Surgical resection versus watchful waiting in low-grade gliomas

Impact of 1p/19q codeletion status on extent of resection in WHO grade II glioma: Insights from a national cancer registry

OBJECTIVE

Traditionally, extent of resection (EOR) has been seen as a surgical parameter that can predict survival outcomes of surgically managed WHO grade II gliomas. The aim of this study was to evaluate if such an influence was potentially affected by 1p/19q codeletion status based on a national cancer registry.

PATIENT AND METHODS

All adults diagnosed with grade II gliomas between the years 2004 to 2014 were queried from the National Cancer Database (NCDB). The population was then divided based on 1p/19q codeletion status, and then Kaplan-Meier, univariate and multivariate Cox regression analyses were utilized to evaluate the prognostic effect of EOR.

RESULTS

In total, 1,498 grade II gliomas satisfied inclusion for analysis, with the 1p/19q non-codeleted in 705 (47%) cases, and codeletion in 793 (53%) cases. When the cohort was divided based on codeletion status, Kaplan-Meier modelling and univariate regression analyses indicated that gross total resection (GTR) was significantly associated with greater 5-overall survival (OS) in both 1p/19q non-codeleted and codeletion groups. Upon multivariate analysis which incorporated adjuvant therapy status, the significance of GTR was only retained in the 1p/19q non-codeletion group after post-hoc adjustment.

CONCLUSION

Our findings indicate that the survival impact of GTR in grade II gliomas may be affected by 1p/19q codeletion status within the first five years after surgery based on overall survival. Therefore, molecular diagnostics have potential clinical application in surgery outcomes, and validation of the reported findings will assist in surgical planning if such an association can be thoroughly established.

The landscape of postsurgical recurrence patterns in diffuse low-grade gliomas

Early and maximal safe surgical resection optionally followed by adjuvant treatment is currently recommended in diffuse low-grade glioma (DLGG). Although this management delays malignant transformation (MT), recurrence will most often occur. Because this relapse usually arises locally, reoperation can be considered, with possible further chemotherapy/radiotherapy. However, due to a prolonged overall survival, a large spectrum of unusual recurrence patterns begins to emerge during long-term follow-up, beyond the classical slow and local tumor re-growth. We review various atypical patterns of DLGG relapse, we discuss their pathophysiological mechanisms and how to adapt the treatment(s). Those patterns include very diffuse, ipsi- or bilateral gliomatosis-like progression, multicentric recurrence with emergence of remote low-grade or high-grade glioma, leptomeningeal dissemination, acute (early or delayed) local MT or bulky relapse into the operating cavity. This landscape of recurrence patterns may allow physicians to elaborate new tailored therapeutic strategies and scientists to develop original hypotheses for basic research.

Huge heterogeneity in survival in a subset of adult patients with resected, wild-type isocitrate dehydrogenase status, WHO grade II astrocytomas

OBJECTIVE

World Health Organization grade II gliomas are infiltrating tumors that inexorably progress to a higher grade of malignancy. However, the time to malignant transformation is quite unpredictable at the individual patient level. A wild-type isocitrate dehydrogenase (IDH-wt) molecular profile has been reported as a poor prognostic factor, with more rapid progression and a shorter survival compared with IDH-mutant tumors. Here, the oncological outcomes of a series of adult patients with IDH-wt, diffuse, WHO grade II astrocytomas (AII) who underwent resection without early adjuvant therapy were investigated.

METHODS

A retrospective review of patients extracted from a prospective database who underwent resection between 2007 and 2013 for histopathologically confirmed, IDH-wt, non-1p19q codeleted AII was performed. All patients had a minimum follow-up period of 2 years. Information regarding clinical, radiographic, and surgical results and survival were collected and analyzed.

RESULTS

Thirty-one consecutive patients (18 men and 13 women, median age 39.6 years) were included in this study. The preoperative median tumor volume was 54 cm3 (range 3.5-180 cm3). The median growth rate, measured as the velocity of diametric expansion, was 2.45 mm/year. The median residual volume after surgery was 4.2 cm3 (range 0-30 cm3) with a median volumetric extent of resection of 93.97% (8 patients had a total or supratotal resection). No patient experienced permanent neurological deficits after surgery, and all patients resumed a normal life. No immediate postoperative chemotherapy or radiation therapy was given. The median clinical follow-up duration from diagnosis was 74 months (range 27-157 months). In this follow-up period, 18 patients received delayed chemotherapy and/or radiotherapy for tumor progression. Five patients (16%) died at a median time from radiological diagnosis of 3.5 years (range 2.6-4.5 years). Survival from diagnosis was 77.27% at 5 years. None of the 21 patients with a long-term follow-up greater than 5 years have died. There were no significant differences between the clinical, radiological, or molecular characteristics of the survivors relative to the patients who died.

CONCLUSIONS

Huge heterogeneity in the survival data for a subset of 31 patients with resected IDH-wt AII tumors was observed. These findings suggest that IDH mutation status alone is not sufficient to predict risk of malignant transformation and survival at the individual level. Therefore, the therapeutic management of AII tumors, in particular the decision to administer early adjuvant chemotherapy and/or radiation therapy following surgery, should not solely rely on routine molecular markers.

