brain and spine tumors relies on a multidisciplinary approach encompassing surgery, radiation, and systemic therapy. In the era of personalized oncology, the latter is complemented by various molecularly targeting agents. Precise identification of cellular targets for these drugs requires comprehensive profiling of the cancer genome coupled with an efficient analytic pipeline, leading to an informed decision on drug selection, prognosis, and confirmation of the original pathological diagnosis. Acquisition of optimal tumor tissue for such analysis is paramount and often presents logistical challenges in neurosurgery. Here, we describe the experience and results of the Personalized OncoGenomics (POG) program with a focus on tumors of the central nervous system (CNS). Patients with recurrent CNS tumors were consented and enrolled into the POG program prior to accrual of tumor and matched blood followed by whole-genome and transcriptome sequencing and processing through the POG bioinformatic pipeline. Sixteen patients were enrolled into POG. In each case, POG analyses identified genomic drivers including novel oncogenic fusions, aberrant pathways, and putative therapeutic targets. POG has highlighted that personalized oncology is truly a multidisciplinary field, one in which neurosurgeons must play a vital role if these programs are to succeed and benefit our patients.

A 3D bioprinted hydrogel mesh loaded with all-trans retinoic acid for treatment of glioblastoma.

Treatment of glioblastoma (GBM), as the most lethal type of brain tumor, still remains a major challenge despite the various therapeutic approaches developed over the recent decades. GBM is considered as one of the most therapy-resistant human tumors. Treatment with temozolomide (TMZ) chemotherapy and radiotherapy in GBM patients has led to 30% of two-year survival rate (American Brain Tumor Association), representing a demanding field to develop more effective therapeutic strategies. This study presents a novel method for local delivery of all-trans retinoic acid (ATRA) for targeting GBM cells as a possible adjuvant therapeutic strategy for this disease. We have used 3D bioprinting to fabricate hydrogel meshes laden with ATRA-loaded polymeric particles. The ATRA-loaded meshes have been shown to facilitate a sustained release of ATRA with tunable release rate. Cell viability assay was used to demonstrate the ability of fabricated meshes in reducing cell growth in U-87 MG cell line. We later showed that the developed meshes induced apoptotic cell death in U-87 MG. Furthermore, the use of hydrogel for embedding the ATRA-loaded particles can facilitate the immobilization of the drug next to the tumor site. Our current innovative approach has shown the potential to open up new avenues for treatment of GBM, benefiting patients who suffer from this debilitating disease.

Dose-painted volumetric modulated arc therapy of high-grade glioma using 3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine positron emission tomography.

OBJECTIVE: To determine whether dose painting with volumetric modulated arc therapy for high-grade gliomas using 3,4-dihydroxy-6-[18F]fluoro-l-phenylalanine (18F-FDOPA) positron emission tomography (PET) could achieve dose-escalated coverage of biological target volumes (BTVs) without increasing the dose to cranial organs at risk (OARs). METHODS: 10 patients with high-grade gliomas underwent CT, MRI, and 18F-FDOPA PET/CT images for post-operative radiation therapy planning. Two volumetric modulated arc therapy plans were retrospectively generated for each patient: a conventional plan with 60 Gy in 30 fractions to the planning target volume delineated on MRI and a dose-escalated plan with a maximum dose of 80 Gy in 30 fractions to BTVs. BTVs were created by thresholding 18F-FDOPA PET/CT uptake using a linear quadratic model that assumed tracer uptake was linearly related to tumour cell density. The maximum doses and equivalent uniform doses of OARs were compared. RESULTS: The median volume of the planning target volume receiving at least 95% of the prescribed dose (V 95%) was 99.6% with and 99.5% without dose painting. The median V 95% was >99.2% for BTVs. The maximum doses and equivalent uniform doses to the OARs did not differ significantly between the conventional and dose-painted plans. CONCLUSION: Using commercially available treatment planning software, dose painting for high-grade gliomas was feasible with good BTV coverage and no significant change in the dose to OARs. ADVANCES IN KNOWLEDGE: A novel treatment planning strategy was used to achieve dose painting for gliomas with BTVs obtained from 18F-FDOPA PET/CT using a radiobiological model.

Recent Trends in Neurosurgery Career Outcomes in Canada.

