Prognosis of glioblastoma patients improves significantly over time interrogating historical controls

BACKGROUND

Glioblastoma (GBM) is the most common devastating primary brain cancer in adults. In our clinical practice, median overall survival (mOS) of GBM patients seems increasing over time.

METHODS

To address this observation, we have retrospectively analyzed the prognosis of 722 newly diagnosed GBM patients, aged below 70, in good clinical conditions (i.e. Karnofsky Performance Status -KPS- above 70%) and treated in our department according to the standard of care (SOC) between 2005 and 2018. Patients were divided into two groups according to the year of diagnosis (group 1: from 2005 to 2012; group 2: from 2013 to 2018).

RESULTS

Characteristics of patients and tumors of both groups were very similar regarding confounding factors (age, KPS, MGMT promoter methylation status and treatments). Follow-up time was fixed at 24 months to ensure comparable survival times between both groups. Group 1 patients had a mOS of 19 months ([17.3-21.3]) while mOS of group 2 patients was not reached. The recent period of diagnosis was significantly associated with a longer mOS in univariate analysis (HR=0.64, 95% CI [0.51 - 0.81]), p < 0.001). Multivariate Cox analysis showed that the period of diagnosis remained significantly prognostic after adjustment on confounding factors (adjusted Hazard Ratio (aHR) 0.49, 95% CI [0.36-0.67], p < 0.001).

CONCLUSION

This increase of mOS over time in newly diagnosed GBM patients could be explained by better management of potentially associated non-neurological diseases, optimization of validated SOC, better management of treatments side effects, supportive care and participation in clinical trials.

OS07.1.A A threshold of mitotic activity and post-surgery residual volume are independant prognostic factors in astrocytoma IDH-mutant

Background

The distinction between grade 2 and 3 is instrumental to choose between observational follow-up and adjuvant treatment in resected astrocytoma IDH-mutant. However, criteria of grade 2 versus 3 have not been updated since the WHO 2007 classification. There is no consensus on the method of evaluation of the mitotic activity or a cut-off of mitoses separating grade 2 and grade 3 tumors. The objectives were to evaluate the maximal mitotic activity on a series of resected astrocytoma IDH-mutant and assess its prognostic impact on survival.

Material and Methods

Maximal mitotic activity on consecutive high power fields corresponding to 3 mm2 was examined in 118 lower-grade astrocytoma IDH-mutant. The prognostic value for time-to-treatment (TTT) and overall survival (OS) of mitotic activity and other putative prognostic factors (including age, performance status, pre-surgical tumor volume, plurilobar involvement, post-surgical residual tumor volume, midline involvement) was assessed in tumors with (i) ATRX loss, and (ii) without CDKN2A homozygous deletion, lesional enhancement, histological necrosis nor microvascular proliferation.

Results

Among the 75 (64%) of tumors which had gone through observational follow-up after resection, the maximal mitotic activity, the post-surgical residual volume and the plurilobar involvement were independent prognostic factors of TTT (p &lt; 0.0001). A threshold of mitotic activity for grade 2 was fitted on TTT and OS prognosis. Using this threshold, patients with “grade 2 tumors” had a median TTT of 55 months versus 19 months for “grade 3” (p = 0.0057) and a median OS of 102 months versus 73 months respectively (p = 0.001). Residual volume &lt; 1 cm3 was associated with longer OS (113 months versus 88 months, p = 0.0021).

Conclusion

Mitotic activity and post-surgical residual volume can be combined to evaluate prognosis in resected astrocytoma IDH-mutant and could select the best candidates for observational follow-up.

P14.16 Complete sustaining radiological response of a multi-recurrent disseminated adult medulloblastoma after antiangiogenic metronomic combined pediatric regimen MEMMAT: a case report

BACKGROUND

Even if medulloblastoma is considered as a curable disease, recurrent medulloblastoma has a poor prognosis, independently of therapy used. Medulloblastoma is very rare in adults, unlike children, and therapeutic strategies at recurrence are lacking. Nevertheless, adult teams sometimes use as “compassionate” chemotherapy some regimens published in children, such as the MEMMAT metronomic combination. However, this treatment, targeting both endothelial and proliferating tumor cells, has to date not been studied in the adult population.

