Recent Surgical Management of Gliomas

Circumferential sulcus-guided resection technique for improved outcomes of low-grade gliomas

OBJECTIVE

Many neurosurgeons resect nonenhancing low-grade gliomas (LGGs) by using an inside-out piecemeal resection (PMR) technique. At the authors' institution they have increasingly used a circumferential, perilesional, sulcus-guided resection (SGR) technique. This technique has not been well described and there are limited data on its effectiveness. The authors describe the SGR technique and assess the extent to which SGR correlates with extent of resection and neurological outcome.

METHODS

The authors identified all patients with newly diagnosed LGGs who underwent resection at their institution over a 22-year period. Demographics, presenting symptoms, intraoperative data, method of resection (SGR or PMR), volumetric imaging data, and postoperative outcomes were obtained. Univariate analyses used ANOVA and Fisher's exact test. Multivariate analyses were performed using multivariate logistic regression.

RESULTS

Newly diagnosed LGGs were resected in 519 patients, 208 (40%) using an SGR technique and 311 (60%) using a PMR technique. The median extent of resection in the SGR group was 84%, compared with 77% in the PMR group (p = 0.019). In multivariate analysis, SGR was independently associated with a higher rate of complete (100%) resection (27% vs 18%) (OR 1.7, 95% CI 1.1-2.6; p = 0.03). SGR was also associated with a statistical trend toward lower rates of postoperative neurological complications (11% vs 16%, p = 0.09). A subset analysis of tumors located specifically in eloquent brain demonstrated SGR to be as safe as PMR.

CONCLUSIONS

The authors describe the SGR technique used to resect LGGs and show that SGR is independently associated with statistically significantly higher rates of complete resection, without an increase in neurological complications, than with PMR. SGR technique should be considered when resecting LGGs.

Early Surgery Prolongs Professional Activity in IDH Mutant Low-Grade Glioma Patients: A Policy Change Analysis

Background

Until 2015, Dutch guidelines recommended follow-up and biopsy rather than surgery as initial care for suspected low-grade gliomas (LGG). Given evidence that surgery could extend patient survival, our center stopped following this guideline on January 1, 2010 and opted for early maximal safe resection of LGG. The effects of early surgery on the ability of patients to work remains little documented.

Methods

A total of 104 patients operated on at our center between January 2000 and April 2013 and diagnosed with the WHO 2016 grade 2 astrocytoma, IDH mutant or oligodendroglioma, IDH mutant and deleted 1p19q were included. The clinical characteristics, survival, and work history of patients operated on before or after January 2010 were obtained from the patients' records and compared. The minimal follow-up was 8 years.

Results

As per policy change, the interval between radiological diagnosis and first surgery decreased significantly after 2010. Likewise, before 2010, 25.8% of tumors were initially biopsied, 51.6% were resected under anesthesia, and 22.5% under awake conditions versus 14.3%, 23.8%, and 61.9% after this date (p < 0.001). The severity of permanent postoperative neurological deficits decreased after 2010. In total, 82.5% of the patients returned to work postoperatively before 2010 versus 100% after 2010. The postoperative control of epilepsy increased significantly after 2010 (74.4% vs. 47.9%). The median time from diagnosis to a definitive incapacity to work increased by more than 2 years after 2010 (88.7 vs. 62.2 months).

Conclusion

A policy shift towards early aggressive surgical treatment of IDH mutant LGG is safe and prolongs the patients' ability to work.

Sterile Gelatin Film Reduces Cortical Injury Associated With Brain Tumor Re-Resection

BACKGROUND

Recurrent intracranial tumors frequently require re-resection. Dural adhesions to the cortex increase the morbidity and duration of these revision craniotomies.

OBJECTIVE

To describe the use of commercially available sterile gelatin film to prevent meningocerebral adhesions and decrease the rate of surgically induced ischemia from revision craniotomy.

METHODS

This retrospective cohort study examined patients with recurrent glioma, meningioma, and metastasis who underwent re-resection at least 30 d following their initial tumor resection. Cortical surface tissue ischemia after re-resection on diffusion-weighted magnetic resonance imaging was compared for patients with (gelatin film group) and without (nongelatin film group) a history of gelatin film placement at the conclusion of their initial tumor resection.

RESULTS

A total of 84 patients in the gelatin film group were compared to 86 patients in the nongelatin film group. Patient age, sex, tumor pathology, tumor volume, tumor eloquence, laterality of surgical approach, history of radiotherapy, and time interval between resections did not differ between groups. Radiographic evidence of cortical ischemia following reoperation was less prevalent in the gelatin film group (13.1% vs 32.6%; P < .01). In multivariate logistic regression analysis, no gelatin film (P < .01) and larger tumor size (P = .02) predicted cortical surface ischemia following revision craniotomy. Postoperative complications in the gelatin film and nongelatin film group otherwise did not differ.

CONCLUSION

Routine placement of commercially available sterile gelatin film on the cortex prior to dural closure is associated with decreased surgically induced tissue ischemia at the time of revision tumor craniotomy.

Navigated Intraoperative 2-Dimensional Ultrasound in High-Grade Glioma Surgery: Impact on Extent of Resection and Patient Outcome

BACKGROUND

Maximizing extent of resection (EOR) and reducing residual tumor volume (RTV) while preserving neurological functions is the main goal in the surgical treatment of gliomas. Navigated intraoperative ultrasound (N-ioUS) combining the advantages of ultrasound and conventional neuronavigation (NN) allows for overcoming the limitations of the latter.

OBJECTIVE

To evaluate the impact of real-time NN combining ioUS and preoperative magnetic resonance imaging (MRI) on maximizing EOR in glioma surgery compared to standard NN.

METHODS

We retrospectively reviewed a series of 60 cases operated on for supratentorial gliomas: 31 operated under the guidance of N-ioUS and 29 resected with standard NN. Age, location of the tumor, pre- and postoperative Karnofsky Performance Status (KPS), EOR, RTV, and, if any, postoperative complications were evaluated.

RESULTS

The rate of gross total resection (GTR) in NN group was 44.8% vs 61.2% in N-ioUS group. The rate of RTV > 1 cm3 for glioblastomas was significantly lower for the N-ioUS group (P < .01). In 13/31 (42%), RTV was detected at the end of surgery with N-ioUS. In 8 of 13 cases, (25.8% of the cohort) surgeons continued with the operation until complete resection. Specificity was greater in N-ioUS (42% vs 31%) and negative predictive value (73% vs 54%). At discharge, the difference between pre- and postoperative KPS was significantly higher for the N-ioUS (P < .01).

CONCLUSION

The use of an N-ioUS-based real-time has been beneficial for resection in noneloquent high-grade glioma in terms of both EOR and neurological outcome, compared to standard NN. N-ioUS has proven usefulness in detecting RTV > 1 cm3.

Functional characteristics of the human primary somatosensory cortex: An electrostimulation study

The common knowledge of the functional organization of the human primary somatosensory cortex (S1) had been primarily established by Penfield who electrically stimulated the exposed surface [referred as Brodmann area (BA)1] of S1 under neurosurgical conditions. Nevertheless, the functional information regarding the deep surface (BA 2 and 3) of S1 is poorly understood. We retrospectively analyzed all the clinical manifestations induced by extra-operative cortical electrical stimulation (ES) in 33 patients with medically intractable epilepsy who underwent stereo-electroencephalography (SEEG) monitoring for presurgical assessment. Demographic and clinical data were gathered and evaluated to delineate the determinants of the occurrence of positive responses, types of responses, and size of body regions involved. The stimulation of 244 sites in S1 yielded 198 positive sites (81.1%), most of which were located in the sulcal cortex. In multivariable analyses, no clinical or demographic factors predicted the occurrence of responses or their threshold levels. The size of body region involved in the responses had ordinal association with the stimulated BA sites (p < 0.001). Various types of responses elicited from the S1 were documented and classified, and the predictors of those responses were also assessed. Our analysis revealed the functional characteristics of the entire S1 and proved the multiplicity of functions of S1.

Identification and validation of potential novel prognostic biomarkers for patients with glioma based on a gene co-expression network

BACKGROUND

Glioma is widely regarded as one of most lethal and challenging diseases of the nervous system. The aim of this study was to identify novel biomarkers that offer better prognosis prediction for Chinese patients with glioma.

METHODS

By using systematic approaches, the co-expression modules were identified from the Chinese Glioma Genome Atlas (CGGA) database through weighted gene co-expression network analysis and functional enrichment of essential modules of Kyoto Encyclopedia of Genes and Genomes terms. The co-expression modules were validated using The Cancer Genome Atlas database and the protein-protein interaction (PPI) network.