Controversies in the Therapy of Low-Grade Gliomas

OPINION STATEMENT

In the context of the new WHO classification system, all low-grade gliomas must have an IDH mutation, with or without 1p/19q codeletion. Upon discovery of the tumor, maximal safe surgical resection is the most appropriate first step due to the current inability to differentiate between IDH mutant and IDH wild-type tumors by imaging alone. In the postoperative setting, based on the synthesis and interpretation of the available data, we recommend utilizing conventional radiation therapy and PCV in all high-risk-low-grade gliomas. For patients felt to be in a low risk category, we recommend maintaining a low threshold to initiate treatment. In the setting of tumor recurrence, consideration of all treatment options is reasonable, but treatment with alkylator therapy has the strongest supporting data.

Neurosurgical patterns of care for diffuse low-grade gliomas in Sweden between 2005 and 2015

BACKGROUND

In the last decade, increasing evidence has evolved for early and maximal safe resection of diffuse low-grade gliomas (LGGs) regarding survival. However, changes in clinical practice are known to occur slowly and we do not know if the scientific evidence has yet resulted in changes in neurosurgical patterns of care.

METHODS

The Swedish Brain Tumor Registry was used to identify all patients with a first-time histopathological diagnosis of LGG between 2005 and 2015. For analysis of surgical treatment patterns, we subdivided assessed time periods into 2005-2008, 2009-2012, and 2013-2015. Population-based data on patient and disease characteristics, surgical management, and outcomes were extracted.

RESULTS

A total of 548 patients with diffuse World Health Organization grade II gliomas were identified: 142 diagnosed during 2005-2008, 244 during 2009-2012, and 162 during 2013-2015. Resection as opposed to biopsy was performed in 64.3% during 2005-2008, 74.2% during 2009-2012, and 74.1% during 2013-2015 (P = .08). There was no difference among the 3 periods regarding overall survival (P = .11). However, post hoc analysis of data from the 4 (out of 6) centers that covered all 3 time periods demonstrated a resection rate of 64.3% during 2005-2008, 77.4% during 2009-2012, and 75.4% during 2013-2015 (P = .02) and longer survival of patients diagnosed 2009 and onward (P = .04).

CONCLUSION

In this nationwide, population-based study we observed a shift over time in favor of LGG resection. Further, a positive correlation between the more active surgical strategy and longer survival is shown, although no causality can be claimed because of possible confounding factors.

The impact of surgery in molecularly defined low-grade glioma: an integrated clinical, radiological, and molecular analysis

Background

Extensive resections in low-grade glioma (LGG) are associated with improved overall survival (OS). However, World Health Organization (WHO) classification of gliomas has been completely revised and is now predominantly based on molecular criteria. This requires reevaluation of the impact of surgery in molecularly defined LGG subtypes.

Methods

We included 228 adults who underwent surgery since 2003 for a supratentorial LGG. Pre- and postoperative tumor volumes were assessed with semiautomatic software on T2-weighted images. Targeted next-generation sequencing was used to classify samples according to current WHO classification. Impact of postoperative volume on OS, corrected for molecular profile, was assessed using a Cox proportional hazards model.

Results

Median follow-up was 5.79 years. In 39 (17.1%) histopathologically classified gliomas, the subtype was revised after molecular analysis. Complete resection was achieved in 35 patients (15.4%), and in 54 patients (23.7%) only small residue (0.1-5.0 cm3) remained. In multivariable analysis, postoperative volume was associated with OS, with a hazard ratio of 1.01 (95% CI: 1.002-1.02; P = 0.016) per cm3 increase in volume. The impact of postoperative volume was particularly strong in isocitrate dehydrogenase (IDH) mutated astrocytoma patients, where even very small postoperative volumes (0.1-5.0 cm) already negatively affected OS.

Conclusion

Our data provide the necessary reevaluation of the impact of surgery in molecularly defined LGG and support maximal resection as first-line treatment for molecularly defined LGG. Importantly, in IDH mutated astrocytoma, even small postoperative volumes have negative impact on OS, which argues for a second-look operation in this subtype to remove minor residues if safely possible.

Extent of Resection Versus Molecular Classification: What Matters When?

For malignant gliomas, the survival benefit of new combination therapies after surgical resection is measured in weeks to months. In contrast, optimizing treatment for low-grade gliomas can potentially provide additional years of life. The relatively indolent but not benign clinical course provides the opportunity for clinicians and scientists to focus not only on the duration of survival, but also to maximize quality of life. Ideal management of low-grade gliomas among the most important yet paradoxically most neglected subjects in neuro-oncology. This article examines the molecular underpinnings of these tumors and evaluates the role of extensive surgery in maximizing outcomes.

Diffuse Low-Grade Glioma - Changing Concepts in Diagnosis and Management: A Review

Though diffuse low-grade gliomas (dLGGs) represent only 15% of gliomas, they have been receiving increasing attention in the past decade. Significant advances in knowledge of the natural history and clinical diversity have been documented, and an improved pathological classification of gliomas that integrates histological features with molecular markers has been issued by the WHO. Advances in the radiological assessment of dLGG, particularly new magnetic resonance imaging scanning sequences, allow improved diagnostic and prognostic information. The management paradigms are evolving from “wait and watch” of the past to more active interventional therapy to obviate the risk of malignant transformation. New surgical technologies allow more aggressive surgical resections with a reduction of morbidity. Many reports suggest the association of gross total resection with longer overall survival and progression-free survival in addition to better seizure control. The literature also shows the use of chemotherapeutics and radiation therapy as important adjuncts to surgery. The goals of management have has been increasing survival with increasing stress on quality of life. Our review highlights the recent advances in the molecular diagnosis and management of dLGG with trends toward multidisciplinary and multimodality management of dLGG with an aim to surgically resect the primary disease, followed by chemoradiation in cases of progressive or recurrent disease.