BACKGROUND: As with other specialties, Royal College of Physicians and Surgeons of Canada (RCPSC) trainees in Neurosurgery have anecdotally had challenges securing full-time employment. This study presents the employment status, research pursuits, and fellowship choices of neurosurgery trainees in Canadian programs. METHODS: RCPSC neurosurgery trainees (n = 143) who began their residency training between 1998 and 2008 were included in this study. Associations between year of residency completion, research pursuits, and fellowship choice with career outcomes were determined by Fisher's exact test (p < 0.05, statistical significance). RESULTS: In 2015, 60% and 26% of neurosurgery trainees had permanent positions in Canada and the USA, respectively. Underemployment, defined as locum and clinical associate positions, pursuit of multiple unrelated fellowships, unemployment, and career change to non-surgical career, was 12% in 2015. The proportion of neurosurgery trainees who had been underemployed at some point within 5 years since residency completion was 20%. Pursuit of in-folded research (MSc, PhD, or non-degree research greater than 1 year) was significantly associated with obtaining full employment (94% vs. 73%, p = 0.011). However, fellowship training was not significantly associated with obtaining full employment (78% vs. 75%, p = 1.000). CONCLUSIONS: Underemployment in neurosurgery has become a significant issue in Canada for various reasons. Pursuit of in-folded research, but not fellowship training, was associated with obtaining full employment.

Tendances récentes au Canada en ce qui regarde les possibilités d'emploi en neurochirurgie.Contexte: À l'instar d'autres stagiaires de la médecine spécialisée, des stagiaires en neurochirurgie membres du Collège royal des médecins et des chirurgiens du Canada (CRMCC) ont dit éprouver, selon des données empiriques, des difficultés à obtenir un emploi à plein temps. Cette étude entend présenter la situation professionnelle des stagiaires inscrits dans des programmes canadiens en neurochirurgie ainsi que leurs activités de recherche et leurs choix en matière de bourses de recherche postdoctorale. Méthodes : Des stagiaires membres du CRMCC ayant entrepris leur résidence entre 1998 et 2008 (n = 143) ont été inclus dans cette étude. Les liens pouvant exister entre l'année de résidence complétée, les activités de recherche, les choix en matière de bourses de recherche postdoctorale et les possibilités d'emploi ont été déterminés au moyen du test exact de Fisher (p < 0,05 ; signification statistique). Résultats : En 2015, 60 % des stagiaires en neurochirurgie du Canada disaient compter sur un poste permanent alors qu'ils étaient 26 % à affirmer la même chose aux États-Unis. Le sous-emploi, défini comme par des postes de suppléant (locum) et de clinicien adjoint, par l'obtention de plusieurs bourses de recherche postdoctorale sans liens apparents, par le chômage et par un changement d'orientation excluant la chirurgie, atteignait 12 % la même année. La proportion de stagiaires disant avoir été sous-employés à un moment ou un autre au cours des 5 années de leur résidence était par ailleurs de 20 %. Le fait de mener un projet de recherche dans le cadre de sa résidence (M.Sc., Ph.D. ou en dehors des cycles supérieurs pendant au moins 12 mois) était clairement associé à l'obtention d'un emploi à temps plein (94 % contre 73 % ; p = 0,011). Cela dit, une formation offerte à la suite de l'obtention d'une bourse de recherche postdoctorale n'a pas été associée de manière notable à l'obtention d'un emploi à temps plein (78 % contre 75 % ; p = 1,000). Conclusions : Le sous-emploi en neurochirurgie est désormais un enjeu important au Canada, et ce, pour toutes sortes de raisons. Contrairement aux formations liées à l'obtention d'une bourse de recherche postdoctorale, le fait de mener un projet de recherche régulier a été associé à l'obtention d'un emploi à temps plein.

Impact of work hours and sleep on well-being and burnout for physicians-in-training: the Resident Activity Tracker Evaluation Study.