RESULTS

For network construction, 5,374 among 21,494 genes were selected, and an increasing genetic variance was associated with the prognosis of glioma. By using functional enrichment analysis, the involvement of multiple vital processes, including metabolism of fatty acids, was correlated with the patient prognosis. Notably, five hub genes (KCNB1, UST, SOX8, KLHL42, and HDAC4) were identified for these processes. Accordingly, using the Kaplan-Meier method, there was enhanced expression of these genes in patients with significantly lower overall survival rates, especially those from the CGGA database.

CONCLUSIONS

This study not only revealed the essential co-expression gene modules in patients with glioma, but it also unraveled the potential signaling pathways underlying these functional processes.

Upfront Magnetic Resonance Imaging-Guided Stereotactic Laser-Ablation in Newly Diagnosed Glioblastoma: A Multicenter Review of Survival Outcomes Compared to a Matched Cohort of Biopsy-Only Patients

BACKGROUND

Laser ablation (LA) is used as an upfront treatment in patients with deep seated newly diagnosed Glioblastoma (nGBM).

OBJECTIVE

To evaluate the outcomes of LA in patients with nGBM and compare them with a matched biopsy-only cohort.

METHODS

Twenty-four nGBM patients underwent upfront LA at Cleveland clinic, Washington University in St. Louis, and Yale University (6/2011-12/2014) followed by chemo/radiotherapy. Also, 24 out of 171 nGBM patients with biopsy followed by chemo/radiotherapy were matched based on age (< 70 vs ≥ 70), gender, tumor location (deep vs lobar), and volume (<11 cc vs ≥11 cc). Progression-free survival (PFS), overall survival (OS), and disease-specific PFS and OS were outcome measures. Three prognostic groups were identified based on extent of tumor ablation by thermal-damage-threshold (TDT)-lines.

RESULTS

The median tumor volume in LA (n = 24) and biopsy only (n = 24) groups was 9.3 cm3 and 8.2 cm3 respectively. Overall, median estimate of OS and PFS in LA cohort was 14.4 and 4.3 mo compared to 15.8 mo and 5.9 mo for biopsy only cohort. On multivariate analysis, favorable TDT-line prognostic groups were associated with lower incidence of disease specific death (P = .03) and progression (P = .05) compared to other groups including biopsy only cohort. Only age (<70 yr, P = .02) and tumor volume (<11 cc, P = .03) were favorable prognostic factors for OS.

CONCLUSION

The maximum tumor coverage by LA followed by radiation/chemotherapy is an effective treatment modality in patients with nGBM, compared to biopsy only cohort. The TDT-line prognostic groups were independent predictor of disease specific death and progression after LA.

Glioblastoma: Pathogenesis and Current Status of Chemotherapy and Other Novel Treatments

Glioblastoma is one of the most common and detrimental forms of solid brain tumor, with over 10,000 new cases reported every year in the United States. Despite aggressive multimodal treatment approaches, the overall survival period is reported to be less than 15 months after diagnosis. A widely used approach for the treatment of glioblastoma is surgical removal of the tumor, followed by radiotherapy and chemotherapy. While there are several drugs available that are approved by the Food and Drug Administration (FDA), significant efforts have been made in recent years to develop new chemotherapeutic agents for the treatment of glioblastoma. This review describes the molecular targets and pathogenesis as well as the current progress in chemotherapeutic development and other novel therapies in the clinical setting for the treatment of glioblastoma.

Setup presentation and clinical outcome analysis of treating highly language-eloquent gliomas via preoperative navigated transcranial magnetic stimulation and tractography

OBJECTIVE Awake surgery combined with intraoperative direct electrical stimulation (DES) and intraoperative neuromonitoring (IONM) is considered the gold standard for the resection of highly language-eloquent brain tumors. Different modalities, such as functional magnetic resonance imaging (fMRI) or magnetoencephalography (MEG), are commonly added as adjuncts for preoperative language mapping but have been shown to have relevant limitations. Thus, this study presents a novel multimodal setup consisting of preoperative navigated transcranial magnetic stimulation (nTMS) and nTMS-based diffusion tensor imaging fiber tracking (DTI FT) as an adjunct to awake surgery. METHODS Sixty consecutive patients (63.3% men, mean age 47.6 ± 13.3 years) suffering from highly language-eloquent left-hemispheric low- or high-grade glioma underwent preoperative nTMS language mapping and nTMS-based DTI FT, followed by awake surgery for tumor resection. Both nTMS language mapping and DTI FT data were available for resection planning and intraoperative guidance. Clinical outcome parameters, including craniotomy size, extent of resection (EOR), language deficits at different time points, Karnofsky Performance Scale (KPS) score, duration of surgery, and inpatient stay, were assessed. RESULTS According to postoperative evaluation, 28.3% of patients showed tumor residuals, whereas new surgery-related permanent language deficits occurred in 8.3% of patients. KPS scores remained unchanged (median preoperative score 90, median follow-up score 90). CONCLUSIONS This is the first study to present a clinical outcome analysis of this very modern approach, which is increasingly applied in neurooncological centers worldwide. Although human language function is a highly complex and dynamic cortico-subcortical network, the presented approach offers excellent functional and oncological outcomes in patients undergoing surgery of lesions affecting this network.

How is stereotactic brain biopsy evolving? A multicentric analysis of a series of 421 cases treated in Rome over the last sixteen years

OBJECTIVE

In recent decades, frame-based (FBB) and frame-less stereotactic brain biopsy (FLB) have played a crucial role in defining the diagnosis and management of expanding intracranial lesions in critical areas. During the same period, there have been significant advances in diagnostic imaging, a shift in surgical strategies towards extensive resection in gliomas and new molecular classification of brain tumors. Taking these advances into account, we have evaluated whether significant changes have occurred over the last sixteen years of our clinical practice in terms of frequency, indications, target selection, and the histologic results of stereotactic brain biopsy (SBB) procedures.

PATIENTS AND METHODS

We analyzed a series of 421 SBB cases treated between January 2002 and June 2017 in three major neurosurgical institutes in Rome, serving a total of 1.5 million people. Within this series, 94.8% of patients underwent FBB, while, more recently, FLB was performed in 5.2% of cases. The entire period under consideration, running from 2002 to 2017, has been further stratified into four-year time-frames (2002-2005, 2006-2009, 2010-2013, 2014-2017) for the purpose of analysis.

RESULTS

The diagnostic yield was 97%. Final diagnoses revealed tumors in 90% of cases and non-neoplastic masses in 7%, while 3% of cases were not conclusive. The morbidity rate was 3% (12 cases) and mortality was 0.7% (3 cases). Intra-operative frozen sections were made in 78% of biopsies. In our three institutes, the number of SBBs decreased steadily throughout the time-frames under consideration. We have also observed a statistically significant reduction in biopsy procedures in lobar lesions, while those performed on the basal ganglia increased and the number of SBBs of multiple masses and lesions of the corpus callosum remained stable. Primary central nervous system diagnosis of lymphomas (PCNSL) was the sole diagnosis whose incidence increased significantly.

CONCLUSIONS

Over the last sixteen years, we have witnessed a significant decrease in SBB procedures and a modification in target selection and histologic results. Despite the significant evolution of neuroimaging, an accurate non-invasive diagnosis of intracranial expanding lesions has not yet been achieved. Furthermore, the most recent WHO classification of brain tumors (2016), which incorporates molecular and morphological features, has boosted the need for molecular processing of tissue samples in all expanding brain lesions. For these reasons, it is likely that SBBs will continue to be performed in specific cases, playing a significant role in diagnostic confirmation by providing tissue samples, so as to better assess the biology and the prognosis of cerebral lesions, as well as their sensitivity to standard radio-chemotherapy or to new molecular target therapies.

Pre- and post-surgery MRSI predictive value in adult oligodendroglioma prognosis

PURPOSE

The aim of this study was to study the relationship between MRSI, before and after surgery, and patient survival. The accuracy of pre-operative MRSI in differentiating low- from high-grade oligodendrogliomas (ODGs) was also studied.

METHODS

Two hundred patients with ODG were retrospectively included in this study between 2000 and 2016. All patients underwent MRSI before any treatment or biopsy and/or after surgery for an intra-axial brain tumour. The R software was used for statistical data analysis. p < 0.05 was considered statistically significant. Kaplan-Meier curves were calculated for patients with low-grade ODG and high-grade ODG pre- and post-operatively, to study survival (overall survival, OS). The best threshold of each MRSI metabolite ratio was obtained using receiver operating characteristic curves (ROCs).