Advanced Ultrasound Imaging in Glioma Surgery: Beyond Gray-Scale B-mode

Introduction: Glioma surgery is aimed at obtaining maximal safe tumor resection while preserving or improving patient's neurological status. For this reason, there is growing interest for intra-operative imaging in neuro-oncological surgery. Intra-operative ultrasound (ioUS) provides the surgeon with real-time, anatomical and functional information. Despite this, in neurosurgery ioUS mainly relies only on gray-scale brightness mode (B-mode). Many other ultrasound imaging modalities, such as Fusion Imaging with pre-operative acquired magnetic resonance imaging (MRI), Doppler modes, Contrast Enhanced Ultrasound (CEUS), and elastosonography have been developed and have been extensively used in other organs. Although these modalities offer valuable real-time intra-operative information, so far their usage during neurosurgical procedures is still limited.

Purpose: To present an US-based multimodal approach for image-guidance in glioma surgery, highlighting the different features of advanced US modalities: fusion imaging with pre-operative acquired MRI for Virtual Navigation, B-mode, Doppler (power-, color-, spectral-), CEUS, and elastosonography.

Methods: We describe, in a step-by-step fashion, the applications of the most relevant advanced US modalities during different stages of surgery and their implications for surgical decision-making. Each US modality is illustrated from a technical standpoint and its application during glioma surgery is discussed.

Results: B-mode offers dynamic morphological information, which can be further implemented with fusion imaging to improve image understanding and orientation. Doppler imaging permits to evaluate anatomy and function of the vascular tree. CEUS allows to perform a real-time angiosonography, providing valuable information in regards of parenchyma and tumor vascularization and perfusion. This facilitates tumor detection and surgical strategy, also allowing to characterize tumor grade and to identify residual tumor. Elastosonography is a promising tool able to better define tumor margins, parenchymal infiltration, tumor consistency and permitting differentiation of high grade and low grade lesions.

Conclusions: Multimodal ioUS represents a valuable tool for glioma surgery being highly informative, rapid, repeatable, and real-time. It is able to differentiate low grade from high grade tumors and to provide the surgeon with relevant information for surgical decision-making. ioUS could be integrated with other intra-operative imaging and functional approaches in a synergistic manner to offer the best image guidance for each patient.

Surgical management of lower-grade glioma in the spotlight of the 2016 WHO classification system

PURPOSE

According to the 2016 WHO classification lower-grade gliomas consist of three groups: IDH-mutated and 1p/19q co-deleted, IDH-mutated and IDH-wildtype tumors. The aim of this study was to evaluate the impact of surgical therapy for lower-grade gliomas with a particular focus on the molecular subgroups.

METHODS

This is a bi-centric retrospective analysis including 299 patients, who underwent treatment for lower-grade glioma between 1990 and 2016. All tumors were re-classified according to the 2016 WHO classification. Data concerning baseline and tumor characteristics, overall survival, different treatment modalities and functional outcome were analyzed.

RESULTS

A total of 112 (37.5%) patients with IDH-mutation and 1p/19q co-deletetion, 86 (28.8%) patients with IDH-mutation and 101 (33.8%) patients with IDH-wildtype tumors were identified. The median overall survival (mOS) differed significantly between the groups (p < 0.001). Surgical resection was performed in 226 patients and showed significantly improved mOS compared to the biopsy group (p = 0.001). Gross total resection (GTR) was associated with better survival (p = 0.007) in the whole cohort as well as in the IDH-mutated and IDH-wildtype groups compared to partial resection or biopsy. IDH-wildtype patients presented a significant survival benefit after combined radio-chemotherapy compared to radio- or chemotherapy alone (p = 0.02). Good clinical status (NANO) was associated with longer OS (p = 0.001).

CONCLUSION

The impact of surgical treatment on the outcome of lower-grade gliomas depends to a great extent on the molecular subtype of the tumors. Patients with more aggressive tumors (IDH-wildtype) seem to profit from more intensive treatment like GTR, multiple resections and combined radio-/chemotherapy.

Effects of surgery on neurocognitive function in patients with glioma: a meta-analysis of immediate post-operative and long-term follow-up neurocognitive outcomes

PURPOSE

This study aims to identify the neuropsychological tests commonly used for assessment in each neurocognitive domain, and quantify the post-operative changes in neurocognitive function in the immediate post-operation and follow-up.

METHODS

With the use of the PubMed, a comprehensive search of the English literature was performed following PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. There were 1021 publications identified for screening. Standardized mean differences (SMD) in neuropsychological task performance were calculated both for immediate post-operation (up to 1 week) and follow-up (up to 6 months).

RESULTS

Out of 12 studies which met the inclusion criteria, 11 studies were analyzed in this meta-analysis, with a total of 313 patients (age range 18-82, 50% males) with intracranial gliomas (45% high-grade, 55% low-grade). Complex attention, language and executive function were the most frequently tested neurocognitive domains. Surgery had a positive impact in the domains of complex attention, language, learning and memory tasks in the immediate post-operative period and sustained improvement at follow-up. In contrast, surgery was found to negatively impact performance for executive function in the immediate post-operative period with sustained decline in performance in the long term.