OBJECTIVE: The Resident Activity Tracker Evaluation (RATE) is a prospective observational study evaluating the impact of work hours, sleep and physical activity on resident well-being, burnout and job satisfaction. BACKGROUND: Physician burnout is common and its incidence is increasing. The impact of work hours and sleep on resident well-being and burnout remains elusive. Activity trackers are an innovative tool for measuring sleep and physical activity. METHODS: Residents were recruited from (i) general surgery and orthopaedics (SURG), (ii) internal medicine and neurology (MED) and (iii) anaesthesia and radiology (RCD). Groups 1 and 2 do not enforce restrictions on the duration of being on-call, and group 3 had restricted the duration of being on-call to 12 hours. Participants wore FitBit trackers for 14 days. Total hours worked, daily sleep, sleep on-call and daily steps were recorded. Participants completed validated surveys assessing self-reported well-being (Short-Form Health Survey), burnout (Maslach Burnout Inventory), and satisfaction with medicine. RESULTS: Surgical residents worked the most hours per week, followed by medical and RCD residents (SURG, 84.3 hours, 95% CI, 80.2-88.5; MED, 69.2 hours, 95% CI, 65.3-73.2; RCD, 52.2 hours, 95% CI, 48.2-56.1; p < 0.001). Surgical residents obtained fewer hours of sleep per day (SURG, 5.9 hours, 95% CI, 5.5-6.3; MED, 6.9 hours, 95% CI, 6.5-7.3; RCD, 6.8 hours, 95% CI, 5.6-7.2; p < 0.001). Nearly two-thirds of participants (61%) scored high burnout on the Maslach depersonalisation subscore. Total steps per day and well-being, burnout and job satisfaction were comparable between groups. Total hours worked, daily sleep and steps per day did not predict burnout or well-being. CONCLUSIONS: Work hours and average daily sleep did not affect burnout. Physical activity did not prevent burnout. Work hour restrictions may lead to increased sleep but may not affect resident burnout or well-being.

Persistent Disparities in Survival for Patients with Glioblastoma.

BACKGROUND: Glioblastoma (GBM) is the most common malignant primary brain cancer in adults. Recent efforts have elucidated genetic features of tumor cells and thus enhanced our knowledge of GBM pathophysiology. The most recent clinical trials report median overall survival between 14 and 20 months. However, population level outcomes are quite variable and there is a paucity of such data within the literature. METHODS: Three hundred seventy-two patients with GBM were diagnosed in the Canadian province of British Columbia between January 2013 and January 2015 and 278 patients had surgery. Of these, 268 had surgery in British Columbia and we have performed a retrospective review of their survival outcomes. RESULTS: Our results indicate a median age of 61.8 years at time of diagnosis, with a slight preponderance of male patients. The median overall survival was 10 months for patients in our cohort. As expected, patients older than the age of 65 and those with worse initial Karnofsky Performance Status scores had a poorer prognosis. Moreover, we have found extent of resection, treatment strategies, and treatment location affect overall survival. CONCLUSIONS: The present study highlights factors that affect patient survival after surgery in British Columbia. Our data are gathered within a single-payer, high-resource setting which removes possible confounders in outcome analysis. We find persistent differences in overall survival when compared with clinical trials and the Surveillance, Epidemiology, and End Results database. Further efforts should ensure access to the gold standard of care. All neuro-oncology centers should analyze the real-world outcomes of their local glioblastoma treatment strategies. Knowledge of the variance from expected and comparative results are fundamental for appropriate patient care.

Patterns of Clinical Use of Stereotactic Laser Ablation: Analysis of a Multicenter Prospective Registry.

BACKGROUND: Stereotactic laser ablation (SLA), also termed laser interstitial thermal therapy, is a minimally invasive procedure that is increasingly used in neurosurgery. We wished to examine how and whether SLA is changing the landscape of treatment options for neurosurgical patients. METHODS: Patients undergoing stereotactic laser ablation were prospectively enrolled in the Laser Ablation of Abnormal Neurological Tissue (LAANTERN) registry. Data from the first 100 enrolled patients are presented here. RESULTS: Clinical indications for SLA include treatment of primary intracranial tumors (48%; 81% being high-grade gliomas [HGGs]), brain metastases (BMs, 34%), epilepsy (16%), and other (2%). For HGGs, SLA was equally likely used for newly diagnosed (45%) or previously treated/recurrent lesions (55%, P = 0.54). By contrast, SLA was predominantly used as treatment for BMs in which radiation therapy/radiosurgery had failed (91%), with only 9% of SLAs performed as initial treatment for newly diagnosed lesions (P < 0.001). Of all SLAs performed, 45% of the procedures were in lieu of surgical resection, with 43% performed because the lesion was not accessible by conventional neurosurgical techniques. CONCLUSION: HGGs and BMs are the leading indications for SLA in the LAANTERN study. For HGGs, SLA is equally used in the presenting or previously treated/recurrent setting. For BMs, SLA is typically used in the recurrent setting. SLAs are equally likely to be performed for difficult-to-access lesions or in lieu of conventional open surgery.