RESULTS

One hundred patients underwent pre-operative MRSI and 170 post-operative MRSI. N-acetylaspartate (NAA), lactate (Lac), choline (Cho) and creatine (Cr) were measured. Kapan-Meier curves showed that survival was poorer for a nCho/Cr > 3.02 in the pre-operative and nCho/Cr > 2.04, Lac/Cr > 0.743 and nCho/NAA > 3.63 in the post-operative period. Post-operative MRSI predicts survival better than pre-operative MRSI. nCho/Cr and Lac/Cr distinguished low- from high-grade ODG with a good positive predictive value.

CONCLUSION

MRSI is associated with survival. It is a non-invasive tool which completes histopathology and can predict patients' prognosis, thus improving patient management.

Is non-awake surgery for supratentorial adult low-grade glioma treatment still feasible?

In this short review, the author performs a database search, summarizes, and discusses studies that provide information on the need to perform awake surgery to preserve quality of life/return to work of adult patients who undergo resection for a supratentorial low-grade glioma (LGG). Based upon the currently available data, the author concludes that in LGG, patients with no or only mild deficits at diagnosis, non-awake surgery can no longer be achieved. Indeed, awake craniotomy with intrasurgical electrical mapping has resulted in an increase of the extent of resection and overall survival in LGG. Furthermore, in order to resume a normal familial, social, and professional life, LGG patients with a prolonged survival expectancy have to benefit not only from language mapping when the tumor involves the left "dominant" hemisphere, but also from intraoperative mapping of sensorimotor, visuospatial, higher cognitive, and emotional functions under local anesthesia, even for gliomas situated within presumed "non-language" areas such as the right "non-dominant" hemisphere. In other words, the ultimate goal is to map the functional connectome for each patient in order to perform the resection up to the eloquent networks and then to optimize the onco-functional balance of LGG surgery. To this end, an objective neuropsychological assessment has to be achieved in a more systematic manner before and after resection. Early postoperative cognitive rehabilitation is also recommended, whenever needed.

Predicting brain tumor regrowth in relation to motor areas by functional brain mapping

Background

Due to frequent recurrences, high-grade gliomas still confer a poor prognosis. Several regrowth prediction models have been developed, but most of these models are based on cellular models or dynamic mathematical calculations, thus limiting direct clinical use. The present study aims to evaluate whether navigated transcranial magnetic stimulation (nTMS) or functional magnetic resonance imaging (fMRI) may be used to predict the direction of tumor regrowth.

Methods

Sixty consecutive patients with high-grade gliomas were enrolled prospectively and analyzed in a case-control design after tumor recurrence. All patients underwent serial MRI after surgery and suffered from recurrent tumors during a mean follow-up of 13.2 ± 14.9 months. Tumor regrowth speed and direction were measured in relation to motor areas defined by nTMS, nTMS-based tractography, and fMRI. Depending on initial resection, patients were separated into three groups (group 1: without residual tumor, group 2: residual tumor away from motor areas, and group 3: residual tumor facing motor areas).

Results

Sixty-nine percent of patients in group 1, 64.3% in group 2, and 66.7% in group 3 showed tumor recurrence towards motor eloquence on contrast-enhanced T1-weighted sequences (P = .9527). Average growth towards motor areas on contrast-enhanced T1-weighted sequences was 0.6 ± 1.5 (group 1), 0.6 ± 2.4 (group 2), and 2.3 ± 5.5 (group 3) mm/month (P = .0492).

Conclusion

This study suggests a new strategy to predict tumor regrowth patterns in high-grade glioma patients. Our approach could be directly applied in the clinical setting, thus having clinical impact on both surgical treatment and radiotherapy planning.

Ethics Committee Registration Number

2793/10.

Identification of potential key genes associated with glioblastoma based on the gene expression profile

Gliomas are serious primary brain tumors. The aim of the present study was to identify potential key genes associated with the progression of gliomas. The GSE31262 gene expression profile data, which included 9 glioblastoma stem cells (GSCs) samples and 5 neural stem cell samples from adult humans, were downloaded from Gene Expression Omnibus (GEO) database. limma package was used to identify differentially expressed genes (DEGs). Based on STRING database and Pearson Correlation Coefficient (PCC), a co-expression network was constructed to comprehensively understand the interactions between DEGs, and function analysis of genes in the network was conducted. Furthermore, the DEGs that were associated with prognosis were analyzed. A total of 431 DEGs were identified, including 98 upregulated DEGs and 333 downregulated DEGs. Genes including PDZ binding kinase, topoisomerase (DNA) II α (TOP2A), cyclin dependent kinase (CDK) 1, cell division cycle 6 and NIMA related kinase 2 had a relatively high degree in the co-expression network. A set of genes including cyclin D1, CDK1 and CDK2 were significantly enriched in the cell cycle and p53 signaling pathway. Additionally, 69 DEGs were identified as genes involved in glioblastoma prognosis, such as CDK2 and TOP2A. The genes that had a higher degree and were associated with cell cycle and p53 signaling pathway may play pivotal roles in the progress of glioblastoma.

Impact of removed tumor volume and location on patient outcome in glioblastoma

Glioblastoma is an aggressive primary brain tumor with devastatingly poor prognosis. Multiple studies have shown the benefit of wider extent of resection (EOR) on patient overall survival (OS) and worsened survival with larger preoperative tumor volumes. However, the concomitant impact of postoperative tumor volume and eloquent location on OS has yet to be fully evaluated. We performed a retrospective chart review of adult patients treated for glioblastoma from January 2006 through December 2011. Adherence to standardized postoperative chemoradiation protocols was used as an inclusion criterion. Detailed volumetric and location analysis was performed on immediate preoperative and immediate postoperative magnetic resonance imaging. Cox proportional hazard modeling approach was employed to explore the modifying effects of EOR and eloquent location after adjusting for various confounders and associated characteristics, such as preoperative tumor volume and demographics. Of the 471 screened patients, 141 were excluded because they did not meet all inclusion criteria. The mean (±SD) age of the remaining 330 patients (60.6% male) was 58.9 ± 12.9 years; the mean preoperative and postoperative Karnofsky performance scores (KPSs) were 76.2 ± 10.3 and 80.0 ± 16.6, respectively. Preoperative tumor volume averaged 33.2 ± 29.0 ml, postoperative residual was 4.0 ± 8.1 ml, and average EOR was 88.6 ± 17.6%. The observed average follow-up was 17.6 ± 15.7 months, and mean OS was 16.7 ± 14.4 months. Survival analysis showed significantly shorter survival for patients with lesions in periventricular (16.8 ± 1.7 vs. 21.5 ± 1.4 mo, p = 0.03), deep nuclei/basal ganglia (11.6 ± 1.7 vs. 20.6 ± 1.2, p = 0.002), and multifocal (12.0 ± 1.4 vs. 21.3 ± 1.3 months, p = 0.0001) locations, but no significant influence on survival was seen for eloquent cortex sites (p = 0.14, range 0.07-0.9 for all individual locations). OS significantly improved with EOR in univariate analysis, averaging 22.3, 19.7, and 13.2 months for >90, 80-90, and 70-80% resection, respectively. Survival was 22.8, 19.0, and 12.7 months for 0, 0-5, and 5-10 ml postoperative residual, respectively. A hazard model showed that larger preoperative tumor volume [hazard ratio (HR) 1.05, 95% CI 1.02-1.07], greater age (HR 1.02, 95% CI 1.01-1.03), multifocality (HR 1.44, 95% CI 1.01-2.04), and deep nuclei/basal ganglia (HR 2.05, CI 1.27-3.3) were the most predictive of poor survival after adjusting for KPS and tumor location. There was a negligible but significant interaction between EOR and preoperative tumor volume (HR 0.9995, 95% CI 0.9993-0.9998), but EOR alone did not correlate with OS after adjusting for other factors. The interaction between EOR and preoperative tumor volume represented tumor volume removed during surgery. In conclusion, EOR alone was not an important predictor of outcome during GBM treatment once preoperative tumor volume, age, and deep nuclei/basal ganglia location were factored. Instead, the interaction between EOR and preoperative volume, representing reduced disease burden, was an important predictor of reducing OS. Removal of tumor from eloquent cortex did not impact postoperative KPS. These results suggest aggressive surgical treatment to reduce postoperative residual while maintaining postoperative KPS may aid patient survival outcomes for a given tumor size and location.