MATERIAL AND METHODS

We present the case of a 40-year-old man, suffering from a right cerebellar SHH mutated medulloblastoma initially diagnosed and treated in 2014 by craniospinal radiotherapy associated with 4 cycles of carboplatine-VP16 following complete resection. Since April 2016, date of first relapse, numerous successive recurrences occurred, initially focal, treated by several surgeries (April and November 2016, January 2017), chemotherapy (rechallenge by carboplatine-VP16) then stereotactic radiotherapy. He then developed in October 2017 a new relapse in the posterior fossa, also associated with a meningeal dissemination on lumbar MRI. IK was 90%. He was then treated by TOTEM regimen (Temozolomide-Topotecan) followed by “Packer” regimen (Cisplatin-Belustine-Vincristin), without tumor control. However, because patient was non symptomatic with a KPS of 80%, we decided, according to the AJA French group, to propose what we presumed to be a “compassionate” chemotherapy, by metronomic pediatric regimen “MEMMAT”. For “supportive care” reasons, we decided not to realize the “Intrathecal part” of this regimen and administered to the patient intravenous bevacizumab (10 mg/kg d1-d14-d21), thalidomide (100 mg/d), celecoxib (300 mg bid), fenofibrate (160 mg/d) and etoposide (100 mg/d d1-21), alternating with cyclophosphamide (100 mg/d d22-42).

RESULTS

Clinical tolerance was very good, except grade 1 heel pain and fatigue; hematological toxicity was mild (transient grade 3 neutropenia, grade 4 lymphopenia); renal impairment, already present at the beginning, was increasing, and justified dose adjustment after 5 cycles and nephrologic explorations, ongoing. Radiological evaluation showed a complete radiological response with complete disappearance of enhancing lesions on first MRIs realized after 3 months (2 cycles); this response was confirmed after 6 months (4 cycles) and 9 months (6 cycles) on both cerebral and spinal MRI. Patient is now receiving the 7th cycle.

CONCLUSION

We report here the first case of a complete and sustaining response of an adult multi-recurrent metastatic medulloblastoma treated by a pediatric antiangiogenic metronomic regimen “MEMMAT”. This promising result incites to develop a dedicated prospective trial in adults in view to confirm the interest of this strategy.

PL1.2 Multiparametric assessment of factors influencing 2 HG accumulation in diffuse brain gliomas

BACKGROUND

2-hydroxyglutarate (2HG) can be detected non-invasively in IDH-mutant gliomas by in vivo magnetic resonance spectroscopy (MRS). We investigated factors affecting 2 HG accumulation and explored the prognostic value of 2 HG detection in IDH mutant gliomas and 2 HG variations during anti-cancer therapies.

MATERIAL AND METHODS

We prospectively scanned by MEGA-PRESS 70 glioma patients (24 before surgery and 46 IDH mutant operated glioma) and measured 2HG. CRLB cut-off was 50%. We followed up 9 IDH mutant patients during radiotherapy and chemotherapy.We analyzed radiological parameters (tumor and cystic/necrotic volumes, fractions of VOI filled with tumor, spectroscopic profile, “infiltrative” versus “expansive” morphology, contrast-enhancement) and genetic profile (IDH1, IDH2, 1p19q codeletion). 2HG concentrations in plasma, urine, and surgical obtained samples were measured by gas chromatography-mass spectrometry (GC-MS).

RESULTS

MEGA-PRESS sequence detected 2HG with a sensitivity of 95% in untreated patients, and of 69% in pre-treated patient. Positive predictive value was 100% in both groups. 2HG was lower in pre-treated IDH mutant gliomas (1.1 versus 2.3 mM, P=0.02) and decreased rapidly during radiotherapy and chemotherapy before any radiological change. 2HG detection was positively correlated with tumor volume (P=0.02), choline measurements (r=0.58 P<0.0001), cellular density (measured by restricted diffusivity, Pearson r -0.40 P=0.01), “expansive” presentation, mutated reads/total reads ratio by NGS and was inversely correlated with Myo-inositol (Pearson R -0.29 P=0.03) and cystic/necrotic areas (P=0.04). 2HG by MRS positively correlated with urine 2HG (r=0.80 P=0.003). 2 HG was higher in IDH2 mutant (4.7 versus 2.4 Mm, P=0.02) and lower in non R132H IDH1 mutant (1.12 mM P=0.004). Among IDH mutant glioma patients, 2 HG detection was associated with longer survival (HR 0.09; 95%CI 0.018–0.52).

