Clinical prognostic factors in patients with malignant glioma treated with combined modality approach

The FDA NIH Biomarkers, EndpointS, and other Tools (BEST) resource in neuro-oncology

In early 2016, the FDA and the National Institutes of Health (NIH) published the first version of the glossary included in the Biomarkers, EndpointS, and other Tools (BEST) resource.1 The BEST glossary was constructed to harmonize and clarify terms used in translational science and medical product development and to provide a common language used for communication by those agencies. It is considered a "living" document that will be updated in the future. This review will discuss the main biomarker and clinical outcome categories contained in the BEST glossary as they apply to neuro-oncology, as well as the overlapping and hierarchical relationships among them.

Machine Learning Versus Logistic Regression Methods for 2-Year Mortality Prognostication in a Small, Heterogeneous Glioma Database

Background

Machine learning (ML) is the application of specialized algorithms to datasets for trend delineation, categorization, or prediction. ML techniques have been traditionally applied to large, highly dimensional databases. Gliomas are a heterogeneous group of primary brain tumors, traditionally graded using histopathologic features. Recently, the World Health Organization proposed a novel grading system for gliomas incorporating molecular characteristics. We aimed to study whether ML could achieve accurate prognostication of 2-year mortality in a small, highly dimensional database of patients with glioma.

Methods

We applied 3 ML techniques (artificial neural networks [ANNs], decision trees [DTs], and support vector machines [SVMs]) and classical logistic regression (LR) to a dataset consisting of 76 patients with glioma of all grades. We compared the effect of applying the algorithms to the raw database versus a database where only statistically significant features were included into the algorithmic inputs (feature selection).

Results

Raw input consisted of 21 variables and achieved performance of accuracy/area (C.I.) under the curve of 70.7%/0.70 (49.9-88.5) for ANN, 68%/0.72 (53.4-90.4) for SVM, 66.7%/0.64 (43.6-85.0) for LR, and 65%/0.70 (51.6-89.5) for DT. Feature selected input consisted of 14 variables and achieved performance of 73.4%/0.75 (62.9-87.9) for ANN, 73.3%/0.74 (62.1-87.4) for SVM, 69.3%/0.73 (60.0-85.8) for LR, and 65.2%/0.63 (49.1-76.9) for DT.

Conclusions

We demonstrate that these techniques can also be applied to small, highly dimensional datasets. Our ML techniques achieved reasonable performance compared with similar studies in the literature. Although local databases may be small versus larger cancer repositories, we demonstrate that ML techniques can still be applied to their analysis; however, traditional statistical methods are of similar benefit.

Clinical Significance of Extracellular Vesicles in Plasma from Glioblastoma Patients

PURPOSE

Glioblastoma (GBM) is the most common primary brain tumor. The identification of blood biomarkers reflecting the tumor status represents a major unmet need for optimal clinical management of patients with GBM. Their high number in body fluids, their stability, and the presence of many tumor-associated proteins and RNAs make extracellular vesicles potentially optimal biomarkers. Here, we investigated the potential role of plasma extracellular vesicles from patients with GBM for diagnosis and follow-up after treatment and as a prognostic tool.

EXPERIMENTAL DESIGN

Plasma from healthy controls (n = 33), patients with GBM (n = 43), and patients with different central nervous system malignancies (n = 25) were collected. Extracellular vesicles were isolated by ultracentrifugation and characterized in terms of morphology by transmission electron microscopy, concentration, and size by nanoparticle tracking analysis, and protein composition by mass spectrometry. An orthotopic mouse model of human GBM confirmed human plasma extracellular vesicle quantifications. Associations between plasma extracellular vesicle concentration and clinicopathologic features of patients with GBM were analyzed. All statistical tests were two-sided.

RESULTS

GBM releases heterogeneous extracellular vesicles detectable in plasma. Plasma extracellular vesicle concentration was higher in GBM compared with healthy controls (P < 0.001), brain metastases (P < 0.001), and extra-axial brain tumors (P < 0.001). After surgery, a significant drop in plasma extracellular vesicle concentration was measured (P < 0.001). Plasma extracellular vesicle concentration was also increased in GBM-bearing mice (P < 0.001). Proteomic profiling revealed a GBM-distinctive signature.

CONCLUSIONS

Higher extracellular vesicle plasma levels may assist in GBM clinical diagnosis: their reduction after GBM resection, their rise at recurrence, and their protein cargo might provide indications about tumor, therapy response, and monitoring.