Novel Molecular Multilevel Targeted Antitumor Agents

A multifunctional fusion protein, IL-13.E13K-D2-NLS, effectively recognizes glioblastoma (GBM) cells and delivers its portion to the cell nucleus. IL-13.E13K-D2-NLS is composed of a cancer cell targeting ligand (IL-13.E13K), specialized cytosol translocation bacterial toxin domain 2 of Pseudomonas exotoxin A (D2) and SV40 T antigen nuclear localization signal (NLS). We have now tested whether we can produce proteins that would serve as a delivery vehicle to lysosomes and mitochondria as well. Moreover, we examined whether IL-13.E13K-D2-NLS can deliver anti-cancer drugs like doxorubicin to their nuclear site of action in cancer cells. We have thus constructed two novel proteins: IL-13.E13K-D2-LLS which incorporates lysosomal localization signal (LLS) of a human lysosomal associated membrane protein (LAMP-1) for targeting to lysosomes and IL-13-D2-KK2, which incorporates a pro-apoptotic peptide (KLAKLAK)2 (KK2) exerting its action in mitochondria. Furthermore, we have produced IL-13.E13K-D2-NLS and IL-13.E13K-D2-LLS versions containing a cysteine for site-specific conjugation with a modified doxorubicin, WP936. We found that single-chain recombinant proteins IL-13.E13K-D2-LLS and IL-13-D2-KK2 are internalized and localized mostly to the lysosomal and mitochondrial compartments, respectively, without major trafficking to cells' nuclei. We also determined that IL-13.E13K-D2-NLS-cys[WP936], IL-13.E13K-D2-LAMP-cys[WP936] and IL-13-D2-KK2 were cytotoxic to GBM cells overexpressing IL-13RA2, while much less cytotoxic to GBM cell lines expressing low levels of the receptor. IL-13.E13K-D2-NLS-cys[WP936] was the most potent of the tested anti-tumor agents including free WP936. We believe that our receptor-directed intracellular organelle-targeted proteins can be employed for numerous specific and safer treatment applications when drugs have specific intracellular sites of their action.

Malignant transformation of low-grade gliomas in patients undergoing adjuvant therapy

Low-grade gliomas (LGG) comprise nearly 15-20 % of all central nervous system glial tumors. Several factors have been recognized as playing role in LGG malignant transformation (MT). A breakthrough analysis of a multidisciplinary group pointed that temozolomide may play a role in MT of LGGs. We analyzed the prevalence of MT in LGG patients submitted to adjuvant therapy (AT). We analyzed the medical charts of 43 patients with LGG submitted to surgery or biopsy and attending at Hospital do Servidor Público Estadual de São Paulo (São Paulo, Brazil), consecutively diagnosed from 1995 to 2013. 43 patients (24 women and 19 men) were evaluated, with mean age of 45.3 years. According to histology, 30 were astrocytomas (70 %), 12 (27 %) were oligodendrogliomas, and 1 (3 %) were mixed glioma. Mean follow-up time was 4.2 years with the standard deviation of 2.1. Twenty-eight patients did not receive adjuvant therapy and 15 received adjuvant therapy. From 43 patients with complete follow-up, 21 (48 %) experienced malignant transformation. Among such patients, nine were users of AT. Forty-eight percent of patients presented MT, being 60 % in the AT group and 42.8 % without AT. Our analysis revealed a high prevalence of MT in patients undergoing AT, higher than in patients without AT.

Passive language mapping combining real-time oscillation analysis with cortico-cortical evoked potentials for awake craniotomy

OBJECTIVE

Electrocortical stimulation (ECS) is the gold standard for functional brain mapping; however, precise functional mapping is still difficult in patients with language deficits. High gamma activity (HGA) between 80 and 140 Hz on electrocorticography is assumed to reflect localized cortical processing, whereas the cortico-cortical evoked potential (CCEP) can reflect bidirectional responses evoked by monophasic pulse stimuli to the language cortices when there is no patient cooperation. The authors propose the use of “passive” mapping by combining HGA mapping and CCEP recording without active tasks during conscious resections of brain tumors.

METHODS

Five patients, each with an intraaxial tumor in their dominant hemisphere, underwent conscious resection of their lesion with passive mapping. The authors performed functional localization for the receptive language area, using real-time HGA mapping, by listening passively to linguistic sounds. Furthermore, single electrical pulses were delivered to the identified receptive temporal language area to detect CCEPs in the frontal lobe. All mapping results were validated by ECS, and the sensitivity and specificity were evaluated.

RESULTS

Linguistic HGA mapping quickly identified the language area in the temporal lobe. Electrical stimulation by linguistic HGA mapping to the identified temporal receptive language area evoked CCEPs on the frontal lobe. The combination of linguistic HGA and frontal CCEPs needed no patient cooperation or effort. In this small case series, the sensitivity and specificity were 93.8% and 89%, respectively.

CONCLUSIONS

The described technique allows for simple and quick functional brain mapping with higher sensitivity and specificity than ECS mapping. The authors believe that this could improve the reliability of functional brain mapping and facilitate rational and objective operations. Passive mapping also sheds light on the underlying physiological mechanisms of language in the human brain.

Complications of ventricular entry during craniotomy for brain tumor resection

OBJECTIVE Recent studies have demonstrated that periventricular tumor location is associated with poorer survival and that tumor location near the ventricle limits the extent of resection. This finding may relate to the perception that ventricular entry leads to further complications and thus surgeons may choose to perform less aggressive resection in these areas. However, there is little support for this view in the literature. This study seeks to determine whether ventricular entry is associated with more complications during craniotomy for brain tumor resection. METHODS A retrospective analysis of patients who underwent craniotomy for tumor resection at Henry Ford Hospital between January 2010 and November 2012 was conducted. A total of 183 cases were reviewed with attention to operative entry into the ventricular system, postoperative use of an external ventricular drain (EVD), subdural hematoma, hydrocephalus, and symptomatic intraventricular hemorrhage (IVH). RESULTS Patients in whom the ventricles were entered had significantly higher rates of any complication (46% vs 21%). Complications included development of subdural hygroma, subdural hematoma, intraventricular hemorrhage, subgaleal collection, wound infection, urinary tract infection/deep venous thrombosis, hydrocephalus, and ventriculoperitoneal (VP) shunt placement. Specifically, these patients had significantly higher rates of EVD placement (23% vs 1%, p < 0.001), hydrocephalus (6% vs 0%, p = 0.03), IVH (14% vs 0%, p < 0.001), infection (15% vs 5%, p = 0.04), and subgaleal collection (20% vs 4%, p < 0.001). It was also observed that VP shunt placement was only seen in cases of ventricular entry (11% vs 0%, p = 0.001) with 3 of 4 of these patients having a large ventricular entry (defined here as entry greater than a pinhole [< 3 mm] entry). Furthermore, in a subset of glioblastoma patients with and without ventricular entry, Kaplan-Meier estimates for survival demonstrated a median survival time of 329 days for ventricular entry compared with 522 days for patients with no ventricular entry (HR 1.13, 95% CI 0.65-1.96; p = 0.67). CONCLUSIONS There are more complications associated with ventricular entry during brain tumor resection than in nonviolated ventricular systems. Better strategies for management of periventricular tumor resection should be actively sought to improve resection and survival for these patients.

World Health Organization grade II-III astrocytomas consist of genetically distinct tumor lineages

Recent investigations revealed genetic analysis provides important information in management of gliomas, and we previously reported grade II-III gliomas could be classified into clinically relevant subgroups based on the DNA copy number aberrations (CNAs). To develop more precise genetic subgrouping, we investigated the correlation between CNAs and mutational status of the gene encoding isocitrate dehydrogenase (IDH) of those tumors. We analyzed the IDH status and CNAs of 174 adult supratentorial gliomas of astrocytic or oligodendroglial origin by PCR-based direct sequencing and comparative genomic hybridization, respectively. We analyzed the relationship between genetic subclassification and clinical features. We found the most frequent aberrations in IDH mutant tumors were the combined whole arm-loss of 1p and 19q (1p/19q codeletion) followed by gain on chromosome arm 7q (+7q). The gain of whole chromosome 7 (+7) and loss of 10q (-10q) were detected in IDH wild-type tumors. Kaplan-Meier estimates for progression-free survival showed that the tumors with mutant IDH, -1p/19q, or +7q (in the absence of +7p) survived longer than tumors with wild-type IDH, +7, or -10q. As tumors with +7 (IDH wild-type) showed a more aggressive clinical nature, they are probably not a subtype that developed from the slowly progressive tumors with +7q (IDH mutant). Thus, tumors with a gain on chromosome 7 (mostly astrocytic) comprise multiple lineages, and such differences in their biological nature should be taken into consideration during their clinical management.