CONCLUSION

Tumor volume, cellular density, previous radio- and chemotherapy and genetic features determine 2 HG detection in IDH mutant gliomas. 2 HG detection is associated with better outcome and can be reliably monitored during anti-cancer treatments.

In Vivo Measurement of Brain Tumor Elasticity Using Intraoperative Shear Wave Elastography

Purpose: Objective Shear wave elastography (SWE) enabled living tissue assessment of stiffness. This is routinely used for breast, thyroid and liver diseases, but there is currently no data for the brain. We aim to characterize elasticity of normal brain parenchyma and brain tumors using SWE. Materials and Methods: Patients with scheduled brain tumor removal were included in this study. In addition to standard ultrasonography, intraoperative SWE using an ultrafast ultrasonic device was used to measure the elasticity of each tumor and its surrounding normal brain. Data were collected by an investigator blinded to the diagnosis. Descriptive statistics, box plot analysis as well as intraoperator and interoperator reproducibility analysis were also performed. Results: 63 patients were included and classified into four main types of tumor: meningiomas, low-grade gliomas, high-grade gliomas and metastasis. Young's Modulus measured by SWE has given new insight to differentiate brain tumors: 33.1 ± 5.9 kPa, 23.7 ± 4.9 kPa, 11.4 ± 3.6 kPa and 16.7 ± 2.5 kPa, respectively, for the four subgroups. Normal brain tissue has been characterized by a reproducible mean stiffness of 7.3 ± 2.1 kPa. Moreover, low-grade glioma stiffness is different from high-grade glioma stiffness (p = 0.01) and normal brain stiffness is very different from low-grade gliomas stiffness (p < 0.01). Conclusion: This study demonstrates that there are significant differences in elasticity among the most common types of brain tumors. With intraoperative SWE, neurosurgeons may have innovative information to predict diagnosis and guide their resection.

A case of bilateral frontal tumors without "frontal syndrome"

We report the longitudinal case study of a right-handed patient harboring two frontal tumors that benefited from bilateral simultaneous surgery. The tumors were WHO Grade II gliomas located in the left inferior frontal area (including the cingulate gyrus) and the right anterior superior frontal gyrus. The double tumor resection was guided by direct electrical stimulation of brain areas while the patient was awake. Neuropsychological assessments were administered before and after the surgery to analyse how the brain functions in the presence of two frontal gliomas that affect both hemispheres and reacts to a bilateral resection, which can brutally compromise the neuronal connectivity, progressively established during the infiltrating process. We showed that both the tumor infiltration and their bilateral resection did not lead to a "frontal syndrome" or a "dysexecutive syndrome" predicted by the localization models. However, a subtle fragility was observed in fine-grain language, memory and emotional skills. This case study reveals the significance of brain plasticity in the reorganization of cognitive networks, even in cases of bilateral tumors. It also confirms the clinical relevance of hodotopical brain models, which considers the brain to be organized in parallel-distributed networks around cortical centers and epicenters.

Improving the time-machine: estimating date of birth of grade II gliomas

OBJECTIVES

Here we present a model aiming to provide an estimate of time from tumour genesis, for grade II gliomas. The model is based on a differential equation describing the diffusion-proliferation process. We have applied our model to situations where tumour diameter was shown to increase linearly with time, with characteristic diametric velocity.

MATERIALS AND METHODS

We have performed numerical simulations to analyse data, on patients with grade II gliomas and to extract information concerning time of tumour biological onset, as well as radiology and distribution of model parameters.

RESULTS AND CONCLUSIONS

We show that the estimate of tumour onset obtained from extrapolation using a constant velocity assumption, always underestimates biological tumour age, and that the correction one should add to this estimate is given roughly by 20/v (year), where v is the diametric velocity of expansion of the tumour (expressed in mm/year). Within the assumptions of the model, we have identified two types of tumour: the first corresponds to very slowly growing tumours that appear during adolescence, and the second type corresponds to slowly growing tumours that appear later, during early adulthood. That all these tumours become detectable around a mean patient age of 30 years could be interesting for formulation of strategies for early detection of tumours.

Predicting the outcome of grade II glioma treated with temozolomide using proton magnetic resonance spectroscopy

Background:

This study was designed to evaluate proton magnetic resonance spectroscopy (¹H-MRS) for monitoring the WHO grade II glioma (low-grade glioma (LGG)) treated with temozolomide (TMZ).