CONCLUSIONS

This meta-analysis suggests that surgery for glioma confers a benefit for the domains of complex attention, language, learning and memory, while negatively affecting executive function, in the periods immediately after surgery and at 6 months follow-up. In addition, awake surgery seemed to confer a beneficial effect on neurocognitive functions. Future research should attempt to standardize a battery of neuropsychological tests for patients undergoing surgical resection for glioma, perhaps with a particular focus on executive function.

Higher-Order Surgical Questions for Diffuse Low-Grade Gliomas: Supramaximal Resection, Neuroplasticity, and Screening

Diffuse low-grade glioma (DLGG) is a brain neoplasm that migrates within the connectome and that becomes malignant if left untreated. Early and maximal safe surgical resection by means of awake mapping enables a significant improvement of survival and quality of life. Supramaximal functional-based resection seems to prevent DLGG malignant transformation. Neuroplasticity is helpful to remove DLGG in eloquent areas. When radical excision cannot be achieved due to invasion of critical neural networks, cerebral remapping over time may lead to a reoperation with an optimized resection. To discover and treat DLGG earlier, a screening in the general population should be considered.

Magnetic Resonance Imaging-Based Screening for Asymptomatic Brain Tumors: A Review

Brain tumors comprise 2% of all cancers but are disproportionately responsible for cancer-related deaths. The 5-year survival rate of glioblastoma, the most common form of malignant brain tumor, is only 4.7%, and the overall 5-year survival rate for any brain tumor is 34.4%. In light of the generally poor clinical outcomes associated with these malignancies, there has been interest in the concept of brain tumor screening through magnetic resonance imaging. Here, we will provide a general overview of the screening principles and brain tumor epidemiology, then highlight the major studies examining brain tumor prevalence in asymptomatic populations in order to assess the potential benefits and drawbacks of screening for brain tumors. IMPLICATIONS FOR PRACTICE: Magnetic resonance imaging (MRI) screening in healthy asymptomatic adults can detect both early gliomas and other benign central nervous system abnormalities. Further research is needed to determine whether MRI will improve overall morbidity and mortality for the screened populations and make screening a worthwhile endeavor.

Age and surgical outcome of low-grade glioma in Sweden

BACKGROUND

Low-grade gliomas (LGG) are slow-growing primary brain tumors that typically affect young adults. Advanced age is widely recognized as a poor prognostic factor in LGG. The impact of age on postoperative outcome in this patient group has not been systemically studied.

METHODS

We performed a nationwide register-based study with data from the Swedish Brain Tumor Registry (SBTR) for all adults diagnosed with a supratentorial LGG (WHO grade II astrocytoma, oligoastrocytoma, or oligodendroglioma) during 2005-2015. Patient- and tumor-related characteristics, postoperative complications, and survival were compared between three different age groups (18-39 years, 40-59 years, and ≥60 years).

RESULTS

We identified 548 patients; 204 patients (37.2%) aged 18-39 years, 227 patients (41.4%) aged 40-59 years, and 117 patients (21.4%) ≥60 years of age. Unfavorable preoperative prognostic factors (eg, functional status and neurological deficit) were more common with increased age (P < .001). In addition, overall survival was significantly impaired in those 60 years and above (P < .001). We observed a clear dose-response for age with separation of survival curves at 50 years. Biopsy was more common in patients ≥60 years (P < .001). Subgroup analysis of patients with resection revealed a higher amount of postoperative neurological deficits in older patients (P = .029).

CONCLUSION

In general, older patients with LGG have several unfavorable prognostic factors compared with younger patients but seem to tolerate surgery in a comparable fashion. However, more neurological deficits were observed following resections in elderly. Our data further support a cutoff at 50 years rather than 40 years for selection of high-risk patients.

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.

Paradoxes of evidence-based medicine in lower-grade glioma: To treat the tumor or the patient?

Brain lower-grade gliomas (LGG) usually occur in young adults who enjoy an active life. This tumor has a high risk of malignant transformation resulting in neurologic deterioration and finally death. Early and multistage therapeutic management can increase survival over 10 years. Preservation of functional neural networks and quality of life is crucial. In the era of evidence-based medicine, the issues discussed are those associated with the design, analysis, and clinical application of randomized controlled trials (RCTs) for LGG. RCTs should take account of the following: considerable variability in the natural course of LGG; limited prognostic value of molecular biology at the individual level; large variability of brain organization across patients; technical and conceptual progress of therapies over years; combination or repetition of iterative treatments, taken as a whole and not only in isolation; and long-term consequences on oncologic and functional outcomes. As it is difficult to translate the results of an RCT into benefits for a unique patient with LGG, personalized decisions must be made by considering the tumor behavior, individual pattern of neuroplasticity, and patient needs, and not by administrating a standardized protocol exclusively based on an RCT.

Proton therapy for low-grade gliomas in adults: A systematic review

For adult patients with diffuse low-grade glioma (LGG) proton therapy is an emerging radiotherapy modality. The number of proton facilities is rapidly increasing. However, there is a shortage of published data concerning the clinical effectiveness compared to photon radiotherapy and potential proton-specific toxicity. This study aimed to systematically review and summarize the relevant literature on proton therapy for adult LGG patients, including dosimetric comparisons, the type and frequency of acute and long-term toxicity and the clinical effectiveness. A systematic search was performed in several medical databases and 601 articles were screened for relevance. Nine articles were deemed eligible for in-depth analysis using a standardized data collection form by two independent researchers. Proton treatment plans compared favorably to photon-plans regarding dose to uninvolved neural tissue. Fatigue (27-100%), alopecia (37-85%), local erythema (78-85%) and headache (27-75%) were among the most common acute toxicities. One study reported no significant long-term cognitive impairments. Limited data was available on long-term survival. One study reported a 5-year overall survival of 84% and 5-year progression-free survival of 40%. We conclude that published data from clinical studies using proton therapy for adults with LGG are scarce. As the technique becomes more available, controlled clinical studies are urgently warranted to determine if the potential benefits based on comparative treatment planning translate into clinical benefits.