Revealing humans' sensorimotor functions with electrical cortical stimulation

Direct electrical stimulation (DES) of the human brain has been used by neurosurgeons for almost a century. Although this procedure serves only clinical purposes, it generates data that have a great scientific interest. Had DES not been employed, our comprehension of the organization of the sensorimotor systems involved in movement execution, language production, the emergence of action intentionality or the subjective feeling of movement awareness would have been greatly undermined. This does not mean, of course, that DES is a gold standard devoid of limitations and that other approaches are not of primary importance, including electrophysiology, modelling, neuroimaging or psychophysics in patients and healthy subjects. Rather, this indicates that the contribution of DES cannot be restricted, in humans, to the ubiquitous concepts of homunculus and somatotopy. DES is a fundamental tool in our attempt to understand the human brain because it represents a unique method for mapping sensorimotor pathways and interfering with the functioning of localized neural populations during the performance of well-defined behavioural tasks.

Cortical plasticity catalyzed by prehabilitation enables extensive resection of brain tumors in eloquent areas

OBJECTIVE The extent of resection is the most important prognostic factor following brain glioma surgery. However, eloquent areas within tumors limit the extent of resection and, thus, critically affect outcomes. The authors hypothesized that presurgical suppression of the eloquent areas within a tumor by continuous cortical electrical stimulation, coupled with appropriate behavioral training ("prehabilitation"), would induce plastic reorganization and enable a more extensive resection. METHODS The authors report on 5 patients harboring gliomas involving eloquent brain areas within tumors as identified on intraoperative stimulation mapping. A grid of electrodes was placed over the residual tumor, and continuous cortical electrical stimulation was targeted to the functional areas. The stimulation intensity was adjusted daily to provoke a mild functional impairment while the function was intensively trained. RESULTS The stimulation intensity required to impair function increased progressively in all patients, and all underwent another operation a mean of 33.6 days later (range 27-37 days), when the maximal stimulation voltage in all active contacts induced no functional deficit. In all cases, a substantially more extensive resection of the tumor was possible. Intraoperative mapping and functional MRI demonstrated a plastic reorganization, and most previously demonstrated eloquent areas within the tumor were silent, while there was new functional activation of brain areas in the same region or toward the contralateral hemisphere. CONCLUSIONS Prehabilitation with continuous cortical electrical stimulation and appropriate behavioral training prior to surgery in patients with WHO Grade II and III gliomas affecting eloquent areas accelerate plastic changes. This can help maximize tumor resection and, thus, improve survival while maintaining function.

Mir-21-Sox2 Axis Delineates Glioblastoma Subtypes with Prognostic Impact

Glioblastoma (GBM) is the most aggressive human brain tumor. Although several molecular subtypes of GBM are recognized, a robust molecular prognostic marker has yet to be identified. Here, we report that the stemness regulator Sox2 is a new, clinically important target of microRNA-21 (miR-21) in GBM, with implications for prognosis. Using the MiR-21-Sox2 regulatory axis, approximately half of all GBM tumors present in the Cancer Genome Atlas (TCGA) and in-house patient databases can be mathematically classified into high miR-21/low Sox2 (Class A) or low miR-21/high Sox2 (Class B) subtypes. This classification reflects phenotypically and molecularly distinct characteristics and is not captured by existing classifications. Supporting the distinct nature of the subtypes, gene set enrichment analysis of the TCGA dataset predicted that Class A and Class B tumors were significantly involved in immune/inflammatory response and in chromosome organization and nervous system development, respectively. Patients with Class B tumors had longer overall survival than those with Class A tumors. Analysis of both databases indicated that the Class A/Class B classification is a better predictor of patient survival than currently used parameters. Further, manipulation of MiR-21-Sox2 levels in orthotopic mouse models supported the longer survival of the Class B subtype. The MiR-21-Sox2 association was also found in mouse neural stem cells and in the mouse brain at different developmental stages, suggesting a role in normal development. Therefore, this mechanism-based classification suggests the presence of two distinct populations of GBM patients with distinguishable phenotypic characteristics and clinical outcomes.

SIGNIFICANCE STATEMENT

Molecular profiling-based classification of glioblastoma (GBM) into four subtypes has substantially increased our understanding of the biology of the disease and has pointed to the heterogeneous nature of GBM. However, this classification is not mechanism based and its prognostic value is limited. Here, we identify a new mechanism in GBM (the miR-21-Sox2 axis) that can classify ∼50% of patients into two subtypes with distinct molecular, radiological, and pathological characteristics. Importantly, this classification can predict patient survival better than the currently used parameters. Further, analysis of the miR-21-Sox2 relationship in mouse neural stem cells and in the mouse brain at different developmental stages indicates that miR-21 and Sox2 are predominantly expressed in mutually exclusive patterns, suggesting a role in normal neural development.

In vivo multiphoton tomography and fluorescence lifetime imaging of human brain tumor tissue

High resolution multiphoton tomography and fluorescence lifetime imaging differentiates glioma from adjacent brain in native tissue samples ex vivo. Presently, multiphoton tomography is applied in clinical dermatology and experimentally. We here present the first application of multiphoton and fluorescence lifetime imaging for in vivo imaging on humans during a neurosurgical procedure. We used a MPTflex™ Multiphoton Laser Tomograph (JenLab, Germany). We examined cultured glioma cells in an orthotopic mouse tumor model and native human tissue samples. Finally the multiphoton tomograph was applied to provide optical biopsies during resection of a clinical case of glioblastoma. All tissues imaged by multiphoton tomography were sampled and processed for conventional histopathology. The multiphoton tomograph allowed fluorescence intensity- and fluorescence lifetime imaging with submicron spatial resolution and 200 picosecond temporal resolution. Morphological fluorescence intensity imaging and fluorescence lifetime imaging of tumor-bearing mouse brains and native human tissue samples clearly differentiated tumor and adjacent brain tissue. Intraoperative imaging was found to be technically feasible. Intraoperative image quality was comparable to ex vivo examinations. To our knowledge we here present the first intraoperative application of high resolution multiphoton tomography and fluorescence lifetime imaging of human brain tumors in situ. It allowed in vivo identification and determination of cell density of tumor tissue on a cellular and subcellular level within seconds. The technology shows the potential of rapid intraoperative identification of native glioma tissue without need for tissue processing or staining.

Facing the future of brain tumor clinical research

This edition of CCR Focus provides critical reviews of several important areas in the field, including the application of findings from genomic investigations of brain tumors to improve diagnosis, clinical trial design, and ultimately optimizing individual patient treatment. Another article is a critical review provided by experts in the field that discusses the recent clinical trials using angiogenesis inhibitors, possible explanations for the results, and how to move forward. There is a concise discussion of the application of immunotherapy to brain tumors by key investigators in this field, reflecting the potential opportunities as well as the disease-specific challenges. Finally, leading pediatric brain tumor investigators provide an overview of the field and insights about the recent seminal discoveries in two pediatric brain tumors, supporting the paradigm that laboratory investigations lead to more precise diagnosis, prognosis, and ultimately better treatment. Herein, an overview of the recent advances and challenges in the area of clinical and translational brain tumor research is provided to set the stage for the contributions that follow.

Neurocognitive Function in Newly Diagnosed Low-grade Glioma Patients Undergoing Surgical Resection With Awake Mapping Techniques

BACKGROUND:

Low-grade glioma (LGG) patients have increased life expectancy, so interest is high in the treatments that maximize cognition and quality of life.

OBJECTIVE:

To examine presurgical baseline cognitive deficits in a case series of LGG patients and determine cognitive effects of surgical resection with awake mapping.

METHODS:

We retrospectively assessed neurological deficits, subjective concerns from patient or caregiver, and cognitive deficits at baseline and postsurgery for 22 patients with newly diagnosed LGG who underwent baseline neuropsychological evaluation and magnetic resonance imaging before awake surgical resection with mapping. Twelve of the 22 patients returned for postoperative evaluation approximately 7 months after surgery.

RESULTS:

At baseline, 92% of patients/caregivers reported changes in cognition or mood. Neurological examinations and Montreal Cognitive Assessment Scale scores were largely normal; however, on many tests of memory and language, nearly half of individuals showed deficits. After surgery, 45% had no deficits on neurological examination, whereas 55% had only transient or mild difficulties. Follow-up neuropsychological testing found most performances stable to improved, particularly in language, although some patients showed declines on memory tasks.