Choline-to-N-acetyl aspartate and lipids-lactate-to-creatine ratios together with age assemble a significant Cox's proportional-hazards regression model for prediction of survival in high-grade gliomas

OBJECTIVE

A long-lasting concern has prevailed for the identification of predictive biomarkers for high-grade gliomas (HGGs) using MRI. However, a consensus of which imaging parameters assemble a significant survival model is still missing in the literature; we investigated the significant positive or negative contribution of several MR biomarkers in this tumour prognosis.

METHODS

A retrospective cohort of supratentorial HGGs [11 glioblastoma multiforme (GBM) and 17 anaplastic astrocytomas] included 28 patients (9 females and 19 males, respectively, with a mean age of 50.4 years, standard deviation: 16.28 years; range: 13-85 years). Oedema and viable tumour measurements were acquired using regions of interest in T₁ weighted, T₂ weighted, fluid-attenuated inversion recovery, apparent diffusion coefficient (ADC) and MR spectroscopy (MRS). We calculated Kaplan-Meier curves and obtained Cox's proportional hazards.

RESULTS

During the follow-up period (3-98 months), 17 deaths were recorded. The median survival time was 1.73 years (range, 0.287-8.947 years). Only 3 out of 20 covariates (choline-to-N-acetyl aspartate and lipids-lactate-to-creatine ratios and age) showed significance in explaining the variability in the survival hazards model; score test: χ² (3) = 9.098, p = 0.028.

CONCLUSION

MRS metabolites overcome volumetric parameters of peritumoral oedema and viable tumour, as well as tumour region ADC measurements. Specific MRS ratios (Cho/Naa, L-L/Cr) might be considered in a regular follow-up for these tumours. Advances in knowledge: Cho/Naa ratio is the strongest survival predictor with a log-hazard function of 2.672 in GBM. Low levels of lipids-lactate/Cr ratio represent up to a 41.6% reduction in the risk of death in GBM.

Clinical outcome assessment in malignant glioma trials: measuring signs, symptoms, and functional limitations

The shared goal of all parties developing therapeutics against malignant gliomas is to positively impact the lives of people affected by these cancers. Clinical outcome assessment (COA) tools, including measures of patient-reported outcome, performance outcome, clinician-reported outcome, and observer-reported outcome, allow patient-focused assessments to complement traditional efficacy measures such as overall survival and radiographic endpoints. This review examines the properties of various COA measures used in malignant glioma clinical trials to date and cross references their content to the priority signs, symptoms, and functional limitations defined through a community survey conducted by the National Brain Tumor Society. The overarching goal of this initiative is to identify COA measures that are feasible and have appropriate psychometric properties for use in this patient population as well as highlight where further development is needed.

The Metabolic Epicenter of Supratentorial Gliomas: A 1H-MRSI Study

Background:

Assessing the impact of glioma location on prognosis remains elusive. We approached the problem using multivoxel proton magnetic resonance spectroscopic imaging (1H-MRSI) to define a tumor “metabolic epicenter”, and examined the relationship of metabolic epicenter location to survival and histopathological grade.

Methods:

We studied 54 consecutive patients with a supratentorial glioma (astrocytoma or oligodendroglioma, WHO grades II-IV). The metabolic epicenter in each tumor was defined as the 1H-MRSI voxel containing maximum intra-tumoral choline on preoperative imaging. Tumor location was considered the X-Y-Z coordinate position, in a standardized stereotactic space, of the metabolic epicenter. Correlation between epicenter location and survival or grade was assessed.

Results:

Metabolic epicenter location correlated significantly with patient survival for all tumors (r2 = 0.30, p = 0.0002) and astrocytomas alone (r2 = 0.32, p = 0.005). A predictive model based on both metabolic epicenter location and histopathological grade accounted for 70% of the variability in survival, substantially improving on histology alone to predict survival. Location also correlated significantly with grade (r2 = 0.25, p = 0.001): higher grade tumors had a metabolic epicenter closer to the midpoint of the brain.

Conclusions:

The concept of the metabolic epicenter eliminates several problems related to existing methods of classifying glioma location. The location of the metabolic epicenter is strongly correlated with overall survival and histopathological grade, suggesting that it reflects biological factors underlying glioma growth and malignant dedifferentiation. These findings may be clinically relevant to predicting patterns of local glioma recurrence, and in planning resective surgery or radiotherapy.