Primary brain tumours in adults

Primary CNS tumours refer to a heterogeneous group of tumours arising from cells within the CNS, and can be benign or malignant. Malignant primary brain tumours remain among the most difficult cancers to treat, with a 5 year overall survival no greater than 35%. The most common malignant primary brain tumours in adults are gliomas. Recent advances in molecular biology have improved understanding of glioma pathogenesis, and several clinically significant genetic alterations have been described. A number of these (IDH, 1p/19q codeletion, H3 Lys27Met, and RELA-fusion) are now combined with histology in the revised 2016 WHO classification of CNS tumours. It is likely that understanding such molecular alterations will contribute to the diagnosis, grading, and treatment of brain tumours. This progress in genomics, along with significant advances in cancer and CNS immunology, has defined a new era in neuro-oncology and holds promise for diagntic and therapeutic improvement. The challenge at present is to translate these advances into effective treatments. Current efforts are focused on developing molecular targeted therapies, immunotherapies, gene therapies, and novel drug-delivery technologies. Results with single-agent therapies have been disappointing so far, and combination therapies seem to be required to achieve a broad and durable antitumour response. Biomarker-targeted clinical trials could improve efficiencies of therapeutic development.

Supratotal Resection of Diffuse Frontal Lower Grade Gliomas with Awake Brain Mapping, Preserving Motor, Language, and Neurocognitive Functions

OBJECTIVE

Extended margin tumor resection beyond the abnormal area detected by magnetic resonance imaging, defined as supratotal resection, could improve the outcomes of patients with lower grade gliomas (LGGs). The aim of the present study was to assess the surgical outcomes of awake brain mapping to achieve supratotal resection with determination of the normal brain tissue boundaries beyond the tumor of frontal LGGs, in both dominant and nondominant hemispheres.

METHODS

We analyzed the data from 9 patients with diffuse frontal LGGs who had undergone supratotal resection with awake surgery from January 2016 to November 2017.

RESULTS

The frontal aslant tract was identified as the functional boundary in 4 of 5 left frontal tumor cases (80%). Working memory impairments during dorsolateral prefrontal cortex stimulation with digit span and/or visual N-back tasks were detected in all 4 patients (100%) with right-frontal tumor. The neurocognitive outcomes were significantly improved after surgery, as shown by the mean Wechsler adult intelligence scale III scores for verbal intelligence quotient (P = 0.04) and verbal comprehension (P = 0.03) and the mean Wechsler memory scale-revised scores for generalized memory (P = 0.04) and delayed recall (P = 0.04).

CONCLUSIONS

The results of the present study have provided evidence that awake mapping can enable the preservation of higher neurocognitive function, including working memory and spatial cognition in patients with nondominant right frontal tumors. Despite the small number of cases, our findings suggest the surgical benefit of awake surgery for supratotal resection of diffuse frontal LGGs.

Fluorescence-guidance in non-Gadolinium enhancing, but FET-PET positive gliomas

OBJECTIVES

We report on five patients with gadolinium-negative (non-enhancing magnetic resonance imaging-MRI) but ¹⁸F-fluoroethyl tyrosine positron-emission tomography (FET-PET) positive glioma (NEG) undergoing surgery under fluorescence-guidance with fluorescein sodium 10% (FL, Alkon, Germany) in combination with a dedicated light filter (YELLOW 560 nm, Carl Zeiss Meditec, Germany).

PATIENTS AND METHOD

Since 2017, five patients (3 female, 2 male; mean age 45.4 years) underwent fluorescence-guided surgery for supratentorial, intracerebral lesions which showed no contrast-enhancement in the preoperative MRI but were, however, strongly suspicious for gliomas. Accordingly, all patients received a preoperative FET-PET scan and detailed histopathological workup was performed. After giving written informed consent, all patients received 5 mg/kg of FL at the induction of anesthesia. Surgery was conducted under white light and under the YELLOW 560 nm filter. We reviewed the surgical protocols, navigational storage and the image databases of our surgical microscopes for evidence of intraoperative fluorescence that corresponded to the FET-PET positive area.

RESULTS

In all patients we found distinct accordances between the FET-PET positive areas and the fluorescing regions within the targeted lesions. Histopathological workup of the fluorescent tissue revealed anaplastic oligodendroglioma, IDH-mutant and 1p/19-codeleted (WHO grade III) (n = 2), anaplastic astrocytoma, IDH-mutant (WHO grade III) (n = 1), oligodendroglioma, IDH-mutant and 1p/19q-codeleted (WHO grade II) (n = 1) and pilocytic astrocytoma (WHO grade I) (n = 1). No adverse events were noted.

DISCUSSION AND CONCLUSION

Despite the lack of gadolinium-enhancement in the preoperative MRI, all patients intravenously received FL to guide resection. Irrespective of the final grading, FL was extremely helpful in detecting the lesions and in identifying their border zones. In selected patients with NEG, but strong metabolic activity according to the FET-PET, FL may significantly increase the accuracy of surgery.