CONCLUSION:

Most LGG patients in this series presented with normal neurological examinations and cognitive screening, but showed subjective cognitive and mood concerns and cognitive decline on neuropsychological testing, suggesting the importance of comprehensive evaluation. After awake mapping, language tended to be preserved, but memory demonstrated decline in some patients. These results highlight the importance of establishing a cognitive baseline before surgical resection and further suggest that awake mapping techniques provide reasonable language outcomes in individuals with LGG in eloquent regions.

Use of high-field intraoperative magnetic resonance imaging to enhance the extent of resection of enhancing and nonenhancing gliomas

BACKGROUND

Intraoperative magnetic resonance imaging (IoMRI) is used to improve the extent of resection of brain tumors. Most previous studies evaluating the utility of IoMRI have focused on enhancing tumors.

OBJECTIVE

To report our experience with the use of high-field IoMRI (1.5 T) for both enhancing and nonenhancing gliomas.

METHODS

An institutional review board-approved retrospective review was performed of 102 consecutive glioma patients (104 surgeries, 2010-2012). Pre-, intra-, and postoperative tumor volumes were assessed. Analysis was performed with the use of volumetric T2 images in 43 nonenhancing and 13 minimally enhancing tumors and with postcontrast volumetric magnetization-prepared rapid gradient-echo images in 48 enhancing tumors.

RESULTS

In 58 cases, preoperative imaging showed tumors likely to be amenable to complete resection. Intraoperative electrocorticography was performed in 32 surgeries, and 14 cases resulted in intended subtotal resection of tumors due to involvement of deep functional structures. No further resection (complete resection before IoMRI) was required in 25 surgeries, and IoMRI showed residual tumor in 79 patients. Of these, 25 surgeries did not proceed to further resection (9 due to electrocorticography findings, 14 due to tumor in deep functional areas, and 2 due to surgeon choice). Additional resection that was performed in 54 patients resulted in a final median residual tumor volume of 0.21 mL (0.6%). In 79 patients amenable to complete resection, the intraoperative median residual tumor volume for the T2 group was higher than for the magnetization-prepared rapid gradient-echo group (1.088 mL vs 0.437 mL; P = .049), whereas the postoperative median residual tumor volume was not statistically significantly different between groups.

CONCLUSION

IoMRI enhances the extent of resection, particularly for nonenhancing gliomas.

Resection of supratentorial gliomas: the need to merge microsurgical technical cornerstones with modern functional mapping concepts. An overview

Although surgery is not curative for the majority of intracranial gliomas, radical resection has been demonstrated to influence survival and delay tumor progression. Because gliomas are very frequently located in eloquent or more generally critical areas, surgeons must always balance the maximizing resection with the need to preserve neurological function. In this overview, we tried to summarize the recent literature and our personal experience about (1) the benefits and limits of using preoperative anatomical and functional neuroimaging (anatomical MRI, DTI fiber tracking, and functional MRI), (2) the issues to consider in planning the surgical strategy, (3) the need to thoroughly understand microsurgical techniques that enable a maximal resection (subpial dissection, vascular manipulation, etc.), (4) the importance of individualizing surgical strategy especially in patients with gliomas in eloquent areas (the role of neuropsychological evaluation in redefining eloquent and non-eloquent areas), and (5) how to use intraoperative mapping techniques and understand why and when to use them. Through this paper, the reader should become more familiar with a comprehensive panel of techniques and methodologies but more importantly become aware that these recent technical advances facilitate a conceptual change from classical surgical paradigms toward a more patient-specific approach.

CNS macrophages and peripheral myeloid cells in brain tumours

Primary brain tumours (gliomas) initiate a strong host response and can contain large amounts of immune cells (myeloid cells) such as microglia and tumour-infiltrating macrophages. In gliomas the course of pathology is not only controlled by the genetic make-up of the tumour cells, but also depends on the interplay with myeloid cells in the tumour microenvironment. Especially malignant gliomas such as glioblastoma multiforme (GBM) are notoriously immune-suppressive and it is now evident that GBM cells manipulate myeloid cells to support tumour expansion. The protumorigenic effects of glioma-associated myeloid cells comprise a support for angiogenesis as well as tumour cell invasion, proliferation and survival. Different strategies for inhibiting the pathological functions of myeloid cells in gliomas are explored, and blocking the tropism of microglia/macrophages to gliomas or manipulating the signal transduction pathways for immune cell activation has been successful in pre-clinical models. Hence, myeloid cells are now emerging as a promising target for new adjuvant therapies for gliomas. However, it is also becoming evident that some myeloid-directed glioma therapies may only be beneficial for distinct subclasses of gliomas and that a more cell-type-specific manipulation of either microglia or macrophages may improve therapeutic outcomes.

Through the patient's eyes: an emphasis on patient-centered values in operative decision making in the management of malignant glioma

The Joint Section on Tumors of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons is now in its 30th year. In many ways its growth and development has paralleled neurosurgery and medicine as a whole. This is most evident in our endeavor towards more patient-centered care and focus on quantity and quality of life. As the push towards evidence-based care continues, it is important to ensure that individualized care remains a guiding principle. Conscientious surgeons continue to refine techniques and develop technologies that push the boundaries of surgical efficacy while better defining the risks of surgery and the impacts of surgical complications. This article provides a review of the factors involved in minimizing risk and obtaining maximal outcomes for patients through insightful patient selection and evidence-based surgical decision-making. Herein, we present the philosophy and practice of the Hermelin Brain Tumor Center at the Henry Ford Health System as one type of approach to caring for the patient with a malignant glioma.

Fluorescence-guided surgery and biopsy in gliomas with an exoscope system

Background. The introduction of fluorescence-guided resection allows a better identification of tumor tissue and its more radical resection. We describe our experience with a modified exoscope to detect 5 ALA-induced fluorescence in neuronavigation-guided brain surgery or biopsy of malignant brain tumors. Methods. Thirty-eight patients with a suspected preoperative diagnosis of high-grade astrocytoma were included. We used a neuronavigation device and a high-definition exoscope system with a built-in filter to detect 5-ALA fluorescence in all cases. Thirty patients underwent craniotomy with tumor resection and 8 underwent frameless stereotactic brain biopsy. Results. Histopathological diagnosis confirmed the presence of high-grade gliomas in 34 patients. Total resection was achieved in 23 cases and subtotal in 7. No relevant complications related to the administration of 5-ALA were detected. Conclusions. The use of the exoscope in 5-ALA fluorescence-guided tumor surgery has twofold implications: during brain tumor surgery it can be considered a valuable tool to achieve a more radical resection of the lesion, and when applied to a biopsy of a suspected brain high-grade glioma, it decreases the possibility of a negative biopsy.

The role of laser interstitial thermal therapy in enhancing progression-free survival of difficult-to-access high-grade gliomas: a multicenter study

Surgical extent-of-resection has been shown to have an impact on high-grade glioma (HGG) outcomes; however, complete resection is rarely achievable in difficult-to-access (DTA) tumors. Controlled thermal damage to the tumor may have the same impact in DTA-HGGs. We report our multicenter results of laser interstitial thermal therapy (LITT) in DTA-HGGs. We retrospectively reviewed 34 consecutive DTA-HGG patients (24 glioblastoma, 10 anaplastic) who underwent LITT at Cleveland Clinic, Washington University, and Wake Forest University (May 2011-December 2012) using the NeuroBlate(®) System. The extent of thermal damage was determined using thermal damage threshold (TDT) lines: yellow TDT line (43 °C for 2 min) and blue TDT line (43°C for 10 min). Volumetric analysis was performed to determine the extent-of-coverage of tumor volume by TDT lines. Patient outcomes were evaluated statistically. LITT was delivered as upfront in 19 and delivered as salvage in 16 cases. After 7.2 months of follow-up, 71% of cases demonstrated progression and 34% died. The median overall survival (OS) for the cohort was not reached; however, the 1-year estimate of OS was 68 ± 9%. Median progression-free survival (PFS) was 5.1 months. Thirteen cases who met the following two criteria-(1) <0.05 cm(3) tumor volume not covered by the yellow TDT line and (2) <1.5 cm(3) additional tumor volume not covered by the blue TDT line-had better PFS than the other 21 cases (9.7 vs. 4.6 months; P = 0.02). LITT can be used effectively for treatment of DTA-HGGs. More complete coverage of tumor by TDT lines improves PFS which can be translated as the extent of resection concept for surgery.