Glioblastoma and chemoresistance to alkylating agents: Involvement of apoptosis, autophagy, and unfolded protein response.

Despite advances in neurosurgical techniques and radio-/chemotherapy, the treatment of brain tumors remains a challenge. This is particularly true for the most frequent and fatal adult brain tumor, glioblastoma (GB). Upon diagnosis, the average survival time of GB patients remains only approximately 15months. The alkylating drug temozolomide (TMZ) is routinely used in brain tumor patients and induces apoptosis, autophagy and unfolded protein response (UPR). Here, we review these cellular mechanisms and their contributions to TMZ chemoresistance in brain tumors, with a particular emphasis on TMZ chemoresistance in glioma stem cells and GB.

Effects of an alveolar recruitment maneuver on subdural pressure, brain swelling, and mean arterial pressure in patients undergoing supratentorial tumour resection: a randomized crossover study.

PURPOSE: Although recruitment maneuvers have been advocated as part of a lung protective ventilation strategy, their effects on cerebral physiology during elective neurosurgery are unknown. Our objectives were to determine the effects of an alveolar recruitment maneuver on subdural pressure (SDP), brain relaxation score (BRS), and cerebral perfusion pressure among patients undergoing supratentorial tumour resection. METHODS: In this prospective crossover study, patients scheduled for resection of a supratentorial brain tumour were randomized to undergo either a recruitment maneuver (30 cm of water for 30 sec) or a "sham" maneuver (5 cm of water for 30 sec), followed by the alternative intervention after a 90-sec equilibration period. Subdural pressure was measured through a dural perforation following opening of the cranium. Subdural pressure and mean arterial pressure (MAP) were recorded continuously. The blinded neurosurgeon provided a BRS at baseline and at the end of each intervention. During each treatment, the changes in SDP, BRS, and MAP were compared. RESULTS: Twenty-one patients underwent the study procedure. The increase in SDP was higher during the recruitment maneuver than during the sham maneuver (difference, 3.9 mmHg; 95% confidence interval [CI], 2.2 to 5.6; P < 0.001). Mean arterial pressure decreased further in the recruitment maneuver than in the sham maneuver (difference, -9.0 mmHg; 95% CI, -12.5 to -5.6; P < 0.001). Cerebral perfusion pressure decreased 14 mmHg (95% CI, 4 to 24) during the recruitment maneuver. The BRS did not change with either maneuver. CONCLUSION: Our results suggest that recruitment maneuvers increase subdural pressure and reduce cerebral perfusion pressure, although the clinical importance of these findings is thus far unknown. This trial was registered with ClinicalTrials.gov, NCT02093117.

Implementation of Neurocritical Care Is Associated With Improved Outcomes in Traumatic Brain Injury.

Background Traditionally, the delivery of dedicated neurocritical care (NCC) occurs in distinct NCC units and is associated with improved outcomes. Institution-specific logistical challenges pose barriers to the development of distinct NCC units; therefore, we developed a consultancy NCC service coupled with the implementation of invasive multimodal neuromonitoring, within a medical-surgical intensive care unit. Our objective was to evaluate the effect of a consultancy NCC program on neurologic outcomes in severe traumatic brain injury patients. METHODS: We conducted a single-center quasi-experimental uncontrolled pre- and post-NCC study in severe traumatic brain injury patients (Glasgow Coma Scale ≤8). The NCC program includes consultation with a neurointensivist and neurosurgeon and multimodal neuromonitoring. Demographic, injury severity metrics, neurophysiologic data, and therapeutic interventions were collected. Glasgow Outcome Scale (GOS) at 6 months was the primary outcome. Multivariable ordinal logistic regression was used to model the association between NCC implementation and GOS at 6 months. RESULTS: A total of 113 patients were identified: 76 pre-NCC and 37 post-NCC. Mean age was 39 years (standard deviation [SD], 2) and 87 of 113 (77%) patients were male. Median admission motor score was 3 (interquartile ratio, 1-4). Daily mean arterial pressure was higher (95 mmHg [SD, 10]) versus (88 mmHg [SD, 10], p<0.001) and daily mean core body temperature was lower (36.6°C [SD, 0.90]) versus (37.2°C [SD, 1.0], p=0.001) post-NCC compared with pre-NCC, respectively. Multivariable regression modelling revealed the NCC program was associated with a 2.5 increased odds (odds ratios, 2.5; 95% confidence interval, 1.1-5.3; p=0.022) of improved 6-month GOS. CONCLUSIONS: Implementation of a NCC program is associated with improved 6 month GOS in severe TBI patients.