The Clinic of Neurosurgery at the Clinical Center of Serbia in Belgrade--building on the past

Neurosurgery as an independent discipline in Serbia has a distinguished history, beginning in 1938 when Dr. Milivoje Kostic, Professor and Chairman of Surgery, opened the Department of Neurosurgery within the Clinic of Surgery in Belgrade. Since then, thanks to the founding fathers' efforts and their successors' work, the Clinic for Neurosurgery in Belgrade has become a highly specialized health, scientific, and educational institution that is part of the University of Belgrade and is a referral center for all neurosurgical clinics in Serbia. Currently, the Clinic for Neurosurgery, with 160 patient beds, is one of the largest European institutions of its kind. Neurosurgery at the Clinical Center of Serbia (CCS) involves a wide range of patients and resources, with an average daily inpatient census of 15 to 20 patients. Each year, there are more than 3000 admissions at the neurosurgical service. Approximately 3500 operations per year are performed in the main campus neurosurgical operating rooms of CCS, while approximately 15,000 patients alone are evaluated in emergency room or inpatient consultations. Despite economic restraints, the department continues to grow in strength, and we remain optimistic of exciting times ahead for neurosurgery at the CCS.

Prospective cohort study of radiotherapy with concomitant and adjuvant temozolomide chemotherapy for glioblastoma patients with no or minimal residual enhancing tumor load after surgery

Survival of glioblastoma patients has been linked to the completeness of surgical resection. Available data, however, were generated with adjuvant radiotherapy. Data confirming that extensive cytoreduction remains beneficial to patients treated with the current standard, concomitant temozolomide radiochemotherapy, are limited. We therefore analyzed the efficacy of radiochemotherapy for patients with little or no residual tumor after surgery. In this prospective, non-interventional multicenter cohort study, entry criteria were histological diagnosis of glioblastoma, small enhancing or no residual tumor on post-operative MRI, and intended temozolomide radiochemotherapy. The primary study objective was progression-free survival; secondary study objectives were survival and toxicity. Furthermore, the prognostic value of O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation was investigated in a subgroup of patients. One-hundred and eighty patients were enrolled. Fourteen were excluded by patient request or failure to initiate radiochemotherapy. Twenty-three patients had non-evaluable post-operative imaging. Thus, 143 patients qualified for analysis, with 107 patients having residual tumor diameters ≤1.5 cm. Median follow-up was 24.0 months. Median survival or patients without residual enhancing tumor exceeded the follow-up period. Median survival was 16.9 months for 32 patients with residual tumor diameters >0 to ≤1.5 cm (95% CI: 13.3-20.5, p = 0.039), and 13.9 months (10.3-17.5, overall p < 0.001) for 36 patients with residual tumor diameters >1.5 cm. Patient age at diagnosis and extent of resection were independently associated with survival. Patients with MGMT promoter methylated tumors and complete resection made the best prognosis. Completeness of resection acts synergistically with concomitant and adjuvant radiochemotherapy, especially in patients with MGMT promoter methylation.

Cytoreductive surgery of glioblastoma as the key to successful adjuvant therapies: new arguments in an old discussion

BACKGROUND

This article discusses data from 3 randomized phase 3 trials, supporting a role for surgery in glioblastoma.

METHODS

Data were reviewed by extent of resection during primary surgery from the ALA-Glioma Study (fluorescence-guided versus conventional resection), the BCNU wafer study (BCNU wafer versus placebo), and the EORTC Study 26981-22981 (radiotherapy versus chemoradiotherapy with temozolomide).

RESULTS

For glioblastoma patients in the ALA study, median survival was 16.7 and 11.8 months for complete versus partial resection, respectively (P < 0.0001). Survival effects were maintained after correction for differences in age and tumor location. For glioblastoma patients who received ≥90% resection in the BCNU wafer study, median survival increased for BCNU wafer versus placebo (14.5 versus 12.4 months, respectively; P = 0.02), but no survival increase was found for <90% resection (11.7 versus 10.6 months, respectively; P = 0.98). In the EORTC study, absolute median gain in survival with chemoradiotherapy versus radiotherapy was greatest for complete resections (+4.1 months; P = 0.0001), compared with partial resections (+1.8 months; P = 0.0001), or biopsies (+1.5 months; P = 0.088), suggesting surgery enhanced adjuvant treatment.

CONCLUSION

Complete resection appears to improve survival and may increase the efficacy of adjunct/adjuvant therapies. If safely achievable, complete resection should be the surgical goal for glioblastoma.

Should we reoperate for recurrent high-grade astrocytoma?