Cortical cartography reveals political and physical maps

Advances in functional imaging have provided noninvasive techniques to probe brain organization of multiple constructs including language and memory. Because of high overall rates of agreements with older techniques, including Wada testing and cortical stimulation mapping (CSM), some have proposed that those approaches should be largely abandoned because of their invasiveness, and replaced with noninvasive functional imaging methods. High overall agreement, however, is based largely on concordant language lateralization in series dominated by cases of typical cerebral dominance. Advocating a universal switch from Wada testing and cortical stimulation mapping to functional magnetic resonance imaging (fMRI) or magnetoencephalography (MEG) ignores the differences in specific expertise across epilepsy centers, many of which often have greater skill with one approach rather than the other, and that Wada, CSM, fMRI, and MEG protocols vary across institutions resulting in different outcomes and reliability. Specific patient characteristics also affect whether Wada or CSM might influence surgical management, making it difficult to accept broad recommendations against currently useful clinical tools. Although the development of noninvasive techniques has diminished the frequency of more invasive approaches, advocating their use to replace Wada testing and CSM across all epilepsy surgery programs without consideration of the different skills, protocols, and expertise at any given center site is ill-advised.

Fluorescence-guided surgery in high grade gliomas using an exoscope system

BACKGROUND

Fluorescence-guided microsurgical resections of high-grade gliomas using 5-aminolevulinic acid (5-ALA) is superior to conventional microsurgery. An optical device, usually a modified microscope, is needed for these procedures. However, an exoscope may be implemented for fluorescence techniques. We present the use of an exoscope to perform tumor resection guided by 5-ALA fluorescence in 21 consecutive patients with high-grade glioma and two neuronavigation-guided biopsies.

METHODS

Twenty-three patients underwent operations. Tumor volume and localization were quantified with pre- and postoperative volumetric MRI in non-biopsy cases.

RESULTS

In non-biopsy cases, the age range was 20 to 79 years, with a median of 56 (interquartile range = 45-66). Histological analysis indicated that 14 had glioblastoma multiforme, 2 grade-III oligodendrogliomas and 1 anaplastic astrocytoma, 3 metastases and 1 low-grade astrocytoma. Total resection was achieved in 15 cases; subtotal resection was performed in 5 patients. The result was partial resection in one case. There was no perioperative mortality. The median fluorescence intensity, on a scale of 1-5, was 4.5 in the GBM group (IQR = 4-5), 3 (IQR = 2.5-3.5) in anaplastic glioma, and 2.5 (IQR = 2.25-2.75) for oligodendrogliomas. Of the three metastases, one showed fluorescence level 4. As for the two biopsy cases, one was anaplastic astrocytoma and one glioblastoma multiforme. The samples obtained were fluorescent in both cases.

CONCLUSIONS

An exoscope can be also used for fluorescence-guided surgery with 5-aminolevulinic acid (5-ALA) and neuronavigation-guided biopsy. With an important advantage of low cost, this allows the surgeon to perform collaborative surgeries and adds agility to the procedure.

Management of low-grade gliomas: a review of patient-perceived quality of life and neurocognitive outcome

Low-grade glioma (LGG) comprises nearly 20% of all central nervous system glial tumors, with approximately 2000-3000 patients diagnosed annually in the United States. Because of their infiltrative ability and aggressive nature, the average 10-year survival is 30% when <90% of the tumor is resected. Since the 1970s, prognosis for LGGs has improved significantly. This improvement is primarily attributable to earlier diagnoses via magnetic resonance imaging scanning, increased awareness of the more favorable oligo component, technical advances in intraoperative neurosurgery, and stratification for young age. Using a number of prognostic factors, LGGs have been classified into low-risk and high-risk subgroups. Optimal therapy for patients with low-risk, supratentorial grade II glioma remains a highly controversial issue in the neuro-oncology community. The concerns regarding the toxicity of therapy often outweigh the benefits of delaying tumor progression. The recommendation for observation is made without full prospective understanding of the impact of radiologic tumor progression on the quality of life (QOL), neurocognitive function (NCF), seizure control, and functional status of these patients. We present a review of the current knowledge of the management of LGG with emphasis upon patient-reported outcomes of QOL, NCF, and seizure control. We also discuss current clinical trials with proposals to evaluate QOL, NCF, and seizure control in patients undergoing observation alone after newly diagnosed low-risk LGG or treatment options for those patients in the high-risk group.

Harnessing plasticity for the treatment of neurosurgical disorders: an overview

Plasticity is fundamental to normal central nervous system function and its response to injury. Understanding this adaptive capacity is central to the development of novel surgical approaches to neurologic disease. These innovative interventions offer the promise of maximizing functional recovery for patients by harnessing targeted plasticity. Developing novel therapies will require the unprecedented integration of neuroscience, bioengineering, molecular biology, and physiology. Such synergistic approaches will create therapeutic options for patients previously outside of the scope of neurosurgery, such as those with permanent disability after traumatic brain injury or stroke. In this review, we synthesize the rapidly evolving field of plasticity and explore ways that neurosurgeons may enhance functional recovery in the future. We conclude that understanding plasticity is fundamental to modern neurosurgical education and practice.

Supratentorial gliomas in eloquent areas: which parameters can predict functional outcome and extent of resection?

BACKGROUND

To date, few parameters have been found that can aid in patient selection and surgical strategy for eloquent area gliomas.

AIMS

The aim of the study was to analyze preoperative and intraoperative factors that can predict functional outcome and extent of resection in eloquent area tumors.

PATIENTS AND METHODS

A retrospective analysis was conducted on 60 patients harboring supratentorial gliomas in eloquent areas undergoing awake surgery. The analysis considered clinical, neuroradiologic (morphologic), intraoperative, and postoperative factors. End-points were extent of resection (EOR) as well as functional short- and long-term outcome. Postoperatively, MRI objectively established the EOR. χ(2) analyses were used to evaluate parameters that could be predictive. Multivariate logistic regression analyses were used to evaluate the best combination to predict binary positive outcomes.

RESULTS

In 90% of the cases, subcortical stimulation was positive in the margins of the surgical cavity. Postoperatively, 51% of the patients deteriorated but 90% of the patients regained their preoperative neurological score. Factors negatively affecting EOR were volume, degree of subcortical infiltration, and presence of paresis (P<0.01). Sharp margins and cystic components were more amenable to gross total resection (P<0.01). Contrast enhancement (P<0.02), higher grade (P<0.01), paresis (P<0.01), and residual tumor in the cortex (P<0.02) negatively affected long-term functional outcomes, whereas postoperative deterioration could not be predicted for any factor other than paresis. Subcortical stimulation did not correlate with deterioration, both postoperatively (P<0.08) and at follow-up (P<0.042).

CONCLUSIONS

Biological and morphological factors such as type of margins, volume, preoperative neurological status, cystic components, histology and the type of infiltration into the white matter must be considered when planning intraoperative mapping.

Long-term evaluation of cognition after glioma surgery in eloquent areas

Preservation of cognition is an important outcome measure in eloquent area glioma surgery. Glioma patients may have pre-operative deficits in one or more cognitive domains which could deteriorate post-operatively. It is assumed that these impairments recover within 3 months; some studies however, still detected cognitive decline. Longer follow-up is necessary to elucidate the conclusive effects of surgery. 45 patients with gliomas (low- and high-grade, but without contrast enhancement at diagnosis) in eloquent areas were assessed pre-operatively, 3 months and 1 year post-operatively with a neuropsychological test-protocol. Patients' performance was compared to normal population and between test-moments. Univariate analyses were performed between cognitive change and tumor-characteristics (localization, grade, volume, extent of resection [EOR]) and treatment-related factors (radio-/chemotherapy). Pre- and post-operatively, impairments were found in all cognitive domains; language, memory, attention and executive functions (p < 0.05). Post-operatively, permanent improvement was observed on a memory test (verbal recall: t = -1.931, p = 0.034), whereas deterioration was found on a language test (category fluency: t = 2.517, p = 0.030). Between 3 months and 1 year, patients improved on 2 language tests (naming: t = -2.781, p = 0.026 and letter fluency: t = -1.975, p = 0.047). There was no influence of tumor- or treatment-related factors on cognitive change. The findings underline the importance of cognitive testing at longer term post-operatively, as cognitive recovery took longer than 3 months, especially within the language domain. However, this longitudinal follow-up study showed that glioma surgery is possible without major long-term damage of cognitive functions. Tumor characteristics and EOR are no additional risk factors for cognitive outcome.