Clinical and radiographic response following targeting of BCAN-NTRK1 fusion in glioneuronal tumor.

Glioneuronal tumors constitute a histologically diverse group of primary central nervous system neoplasms that are typically slow-growing and managed conservatively. Genetic alterations associated with glioneuronal tumors include BRAF mutations and oncogenic fusions. To further characterize this group of tumors, we collected a cohort of 26 glioneuronal tumors and performed in-depth genomic analysis. We identified mutations in BRAF (34%) and oncogenic fusions (30%), consistent with previously published reports. In addition, we discovered novel oncogenic fusions involving members of the NTRK gene family in a subset of our cohort. One-patient with BCAN exon 13 fused to NTRK1 exon 11 initially underwent a subtotal resection for a 4th ventricular glioneuronal tumor but ultimately required additional therapy due to progressive, symptomatic disease. Given the patient's targetable fusion, the patient was enrolled on a clinical trial with entrectinib, a pan-Trk, ROS1, and ALK (anaplastic lymphoma kinase) inhibitor. The patient was treated for 11 months and during this time volumetric analysis of the lesion demonstrated a maximum reduction of 60% in the contrast-enhancing tumor compared to his pre-treatment magnetic resonance imaging study. The radiologic response was associated with resolution of his clinical symptoms and was maintained for 11 months on treatment. This report of a BCAN-NTRK1 fusion in glioneuronal tumors highlights its clinical importance as a novel, targetable alteration.

Interhemispheric Difference Images from Postoperative Diffusion Tensor Imaging of Gliomas.

Introduction Determining the full extent of gliomas during radiotherapy planning can be challenging with conventional T1 and T2 magnetic resonance imaging (MRI). The purpose of this study was to develop a method to automatically calculate differences in the fractional anisotropy (FA) and mean diffusivity (MD) values in target volumes obtained with diffusion tensor imaging (DTI) by comparing with values from anatomically homologous voxels on the contralateral side of the brain. Methods Seven patients with a histologically confirmed glioma underwent postoperative radiotherapy planning with 1.5 T MRI and computed tomography. DTI was acquired using echo planar imaging for 20 noncolinear directions with b = 1000 s/mm2 and one additional image with b = 0, repeated four times for signal averaging. The distribution of FA and MD was calculated in the gross tumor volume (GTV), shells 0-5 mm, 5-10 mm, 10-15 mm, 15-20 mm, and 20-25 mm outside the GTV, and the GTV mirrored in the left-right direction (mirGTV). All images were aligned to a template image, and FA and MD interhemispheric difference images were calculated. The difference in mean FA and MD between the regions of interest was statistically tested using two-sided paired t-tests with α = 0.05. Results The mean FA in mirGTV was 0.20 ± 0.04, which was larger than the FA in the GTV (0.12 ± 0.03) and shells 0-5 mm (0.15 ± 0.03) and 5-10 mm (0.17 ± 0.03) outside the GTV. The mean MD (×10-3 mm2/s) in mirGTV was 0.93 ± 0.09, which was smaller than the MD in the GTV (1.48 ± 0.19) and the peritumoral shells. The distribution of FA and MD interhemispheric differences followed the same trends as FA and MD values. Conclusions This study successfully implemented a method for calculation of FA and MD differences by comparison of voxel values with anatomically homologous voxels on the contralateral side of the brain. Further research is warranted to determine if radiotherapy planning using these images can be used to improve target delineation.

Stereotactic Radiosurgery versus Natural History in Patients with Growing Vestibular Schwannomas.

Objective To describe our experience with stereotactic radiosurgery and its efficacy on growing tumors, and then to compare this result with the natural history of a similar cohort of non-radiation-treated lesions. Study Design A retrospective chart review and cohort comparison. Methods The long-term control rates of patients having undergone radiosurgery were collected and calculated, and this population was then compared with a group of untreated patients from the same period of time with growing lesions. Results A total of 61 patients with growing vestibular schwannomas treated with radiosurgery were included. After a mean of 160 months, we observed a control rate of 85.2%. When compared with a group of 36 patients with growing tumors who were yet to receive treatment (previously published), we found a corrected control rate or relative risk reduction of only 76.8%. Conclusion Radiosurgery for growing vestibular schwannomas is less effective than previously reported in unselected series. Although radiosurgery still has a role in managing this disease, consideration should be given to the actual efficacy that may be calculated when the natural history is known. We hope other centers will similarly report their experience on this cohort of patients.