Methods:

This prospective study included adult patients with progressive LGG that was confirmed by magnetic resonance imaging (MRI). Temozolomide was administered at every 28 days. Response to TMZ was evaluated by monthly MRI examinations that included MRI with volumetric calculations and ¹H-MRS for assessing Cho/Cr and Cho/NAA ratios. Univariate, multivariate and receiver-operating characteristic statistical analyses were performed on the results.

Results:

A total of 21 LGGs from 31 patients were included in the study, and followed for at least n=14 months during treatment. A total of 18 (86%) patients experienced a decrease in tumour volume with a greater decrease of metabolic ratios. Subsequently, five (28%) of these tumours resumed growth despite the continuation of TMZ administration with an earlier increase of metabolic ratios of 2 months. Three (14%) patients did not show any volume or metabolic change. The evolutions of the metabolic ratios, mean(Cho/Cr)_n and mean(Cho/NAA)_n, were significantly correlated over time (Spearman ρ=+0.95) and followed a logarithmic regression (P>0.001). The evolutions over time of metabolic ratios, mean(Cho/Cr)_n and mean(Cho/NAA)_n, were significantly correlated with the evolution of the mean relative decrease of tumour volume, mean(ΔV_n/V_o), according to a linear regression (P<0.001) in the ‘response/no relapse’ patient group, and with the evolution of the mean tumour volume (meanV_n), according to an exponential regression (P<0.001) in the ‘response/relapse’ patient group. The mean relative decrease of metabolic ratio, mean(Δ(Cho/Cr)_n/(Cho/Cr)_o), at n=3 months was predictive of tumour response over the 14 months of follow-up. The mean relative change between metabolic ratios, mean((Cho/NAA)_n−(Cho/Cr)_n)/(Cho/NAA)_n, at n=4 months was predictive of tumour relapse with a significant cutoff of 0.046, a sensitivity of 60% and a specificity of 100% (P=0.004).

Conclusions:

The ¹H-MRS profile changes more widely and rapidly than tumour volume during the response and relapse phases, and represents an early predictive factor of outcome over 14 months of follow-up. Thus, ¹H-MRS may be a promising, non-invasive tool for predicting and monitoring the clinical response to TMZ.

Retrospective review of prognostic factors, including 1p19q deletion, in low-grade oligodendrogliomas and a review of recent published works

The purpose of the present study was to investigate potential prognostic factors in low-grade oligodendrogliomas (LGOs), particularly 1p19q deletion, due to its proven prognostic significance in anaplastic oligodendrogliomas. We carried out a retrospective review of patients with a histological diagnosis of LGO between 1990 and 2000 in Auckland and Wellington, New Zealand. All cases underwent central histopathological review and FISH testing for 1p19q status. Univariate analysis of potential prognostic factors including 1p19q status, age, tumour size, tumour crossing midline, tumour enhancement, extent of surgery and seizures at diagnosis was carried out. Thirty-one patients were eligible and FISH testing was successful in 28 specimens (90%). Twenty-three specimens (82%) had 1p19q deletion; four (14%) had no 1p19q deletion; and one (4%) had 1p deletion alone. At a median follow-up of 87 months (0-147 months), median survival had not been reached and no significant difference in overall survival (OS) based on 1p19q status was detected (1p19q deletion OS 56%; 1p19q intact OS 0%; 1p deletion alone 100% (P = 0.38)). None of the other prognostic factors investigated reached statistical significance. We confirmed the high incidence (82%) of combined 1p19q deletion in LGOs and the feasibility of successful FISH testing in paraffin embedded specimens up to 10-years-old. Analysis of potential prognostic factors was limited by the lack of events during the follow-up period.

Esthesioneuroblastoma: a case report of diffuse subdural recurrence and review of recently published studies

Esthesioneuroblastoma is a rare malignancy arising from the olfactory epithelium. We present a case history of a 75-year-old man who presented with a Kadish stage C esthesioneuroblastoma and underwent craniofacial surgery and adjuvant radiotherapy. Two years later he was found to have diffuse subdural deposits with distant bone and nodal metastases, treated with further radiotherapy. The patient's condition subsequently deteriorated and he died. Given this unusual pattern of failure, we review the recent published studies regarding the natural history, treatment and outcome for this tumour.