The role of clinical and molecular factors in low-grade gliomas: what is their impact on survival?

AIM

To evaluate relevance of clinical and molecular factors in adult low-grade gliomas (LGG) and to correlate with survival.

METHODS

We reviewed records from adult LGG patients from 1991 to 2015 who received surgery and had sufficient tissue to molecular biomarkers characterization.

RESULTS

213 consecutive LGG patients were included: 17.4% were low-risk, according to Radiation Therapy Oncology Group (RTOG) risk assessment. IDH 1/2 mutation, 1p/19q co-deletion, MGMT methylation were found in 93, 50.8 and 65.3% of patients. Median follow-up was 98.3 months. In univariate analysis, overall survival was influenced by extent of resection (p = 0.011), IDH mutation (p < 0.001), 1p/19q co-deletion (p = 0.015) and MGMT methylation (p = 0.013). In multivariate analysis, RTOG clinical risk (p = 0.006), IDH mutation (p < 0.001) and 1p/19q co-deletion (p = 0.035) correlated with overall survival. RTOG clinical risk (p = 0.006), IDH mutation (p < 0.001) and 1p/19q co-deletion (p = 0.035) correlated with overall survival.

CONCLUSION

Both clinical and molecular factors are essential to determine prognosis and treatment strategies.

Grade II and III Oligodendroglioma and Astrocytoma

In the 2016 WHO classification of diffuse glioma, the diagnosis of an (anaplastic) oligodendroglioma requires the presence of both an IDH mutation (mt) and 1p/19q codeletion, whereas (anaplastic) astrocytoma are divided in IDH wild-type and IDHmt tumors. Standard of care for grade II and III glioma consists of resection. For patients with tumors that require postoperative treatment, radiotherapy and chemotherapy are recommended. Trials in newly diagnosed grade II and III glioma have shown survival benefit of the addition of chemotherapy to radiotherapy compared with initial treatment with radiotherapy alone; both temozolomide and PCV have been shown to improve survival.

Post-surgical effects on language in patients with presumed low-grade glioma

OBJECTIVES

Low-grade glioma (LGG) is a slow-growing brain tumour often situated in or near areas involved in language and/or cognitive functions. Thus, language impairments due to tumour growth or surgical resection are obvious risks. We aimed to investigate language outcome following surgery in patients with presumed LGG, using a comprehensive and sensitive language assessment.

MATERIALS AND METHODS

Thirty-two consecutive patients with presumed LGG were assessed preoperative, early post-operative, and 3 months post-operative using sensitive tests including lexical retrieval, language comprehension and high-level language. The patients' preoperative language ability was compared with a reference group, but also with performance at post-operative controls. Further, the association between tumour location and language performance pre- and post-operatively was explored.

RESULTS

Before surgery, the patients with presumed LGG performed worse on tests of lexical retrieval when compared to a reference group (BNT: LGG-group median 52, Reference-group median 54, P = .002; Animals: LGG-group mean 21.0, Reference-group mean 25, P = 001; Verbs: LGG-group mean 17.3, Reference-group mean 21.4, P = .001). At early post-operative assessment, we observed a decline in all language tests, whereas at 3 months there was only a decline on a single test of lexical retrieval (Animals: preoperative. median 20, post-op median 14, P = .001). The highest proportion of language impairment was found in the group with a tumour in language-eloquent areas at all time-points.

CONCLUSIONS

Although many patients with a tumour in the left hemisphere deteriorated in their language function directly after surgery, their prognosis for recovery was good.

Glioma surgery with intraoperative mapping-balancing the onco-functional choice

BACKGROUND

Balancing survival versus risk of inducing functional deficits is a challenge when resecting gliomas in or near eloquent areas. Our objectives were to assess deficits prior to and at 6 and 12 months after awake craniotomies with cortical and subcortical mapping in patients with suspected grade 2 gliomas in eloquent areas. We analyzed whether pre- and intraoperative factors were linked to an increased risk of postoperative deficits.

METHOD

Retrospective study of 92 consecutive patients operated between January 2010 and June 2014. All deficits reported by any healthcare professional and KPS-score preoperatively, immediately postoperatively (day 1-10), at 6 months and 12 months, were analyzed.

RESULTS

A decrease in neurological and or cognitive function was common in the first days after surgery, with a significant improvement at 6 months after surgery and further improvement at 12 months. Immediately after surgery, 33% of the patients had severe deficits compared to 2% prior to surgery; this improved to 9% at 6 months and 3% at 12 months. However, at 12 months, 18% of the patients had new or worsened minor or moderate deficits and only 10% had no deficits compared to 39% prior to surgery. There were only minor changes in KPS. None of the recorded pre/intraoperative factors were found significantly to influence the risk of moderate/severe late postoperative deficits.

CONCLUSION

A significant amount of the patients in this study experienced new or worsened neurological and or cognitive deficits during follow-up. We found a higher frequency of deficits than normally reported. This is due to the inclusion of mild deficits, the use of patient-reported data, and our focus on cognitive deficits. Our study indicates that the impact of awake craniotomy with mapping on patient outcome is larger than expected. This in no way negates the use of the technique.