Stereotactic Radiosurgery for Metastases in Eloquent Central Brain Locations.

BACKGROUND: To examine stereotactic radiosurgery (SRS) following whole brain radiotherapy for metastases in eloquent, central brain locations: brainstem, thalamus, and basal ganglia. METHODS: We conducted a retrospective review of patients with metastases in eloquent, central brain locations who were treated with SRS between January 2000 and April 2012. All patients had whole brain radiotherapy. Patients eligible for SRS had one to three brain metastases, metastasis size ≤4 cm, and Karnofsky performance status ≥70. Local progression-free survival and overall survival were calculated using the Kaplan-Meier method. RESULTS: For 24 patients, the median age was 50 years (range, 36-73). Metastases by location were: 11 brainstem, 9 thalamus, and 5 basal ganglia. The median metastasis size was 15 mm (range, 2-33) and the median SRS dose prescription was 15 Gy (range, 12-24). The median local progression-free survival was 13.7 months and median overall survival was 16.4 months. Compared with a cohort of 188 patients with noneloquent brain metastases receiving a median dose of 24 Gy, overall survival of 10.8 months was not significantly different (p=0.16). The only symptomatic complication was grade 2 headache in 8.3%. Asymptomatic adverse radiologic events were radionecrosis in two (8.3%), peritumoural edema in four (16.7%), and hemorrhage in one patient (4.2%). CONCLUSIONS: Lower SRS marginal doses do not appear to compromise survival in patients with eloquently located brain metastases compared with higher doses for other brain metastases, with minimal symptomatic complications.

Population-based outcomes of boost versus salvage radiosurgery for brain metastases after whole brain radiotherapy.

PURPOSE: We conducted a retrospective population-based study to examine the survival outcomes in patients with brain metastases treated with salvage stereotactic radiosurgery (SRS), compared to boost SRS, after previous whole brain radiotherapy (WBRT). METHODS AND MATERIALS: From January 2000 to June 2011, 191 patients treated with WBRT and SRS for brain metastases in British Columbia were studied. Patients were divided into a boost cohort and a salvage cohort. The criteria used to determine eligibility for SRS were: 1-3 metastases, ≤4cm size, Karnofsky performance status ≥ 70, and control of extracranial disease. RESULTS: Diagnosis by primary site was 84 lung, 47 breast, 15 melanoma, 12 renal, 9 colorectal, and 24 other. There were 113 patients (59%) in the boost cohort and 78 patients (41%) in the salvage cohort. The median overall survival from WBRT for the whole population was 17.7months: 12.1 months for the boost cohort and 22.7 months for the salvage cohort. There was no difference in median survival after SRS for the boost and salvage cohorts (11.2 vs. 11.2 months, p=0.78). CONCLUSIONS: In selected patients with brain metastases treated with WBRT, survival following salvage SRS is as good as survival after WBRT + boost SRS.

Disulfiram, a drug widely used to control alcoholism, suppresses the self-renewal of glioblastoma and over-rides resistance to temozolomide.

Glioblastomas (GBM) are associated with high rates of relapse. These brain tumors are often resistant to chemotherapies like temozolomide (TMZ) and there are very few treatment options available to patients. We recently reported that polo-like kinase-1 (PLK1) is associated with the proliferative subtype of GBM; which has the worst prognosis. In this study, we addressed the potential of repurposing disulfiram (DSF), a drug widely used to control alcoholism for the past six decades. DSF has good safety profiles and penetrates the blood-brain barrier. Here we report that DSF inhibited the growth of TMZ resistant GBM cells, (IC90=100 nM), but did not affect normal human astrocytes. At similar DSF concentrations, self-renewal was blocked by ~100% using neurosphere growth assays. Likewise the drug completely inhibited the self-renewal of the BT74 and GBM4 primary cell lines. Additionally, DSF suppressed growth and self-renewal of primary cells from two GBM tumors.These cells were resistant to TMZ, had unmethylated MGMT, and expressed high levels of PLK1. Consistent with its role in suppressing GBM growth, DSF inhibited the expression of PLK1 in GBM cells. Likewise, PLK1 inhibition with siRNA, or small molecules (BI-2536 or BI-6727) blocked growth of TMZ resistant cells. Our studies suggest that DSF has the potential to be repurposed for treatment of refractory GBM.