Temozolomide for low-grade gliomas: predictive impact of 1p/19q loss on response and outcome

OBJECTIVE

To evaluate the predictive impact of chromosome 1p/19q deletions on the response and outcome of progressive low-grade gliomas (LGG) treated with up-front temozolomide (TMZ) chemotherapy.

METHODS

Adult patients with measurable, progressive LGG (WHO grade II) treated with TMZ delivered at the conventional schedule (200 mg/m(2)/day for 5 consecutive days, repeated every 28 days) were retrospectively evaluated for response by central review of MRI-s. Chromosome 1p and 19q deletions were detected by the loss of the heterozygosity technique (LOH).

RESULTS

A total of 149 consecutive patients were included in this retrospective, single center observational study. The median number of TMZ cycles delivered was 14 (range 2 to 30). Seventy-seven patients (53%) experienced an objective response (including 22 [15%] cases of partial response and 55 [38%] cases of minor response), 55 (37%) patients had stable disease, and 14 (10%) had a progressive disease. The median time to maximum tumor response was 12 months (range 3 to 30 months). The median progression-free survival (PFS) was 28 months (95% CI: 23.4 to 32.6). Material for genotyping was available for 86 patients. Combined 1p/19q LOH was present in 42% of the cases and was significantly associated with a higher rate (p = 0.02) and longer objective response to chemotherapy (p = 0.017), and both longer PFS (p = 4.10(-5)) and overall survival (p = 0.04).

CONCLUSION

Low-grade gliomas respond to temozolomide and loss of chromosome 1p/19q predicts both a durable chemosensitivity and a favorable outcome.

IRM fonctionnelle cérébrale : bases physiologiques, techniques et applications cliniques

Brain functional MRI (fMRI) provides an indirect mapping of cerebral activity, based on the detection of local changes in blood flow and oxygenation levels that are associated with neuronal activity (BOLD contrast). fMRI allows noninvasive studies of normal and pathological aspects of the brain's functional organization. It is based on the comparison of two or more cognitive states. Echoplanar imaging is the technique of choice, providing the quickest study of the entire brain. Activation maps are calculated from a statistical analysis of the local signal changes. fMRI has become one of the most widely used functional imaging techniques in neuroscience. In clinical practice, fMRI can identify eloquent areas involved in motor and language functions in surgical patients and can evaluate the risk of postoperative neurological deficit.

Fatal hemorrhagic complication following endovascular treatment of a cerebral arteriovenous malformation

Evaluation of the natural history of brain Arteriovenous Malformations (AVMs) including its morbidity and mortality is a crucial point in the management of patients having a cerebral AVM. The risks associated with the AVM natural history, especially regarding the occurrence of an hemorrhage, have to be compared to the risks due to the therapeutic approach. In the literature, the risk of annual bleeding of an AVM is estimated from 2 to 4%. Morbidity from AVM rupture is estimated from 13% to 50% with a risk of mortality reported from 3 to 30%. Endovascular treatment is an efficient tool in the therapy of these lesions. However, AVM embolization remains a difficult procedure. Complications of the endovascular treatment must be evaluated in relation to the potential risk associated to the AVM natural history. After AVM endovascular treatment, morbidity with permanent neurological deficit is reported in 0.4% to 12.5% of patients and mortality in 0.4% to 7.5%. In more recent reports, after brain AVM embolization, a permanent neurological deficit is estimated to occur in 9% of patients and death in 2%. Hemorrhage appears the most frequent and serious complication in the endovascular treatment of a brain AVM. We report a case of fatal hemorrhagic complication following endovascular treatment of a cerebral AVM in a 20 year old patient. This case contributes to remind that embolization, even in specialized centers with experience in the management of this pathology, can be followed by a poor and even fatal outcome. In most cases, the treatment is performed in order to protect the patient of a potential risk. Consequently, the complication of the embolization must always be carefully considered and discussed between the medical team, the patient and its family for planning the AVM endovascular treatment.

[French neurosurgical practice in Neuro-Oncology (national survey--part I)]

OBJECTIVE

The aim of this work is to summarize the elements of the "Cancer Plan" applicable to neurosurgical practice, and to give the results of a national inquiry concerning the daily practice of Neuro-Oncology from the neurosurgical point of view.

METHOD

The Neuro-Oncology Group of the French Society of Neurosurgery has submitted a questionnaire to every department of Neurosurgery in France.

RESULTS

The response rate of the public centers was 96.5%. Moreover, responses were available from 7 private centers. The results are detailed in the text.