Clinical variables serve as prognostic factors in a model for survival from glioblastoma multiforme: an observational study of a cohort of consecutive non-selected patients from a single institution

Background

Although implementation of temozolomide (TMZ) as a part of primary therapy for glioblastoma multiforme (GBM) has resulted in improved patient survival, the disease is still incurable. Previous studies have correlated various parameters to survival, although no single parameter has yet been identified. More studies and new approaches to identify the best and worst performing patients are therefore in great demand.

Methods

This study examined 225 consecutive, non-selected GBM patients with performance status (PS) 0–2 receiving postoperative radiotherapy with concomitant and adjuvant TMZ as primary therapy. At relapse, patients with PS 0–2 were mostly treated by reoperation and/or combination with bevacizumab/irinotecan (BEV/IRI), while a few received TMZ therapy if the recurrence-free period was >6 months.

Results

Median overall survival and time to progression were 14.3 and 8.0 months, respectively. Second-line therapy indicated that reoperation and/or BEV/IRI increased patient survival compared with untreated patients and that BEV/IRI was more effective than reoperation alone. Patient age, ECOG PS, and use of corticosteroid therapy were significantly correlated with patient survival and disease progression on univariate analysis, whereas p53, epidermal growth factor receptor, and O⁶-methylguanine-DNA methyltransferase expression (all detected by immunohistochemistry), tumor size or multifocality, and extent of primary operation were not. A model based on age, ECOG PS, and corticosteroids use was able to predict survival probability for an individual patient.

Conclusion

The survival of RT/TMZ-treated GBM patients can be predicted based on patient age, ECOG PS, and corticosteroid therapy status.

Re-establishing the merits of electrical brain stimulation

During the past decades, direct electrical stimulation (DES) has been a key method not only in determining the organization of brain networks mediating movement, language, and cognition but also in establishing many central concepts of modern neuroscience, such as the electrical nature of neural transmission, the localization of brain functions, and the homuncular arrangement of sensorimotor areas. However, recent criticisms have questioned the utility of DES and argued that data collected with this technique may be flawed and unreliable. As with every other neuroscientific method, DES does have limitations. However, existing evidence argues strongly for its validity and usefulness by demonstrating that DES produces highly specific outcomes at well-defined anatomical sites and significantly minimizes postoperative deficits in brain-damaged patients.

The role of MGMT testing in clinical practice: a report of the association for molecular pathology

Recent advances in modern molecular technologies allow for the examination and measurement of cancer-related genomic changes. The number of molecular tests for evaluation of diagnostic, prognostic, or predictive markers is expected to increase. In recent years, O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation has been firmly established as a biomarker in patients diagnosed with gliomas, for both clinical trials and routine clinical management. Similarly, molecular markers, such as loss of heterozygosity (LOH) for 1p/19q have already demonstrated clinical utility in treatment of oligodendroglial tumors, and others might soon show clinical utility. Furthermore, nonrandom associations are being discovered among MGMT, 1p/19q LOH, isocitrate dehydrogenase (IDH) mutations, and other tumor-specific modifications that could possibly enhance our ability to predict outcome and response to therapy. While pathologists are facing new and more complicated requests for clinical genomic testing, clinicians are challenged with increasing numbers of molecular data coming from molecular pathology and genomic medicine. Both pathologists and oncologists need to understand the clinical utility of molecular tests and test results, including issues of turnaround time, and their impact on the application of targeted treatment regimens. This review summarizes the existing data that support the rationale for MGMT promoter methylation testing and possibly other molecular testing in clinically defined glioma subtypes. Various molecular testing platforms for evaluation of MGMT methylation status are also discussed.

Treatment options in newly diagnosed glioblastoma

OPINION STATEMENT

Regardless of MGMT status, standard of care for a patient with newly diagnosed glioblastoma (GBM), age ≤70 years, and adequate functional status is radiation and concurrent temozolomide followed by adjuvant temozolomide. For elderly patients, recent studies have suggested that standard radiation, hypofractionated radiation, or single agent temozolomide are acceptable treatment options. Randomized phase III studies of bevacizumab in combination with radiation and temozolomide for newly diagnosed GBM have completed accrual. Preliminary results reveal a clear progression-free survival benefit. Overall survival appears unchanged although follow-up has not fully matured and cross-over to bevacizumab upon progression among control patients may limit definitive conclusions. Although bevacizumab in the upfront setting may be considered for a subset of patients, it should not be used routinely in newly diagnosed patients until final results are available. Clinical trials evaluating promising therapeutics given in combination with standard temozolomide chemoradiation are critically needed.

Low-grade astrocytomas: the prognostic value of fibrillary, gemistocytic, and protoplasmic tumor histology

OBJECT

Low-grade astrocytomas are slow-growing, infiltrative gliomas that over time may progress into more malignant tumors. Various factors have been shown to affect the time to progression and overall survival including age, performance status, tumor size, and the extent of resection. However, more recently it has been suggested that histological subtypes (fibrillary, protoplasmic, and gemistocytic) may impact patient outcome. In this study the authors have performed a large comparative population-based analysis to examine the characteristics and survival of patients with the various subtypes of WHO Grade II astrocytomas.

METHODS

Patients diagnosed with fibrillary, protoplasmic, and gemistocytic astrocytomas were identified through the Surveillance, Epidemiology, and End Results (SEER) database. The chi-square test and Student t-test were used to evaluate differences in patient and treatment characteristics between astrocytoma subtypes. Kaplan-Meier analysis was used to assess overall survival, and the log-rank test was used to evaluate the differences between survival curves. Univariate and multivariate analyses were also performed to determine the effect of various patient, tumor, and treatment variables on overall survival.

RESULTS

A total of 500 cases were included in the analysis, consisting of 326 fibrillary (65.2%), 29 protoplasmic (5.8%), and 145 gemistocytic (29%) variants. Gemistocytic astrocytomas presented at a significantly older age than the fibrillary variant (46.8 vs 37.7 years, p < 0.0001), with protoplasmic and fibrillary subtypes having a similar age. Although protoplasmic and fibrillary variants underwent radiotherapy at similar rates, gemistocytic tumors more frequently received radiotherapy (p = 0.0001). Univariate analysis revealed older age, larger tumor size, and the use of radiotherapy to be poor prognostic factors, with resection being associated with improved survival. The gemistocytic subtype (hazard ratio [HR] 1.62 [95% CI 1.27-2.07], p = 0.0001) also resulted in significantly worse survival than fibrillary tumors. Bivariate analyses demonstrated that older age, the use of radiotherapy, and resection significantly influenced median survival. Tumor subtype also affected median survival; patients who harbored gemistocytic tumors experienced less than half the median survival of fibrillary and protoplasmic tumors (38 vs 82 months, p = 0.0003). Multivariate analysis revealed increasing age (HR 1.05 [95% CI 1.04-1.05], p < 0.0001), larger tumor size (HR 1.02 [95% CI 1.01-1.03], p = 0.0002), and the use of resection (HR 0.70 [95% CI 0.52-0.94], p = 0.018) to be independent predictors of survival. Examination of tumor subtype revealed that the gemistocytic variant (HR 1.30 [95% CI 0.98-1.74], p = 0.074) was associated with worse patient survival than fibrillary tumors, although this only approached significance. The protoplasmic subtype did not affect overall survival (p = 0.33).

CONCLUSIONS

Gemistocytic tumor histology was associated with worse survival than fibrillary and protoplasmic astrocytomas. As protoplasmic astrocytomas have a survival similar to fibrillary tumors, there may be limited utility to the identification of this rare variant. However, increased attention should be paid to the presence of gemistocytes in low-grade gliomas as this is associated with shorter time to progression, increased malignant transformation, and reduced overall survival.

Understanding high grade glioma: molecular mechanism, therapy and comprehensive management

High-grade gliomas (HGGs) account for the vast majority of all gliomas, including glioblastoma (World Health Organization (WHO) grade IV) and anaplasticgliomas (WHO grade III). Despite tremendous efforts in developing multimodal treatments, the overall prognosis remains poor; however, survival time varies considerably between patients. The nature of diffuse permeation into surrounding brain parenchyma poses dilemma for neurosurgeons between extensive surgical resection to eliminate as much as tumor cells as possible and adverse effects associated with brain function. Heterogeneity in both cytology and gene expression makes it difficult to coordinate an effective therapy which works for every patient. This article reviews recent advancements in the molecular mechanism, multimodal treatment and clinical management, and the updated view on the biomarkers in patients with HGG, both in primary and recurrent setting, with an emphasis on targeted therapies tailored to the patient.