Improving surgical outcome for gliomas with intraoperative mapping

INTRODUCTION

Radical glioma resection improves overall survival, both in low-grade and high-grade glial tumors. However, preservation of the quality of life is also crucial. Areas covered: Due to the diffuse feature of gliomas, which invade the central nervous system, and due to considerable variations of brain organization among patients, an individual cerebral mapping is mandatory to solve the classical dilemma between the oncological and functional issues. Because functional neuroimaging is not reliable enough, intraoperative electrical stimulation, especially in awake patients benefiting from a real-time cognitive monitoring, is the best way to increase the extent of resection while sparing eloquent neural networks. Expert commentary: Here, we propose a paradigmatic shift from image-guided resection to functional mapping-guided resection, based on the study of the dynamic distribution of delocalized cortico-subcortical circuits at the individual level, i.e., the investigation of brain connectomics and neuroplastic potential. This surgical philosophy results in an improvement of both oncological outcomes and quality of life. This highlights the need to reinforce the link between glioma surgery and cognitive neurosciences.

Magnetic resonance perfusion for differentiating low-grade from high-grade gliomas at first presentation

BACKGROUND

Gliomas are the most common primary brain tumour. They are graded using the WHO classification system, with Grade II-IV astrocytomas, oligodendrogliomas and oligoastrocytomas. Low-grade gliomas (LGGs) are WHO Grade II infiltrative brain tumours that typically appear solid and non-enhancing on magnetic resonance imaging (MRI) scans. People with LGG often have little or no neurologic deficit, so may opt for a watch-and-wait-approach over surgical resection, radiotherapy or both, as surgery can result in early neurologic disability. Occasionally, high-grade gliomas (HGGs, WHO Grade III and IV) may have the same MRI appearance as LGGs. Taking a watch-and-wait approach could be detrimental for the patient if the tumour progresses quickly. Advanced imaging techniques are increasingly used in clinical practice to predict the grade of the tumour and to aid clinical decision of when to intervene surgically. One such advanced imaging technique is magnetic resonance (MR) perfusion, which detects abnormal haemodynamic changes related to increased angiogenesis and vascular permeability, or "leakiness" that occur with aggressive tumour histology. These are reflected by changes in cerebral blood volume (CBV) expressed as rCBV (ratio of tumoural CBV to normal appearing white matter CBV) and permeability, measured by K^trans.

OBJECTIVES

To determine the diagnostic test accuracy of MR perfusion for identifying patients with primary solid and non-enhancing LGGs (WHO Grade II) at first presentation in children and adults. In performing the quantitative analysis for this review, patients with LGGs were considered disease positive while patients with HGGs were considered disease negative.To determine what clinical features and methodological features affect the accuracy of MR perfusion.

SEARCH METHODS

Our search strategy used two concepts: (1) glioma and the various histologies of interest, and (2) MR perfusion. We used structured search strategies appropriate for each database searched, which included: MEDLINE (Ovid SP), Embase (Ovid SP), and Web of Science Core Collection (Science Citation Index Expanded and Conference Proceedings Citation Index). The most recent search for this review was run on 9 November 2016.We also identified 'grey literature' from online records of conference proceedings from the American College of Radiology, European Society of Radiology, American Society of Neuroradiology and European Society of Neuroradiology in the last 20 years.

SELECTION CRITERIA

The titles and abstracts from the search results were screened to obtain full-text articles for inclusion or exclusion. We contacted authors to clarify or obtain missing/unpublished data.We included cross-sectional studies that performed dynamic susceptibility (DSC) or dynamic contrast-enhanced (DCE) MR perfusion or both of untreated LGGs and HGGs, and where rCBV and/or K^trans values were reported. We selected participants with solid and non-enhancing gliomas who underwent MR perfusion within two months prior to histological confirmation. We excluded studies on participants who received radiation or chemotherapy before MR perfusion, or those without histologic confirmation.

DATA COLLECTION AND ANALYSIS

Two review authors extracted information on study characteristics and data, and assessed the methodological quality using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. We present a summary of the study characteristics and QUADAS-2 results, and rate studies as good quality when they have low risk of bias in the domains of reference standard of tissue diagnosis and flow and timing between MR perfusion and tissue diagnosis.In the quantitative analysis, LGGs were considered disease positive, while HGGs were disease negative. The sensitivity refers to the proportion of LGGs detected by MR perfusion, and specificity as the proportion of detected HGGs. We constructed two-by-two tables with true positives and false negatives as the number of correctly and incorrectly diagnosed LGG, respectively, while true negatives and false positives are the number of correctly and incorrectly diagnosed HGG, respectively.Meta-analysis was performed on studies with two-by-two tables, with further sensitivity analysis using good quality studies. Limited data precluded regression analysis to explore heterogeneity but subgroup analysis was performed on tumour histology groups.

MAIN RESULTS

Seven studies with small sample sizes (4 to 48) met our inclusion criteria. These were mostly conducted in university hospitals and mostly recruited adult patients. All studies performed DSC MR perfusion and described heterogeneous acquisition and post-processing methods. Only one study performed DCE MR perfusion, precluding quantitative analysis.Using patient-level data allowed selection of individual participants relevant to the review, with generally low risks of bias for the participant selection, reference standard and flow and timing domains. Most studies did not use a pre-specified threshold, which was considered a significant source of bias, however this did not affect quantitative analysis as we adopted a common rCBV threshold of 1.75 for the review. Concerns regarding applicability were low.From published and unpublished data, 115 participants were selected and included in the meta-analysis. Average rCBV (range) of 83 LGGs and 32 HGGs were 1.29 (0.01 to 5.10) and 1.89 (0.30 to 6.51), respectively. Using the widely accepted rCBV threshold of <1.75 to differentiate LGG from HGG, the summary sensitivity/specificity estimates were 0.83 (95% CI 0.66 to 0.93)/0.48 (95% CI 0.09 to 0.90). Sensitivity analysis using five good quality studies yielded sensitivity/specificity of 0.80 (95% CI 0.61 to 0.91)/0.67 (95% CI 0.07 to 0.98). Subgroup analysis for tumour histology showed sensitivity/specificity of 0.92 (95% CI 0.55 to 0.99)/0.42 (95% CI 0.02 to 0.95) in astrocytomas (6 studies, 55 participants) and 0.77 (95% CI 0.46 to 0.93)/0.53 (95% CI 0.14 to 0.88) in oligodendrogliomas+oligoastrocytomas (6 studies, 56 participants). Data were too sparse to investigate any differences across subgroups.