CONCLUSION

This national survey highlights the interest and implication of French neurosurgeons in the field of Neuro-Oncology. But also, to be in accordance with the guidelines for good clinical practice, the importance of developing official neuro-oncological networks in order to offer the best access to clinical and fundamental data and hence optimise patient's care. The publication of the "Cancer Plan", the creation of a National Neuro-Oncology Group, and the results of this survey (actual multidisciplinary approach, better information and transparency, individualized care of the patients), are in the line with updating our daily practice, even though discrepancies remain among centers. French neurosurgeons must continue along the same path, but at the same time there is a need for additional help to definitely reach a truly, and homogeneous, optimized care of neuro-oncological patients.

The role of dominant striatum in language: a study using intraoperative electrical stimulations

BACKGROUND

The role of the striatum in language remains poorly understood. Intraoperative electrical stimulation during surgery for tumours involving the caudate nucleus or putamen in the dominant hemisphere might be illuminating.

OBJECTIVES

To study the role of these structures in language, with the aim of avoiding postoperative definitive aphasia.

METHODS

11 patients with cortico-subcortical low grade gliomas were operated on while awake, and striatal functional mapping was done. Intraoperative direct electrical stimulation was used while the patients carried out motor and naming tasks during the resection.

RESULTS

In five cases of glioma involving the dominant putamen, stimulations induced anarthria, while in six cases of glioma involving the dominant caudate, stimulations elicited perseveration. There was no motor effect. The striatum was systematically preserved. Postoperatively, all patients except one had transient dysphasia which resolved within three months.

CONCLUSIONS

There appear to be two separate basal ganglia systems in language, one mediated by the putamen which might have a motor role, and one by the caudate which might have a role in cognitive control. These findings could have implications for surgical strategy in lesions involving the dominant striatum.

Contribution of intraoperative electrical stimulations in surgery of low grade gliomas: a comparative study between two series without (1985-96) and with (1996-2003) functional mapping in the same institution

OBJECTIVES

Despite the growing use of intraoperative functional mapping in supratentorial low grade glioma (LGG) surgery, few studies have compared series of patients operated on without and with direct electrical stimulation (DES) by the same team. The present study compared the rate of LGG surgery performed in eloquent areas, the rate of postoperative sequelae, and the quality of resection during two consecutive periods in the same department-the first without and the second with the use of intraoperative electrophysiology.

METHODS

Between 1985 and 1996, 100 patients harbouring a supratentorial LGG underwent surgery with no functional mapping (S1). Between 1996 and 2003, 122 patients were operated on in the same department for a supratentorial LGG using intraoperative cortico-subcortical DES (S2).

RESULTS

Comparison between the two series showed that 35% of LGGs were operated on in eloquent areas in S1 versus 62% in S2 (p<0.0001), with 17% severe permanent deficits in S1 versus 6.5% in S2 (p<0.019). On postoperative MRI, 37% of resections were subtotal and 6% total in S1 versus 50.8% and 25.4%, respectively, in S2 (p<0.001). In both groups, survival was significantly related to the quality of resection.

CONCLUSIONS

The results of the present study allow, for the first time, quantification of the contribution of intraoperative DES in LGG resection. Indeed, the use of this method leads to the extension of indications of LGG surgery within eloquent areas; to a decrease in the risk of sequelae; and to improvement of the quality of tumour resection, with an impact on survival.

Neurochirurgie et neuro-oncologie : état des lieux (II)

OBJECTIVE

This second part of the inquiry of the NeuroOncolgy Group of the French Neurosurgical Society was undertaken to evaluate the involvement of French neurosurgeons in brain tumor research.

METHODS

In December 2003, A questionnaire called "Census of current and future research studies about brain tumors in your center" has been mailed to every French neurosurgical department. For each protocol, responders were asked to mention: the title of the protocol, its mono- or multi-centric design, the name of the principal investigator, the name of the neurosurgeon(s) involved in the study, the topic of the study (epidemiology, imaging, biology, genetics, therapy), tumor histology, financial support, and partners.

RESULTS

Twenty-three centers responded. Sixty-three studies were described. There were 6 epidemiological studies, 7 imaging studies, 27 biological or genetic studies and 15 clinical trials concerning glial tumors, and 8 biological studies concerning non glial tumors. Each study is described in the text with the data previously mentioned.