AUTHORS' CONCLUSIONS

The limited available evidence precludes reliable estimation of the performance of DSC MR perfusion-derived rCBV for the identification of grade in untreated solid and non-enhancing LGG from that of HGG. Pooled data yielded a wide range of estimates for both sensitivity (range 66% to 93% for detection of LGGs) and specificity (range 9% to 90% for detection of HGGs). Other clinical and methodological features affecting accuracy of the technique could not be determined from the limited data. A larger sample size of both LGG and HGG, preferably using a standardised scanning approach and with an updated reference standard incorporating molecular profiles, is required for a definite conclusion.

Current therapeutic approaches to diffuse grade II and III gliomas

The 2016 WHO classification of Tumors of the Central Nervous System brought major conceptual and practical changes in the classification of diffuse gliomas, by combining molecular features and histology into 'integrated' diagnoses. In diffuse gliomas, molecular profiling has thus become essential for nosological purposes, as well as to plan adequate treatment strategies and identify patients susceptible of target therapy. WHO grade II (low grade) and grade III (anaplastic) diffuse gliomas form a heterogeneous group of neoplasms, also known as 'lower-grade gliomas', characterized by a wide range of malignant potential. Molecular profile accounts for this biological diversity, and provides an accurate prognostic stratification of tumors in this group. Treatment strategies in lower-grade gliomas are ultimately based on molecular profile and WHO grade, as well as on patient characteristics such as age and Karnofsky performance status. The purpose of this review is to summarize recent advances in the classification of grade II and III gliomas, synthesize current treatment schemes according to molecular profile and describe ongoing research and future perspectives for the use of target therapies.

Relationship between the extent of resection and the survival of patients with low-grade gliomas: a systematic review and meta-analysis

BACKGROUND

Surgical resection is necessary to conduct a pathological biopsy and to achieve a reduction of intracranial pressure in low-grade gliomas patients. This study aimed to determine whether a greater extent of resection would increase the overall 5-year and 10-year survival of patients with low-grade gliomas.

METHODS

The studies addressing relationship between the extent of resection and the prognosis of low-grade gliomas updated until March 2017 were systematically searched in two databases (Pubmed and EMBASE). The relationships among categorical variables were analyzed using an odds ratio (OR) and a95% confidence interval (CI). Significance was established using CIs at a level of 95% or P < 0.05. Funnel plot was used to detect the publication bias.

RESULTS

Twenty articles (a total of 2128 patients) were identified. The meta-analysis showed that the 5-year (Odds ratio (OR), 3.90;95% Confidence Interval (CI), 2.79~5.45; P < 0.01; Z = 7.95) and 10-year OS (OR, 7.91; 95%CI, 5.12~12.22; P < 0.01; Z = 9.33) associated with gross total resection (GTR) were higher than those associated with subtotal resection (STR). Similarly, as compared with biopsy(BX), the 5-year and 10-year OS were higher after either GTR (5-year: OR, 5.43; 95%CI, 3.57~8.26; P < 0.01; Z = Z = 7.9; 10-year: OR, 10.17; 95%CI, 4.02~25.71; P < 0.00001; Z = 4.9) or STR (5-year: OR, 2.59; 95%CI, 1.81~ - 3.71; P < 0.00001; Z = 5.19; 10-year: OR, 2.21; 95%CI, 1.164.25; P = 0.02; Z = 2.39).

CONCLUSIONS

Our research found that a greater extent of resection could significantly increase the OS of patients with low-grade gliomas.

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.

Identifying clinical risk in low grade gliomas and appropriate treatment strategies, with special emphasis on the role of surgery

INTRODUCTION

Diffuse low-grade glioma (DLGG) is a chronic tumoral disease that ineluctably grows, migrates along white matter pathways, and progresses to a higher grade of malignancy. Areas covered: To determine the best individualized treatment attitude for each DLGG patient, and to redefine it over the years, i.e. to optimize the 'onco-functional balance' of serial and multimodal therapies, the understanding of the natural history of this chronic disease is crucial but not sufficient. A paradigmatic shift is to tailor the individual management according to the dynamic relationships between DLGG course and neural remodeling. In this spirit, a better knowledge of brain plasticity in a connectomal account of cerebral processing has enabled a dramatic improvement of both oncological and functional outcomes in DLGG patients, by increasing overall survival while preserving (or even improving) the quality of life. Expert commentary: Here, we propose an individualized and recursive therapeutic strategy in DLGG, leading to the concept of a 'personalized functional neuro-oncology', by emphasizing the role of early and maximal safe surgical resection(s) reliably achieved using intraoperative mapping of cortico-subcortical networks in awake patients.