CONCLUSION

Despite the fact that several centers did not answer, this inquiry confirmed the strong involvement of French neurosurgeons in brain tumor research.

Effet de la grandeur décimale sur la lecture de chiffres dans les gliomes du carrefour gauche

An increasing number of studies are focusing on the anatomo-functional organisation of number processing and some cognitive models have been recently developed. Nevertheless, relationships between areas implicated in number processing, and language areas and circuits remain unclear. Recently, Dehaene and Cohen, in their "triple-code model of number processing", (Dehaene and Cohen, 1995) distinguished two alternative number representation and processing systems: one depending on verbal processes, the other representing a quantity manipulation. According to this model, the retrieval of "arithmetical facts" (AF), learned by rote at school and memorised in a verbal form (such as the multiplication table or simple addition problems) can be considered as a verbal automatism; conversely, subtraction problems, which require mental manipulation of the quantities, represent an abstract, semantic elaboration: "Actual Calculation" (AC). The anatomical correlate of the retrieval of AF (depending on automatic verbal associations) seems to correspond to the left-hemispheric perisylvian areas, while impairment of the actual calculation (AC) depends on the intraparietal region, particularly in the left dominant hemisphere. The present study describes the neuropsychological assessment of three patients, tested after surgery for left parieto-occipital tumors. Two of them were affected by an anaplasic glioma, the third by a low-grade glioma. The cognitive evaluation included: words of Rey, numeral (directed and reversed) span, reading of "simple" numbers (from 1 to 10) and of "complex" numbers (many decimals), writing (dictation) and reading a standard text, finger denomination and right-left distinction. All patients showed language disturbances, dysgraphia and severe dyslexia. In reading numbers, we identified two types of errors: lexical and syntactic. "Lexical errors" consisted in a wrong choice among words in the number's lexicon. For instance, all patients made errors in reading "complex" numbers composed by many decimals, switching single numbers but respecting the decimal size and the structure of the whole number (such as 69107 instead of 68107). On the other hand, only one patient committed syntactic errors, misunderstanding the decimal size and the structure of the number. We considered lexical errors as verbal errors, and syntactic errors as semantic errors, affecting the notion of quantity. We tried to explain verbal disturbances as well as lexical errors as a consequence of lesion of the left-hemispheric perisylvian areas, while syntactic errors as a consequence of impairment of the intraparietal region.

Correlations between molecular profile and radiologic pattern in oligodendroglial tumors

Objective: To investigate possible correlations between tumor location and genetic alterations in a series of oligodendrogliomas.

Methods: A series of 158 consecutive oligodendrogliomas were retrospectively reviewed. In each case, the radiologic picture and the chromosome 1p (chr 1p) status of the tumor detected by the loss of heterozygosity technique were analyzed. Correlation between tumor location and molecular profile was made by χ2 tests.

Results: Eighty-eight of the 158 patients had low-grade oligodendrogliomas, and 70 had anaplastic oligodendrogliomas. Overall, oligodendrogliomas with chr 1p loss were located preferentially in the anterior part of the brain, whereas tumors with intact chr 1p affected mainly the posterior part of the brain (p = 0.0038). In terms of lobar involvement, a preferential location of oligodendrogliomas with chr 1p loss was found in the frontal lobes as compared with the temporal, parietal, and occipital tumors (p < 0.01).

Conclusion: There is a significant correlation between loss of heterozygosity on chromosome 1p and tumor location in oligodendrogliomas, suggesting that subtypes of oligodendrogliomas could derive from site-specific precursors.

Temozolomide as initial treatment for adults with low-grade oligodendrogliomas or oligoastrocytomas and correlation with chromosome 1p deletions

PURPOSE

To determine the response rate of low-grade oligodendroglial tumors (LGOT) to temozolomide (TMZ) as initial treatment and to evaluate the predictive value of chromosome 1p deletion on the radiologic response.

PATIENTS AND METHODS

Adult patients with pathologically proven LGOT with progressive disease on magnetic resonance imaging (MRI) were eligible for the study. TMZ was administered at the starting dose of 200 mg/m2/d for 5 days, repeated every 28 days. Response was evaluated clinically and by central review of MRIs. Chromosome 1p and 19q deletions were detected by the loss of heterozygosity technique.

RESULTS

Sixty consecutive patients were included in the study. At the time of analysis, the median number of TMZ cycles delivered was 11. Clinically, 51% of patients improved, particularly those with uncontrolled epilepsy. The objective radiologic response rate was 31% (17% partial response and 14% minor response), whereas 61% of patients had stable disease and 8% experienced disease progression. The median time to maximum tumor response was 12 months (range, 5 to 20 months). Myelosuppression was the most frequent side effect, with grade 3 to 4 toxicity in 8% of patients. Loss of chromosome 1p was associated with objective tumor response (P < .004).

CONCLUSION

TMZ is well tolerated and provides a substantial rate of response in LGOT. Chromosome 1p loss is correlated with radiographic response and could be a helpful marker for guiding therapeutic decision making in LGOT.

Role of the healthy hemisphere in recovery after resection of the supplementary motor area

Objective: To determine the compensatory mechanisms involved in the recovery of motor function following surgical lesions of the supplementary motor area (SMA) and their relation to the clinical characteristics of recovery.

Subjects and Methods: Twelve patients were referred for surgery of low-grade gliomas located in the SMA, and compared to eight healthy controls using fMRI before and after surgery during self-paced movements of both hands, successively. Magnitude and volume of activation within regions of interest (primary sensorimotor cortex, premotor cortex, SMA, preSMA, and parietal lobes) were compared and tested for correlation with anatomic characteristics of the tumor and resection, and clinical data.

Results: Tumor growth induced preoperative underactivity in the adjacent SMA and overactivity in the opposite SMA. Postoperative recovery was associated with recruitment of a premotor network located in the healthy hemisphere including the SMA and the lateral premotor cortex. Postoperative premotor recruitment in the healthy hemisphere increased with the percentage of resection of preoperative SMA activation. Shortened onset and duration of recovery was associated with increased preoperative changes in activation levels.

Conclusions: These findings suggest a dysfunction of the SMA ipsilateral to the tumor, partially compensated by a recruitment of the contralesional SMA which correlated with shortened postoperative recovery. SMA resection was compensated by the recruitment of a medial and lateral premotor circuitry in the healthy hemisphere.

Intra-operative mapping of the subcortical visual pathways using direct electrical stimulations

Despite the risk of postoperative visual field defect following surgery within the temporo-parieto-occipital region, visual mapping has rarely been described, in particular at the subcortical level. In this report, we successfully performed a subcortical mapping of the visual pathways using intra-operative electrical stimulations (IES), during surgery under local anesthesia for a low-grade glioma invading the whole temporal lobe and the temporo-occipital junction. The optic radiations then constituted the posterior and deep functional boundary of the resection, avoiding the occurrence of a post-operative hemianopsia, in spite of an asymptomatic quadrantanopsia. This preliminary experience illustrates the possibility to use intra-operative direct electrical stimulation during surgery of lesions involving the posterior afferent visual system, in order to identify and then preserve the visual pathways, as previously reported for sensorimotor and language subcortical fibers.

Functional recovery after surgical resection of low grade gliomas in eloquent brain: hypothesis of brain compensation

OBJECTIVES

To describe functional recovery after surgical resection of low grade gliomas (LGG) in eloquent brain areas, and discuss the mechanisms of compensation.

METHODS

Seventy-seven right-handed patients without deficit were operated on for a LGG invading primary and/or secondary sensorimotor and/or language areas, as shown anatomically by pre-operative MRI and intraoperatively by electrical brain stimulation and cortico-subcortical mapping.

RESULTS

Tumours involved 31 supplementary motor areas, 28 insulas, 8 primary somatosensory areas, 4 primary motor areas, 4 Broca's areas, and 2 left temporal language areas. All patients had immediate post-operative deficits. Recovery occurred within 3 months in all except four cases (definitive morbidity: 5%). Ninety-two percent of the lesions were either totally or extensively resected on post-operative MRI.

CONCLUSIONS

These findings suggest that spatio-temporal functional re-organisation is possible in peritumoural brain, and that the process is dynamic. The recruitment of compensatory areas with long term perilesional functional reshaping would explain why: before surgery, there is no clinical deficit despite the tumour growth in eloquent regions; immediately after surgery, the occurrence of a deficit, which could be due to the resection of invaded areas participating (but not essential) to the function; and why three months after surgery, almost complete recovery had occurred. This brain plasticity, which decreases the long term risk of surgical morbidity, may be used to extend the limits of surgery in eloquent areas.