Despite optimal treatment of post-operative radiotherapy and chemotherapy for newly diagnosed high-grade astrocytoma, nearly all patients eventually recur. However, the efficacy of reoperation for recurrent astrocytoma is still debatable as to different surgical indications. To investigate the therapeutic effect of reoperation on patients with recurrent high-grade astrocytoma more objectively, a retrospective case-matched study was carried out. The clinical data of 63 cases of recurrent high-grade astrocytoma treated between January 2006 and December 2008 were studied. A total of 21 cases received reoperation immediately after tumor recurrence, while 42 cases without reoperation were matched by gender, age, Karnofsky Performance Scale (KPS) score, histopathology, recurrent interval after the first operation, extent of initial surgery, adjuvant treatment and characteristics of recurrent tumor. The study showed that the median survival time was 7 months in the reoperation group, while in non-reoperation group, it was 4 months. There was significant difference on univariate analysis (P < 0.001). Moreover, the median duration time of progression-free survival (PFS) after tumor recurrence was significantly (P < 0.001) longer in the reoperation group (5 months) than that in the non-reoperation group (2.5 months). The prognostic factors of recurrent high-grade astrocytoma included reoperation, KPS score and tumor location. It was indicated that reoperation could prolong the survival time and improve the quality of survival in patients of recurrent high-grade astrocytoma.

Long-term survival with primary glioblastoma multiforme: a clinical study in bulgarian patients

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor with an extremely poor prognosis in spite of multimodal treatment approaches. The estimated median survival in cases with GBM is about 12–16 months. Those patients who survive =3 years after the initial diagnosis are defined as long-term survivors. In this study, we retrospectively analyze 50 consecutive cases of Bulgarian patients with newly diagnosed GBM surgically treated at our institution for a period of 1 year. Four of them survived for more than 36 months after the initial intervention. The histological re-examination revealed features typical of primary GBM in 3 of these cases, which are described in detail in the present paper. A brief review of the relevant literature is also given.

Investigation of blood perfusion and metabolic activity of brain tumours in adults by using 99mTc-methoxyisobutylisonitrile

OBJECTIVES

(i) To examine blood perfusion and metabolic activity of various brain tumours using radionuclide cerebral angiography (RCA) and single-photon emission tomography (SPET) after a single dose of Tc-methoxyisobutylisonitrile (MIBI). (ii) To examine if the inclusion of RCA can improve insight into the relative contribution of tumour perfusion to the uptake of MIBI shown by SPET, and to improve evaluation of tumour biology. (iii) To determine the value and the roles of MIBI in the management of brain tumour patients.

METHODS

Fifty adult patients (38 male, 12 female) with a total of 56 intracranial space-occupying lesions have been included prospectively, 37 of which were newly diagnosed and the remaining with signs of recurrence/rest of earlier resected and irradiated brain tumours. The control group consisted of nine volunteers with no evidence of organic cerebral disease. Scintigraphic examination consisted of a dynamic first-pass study lasting 60 s (3 s/frame) and two SPET studies (60 projections each, 25 s/projection), starting 15 min and 2 h after intravenous injection of MIBI. Regions of interest of the tumour and normal brain tissue were drawn on RCA and both early and delayed SPET slices. The following tumour/brain activity ratios have been calculated: (i) tumour perfusion index (P); (ii) early uptake index (E); (iii) delayed uptake index (D); and(iv) retention index (R). Analogous indices have been calculated from the same examinations performed in controls, reflecting maximal physiologic regional variations of perfusion and uptake in brain tissue.

RESULTS

Mean P of various brain tumours (low-grade gliomas 0.98, anaplastic gliomas 1.14, glioblastoma multiforme 1.20, metastases 1.09, lymphomas 1.08) differ little from each other and do not exceed maximal physiologic regional variations of cerebral perfusion (1.33), with the exception of meningioma (1.87, F=2.83, P=0.015). The receiver operating characteristics curve analysis of P showed that for the cut-off value of 1.45 the sensitivity for distinguishing meningioma from other tumours is 75%, specificity 87%, positive predictive value 33% and negative predictive value 97%. Mean E of malignant brain tumours (8.3, n=31, 23 primary, eight secondary), except anaplastic gliomas (3.5, n=5), differed significantly (P=0.02) from those of benign gliomas (3, n=9) but not from that of meningioma (11.9, n=4). The cut-off value for distinguishing malignant from benign lesions on the basis of E set at 4.8 resulted in sensitivity 67%, specificity 75%, accuracy 70%, positive predictive value 80% and negative predictive value 60%. D and R showed tendency of wash-out of MIBI from meningiomas, but otherwise did not improve the results substantially.

CONCLUSION

Integrated results of RCA and SPET with Tc-MIBI indicate that blood perfusion, blood-tumour barrier permeability and metabolic activity of the tumour are all very important for the resultant uptake shown by SPET. If the perfusion index is less than 1.45, then meningioma can be ruled out. Early SPET is recommendable for distinguishing glioblastoma from low-grade gliomas, as a complement to standard magnetic resonance imaging and/or computed tomography.

Imaging features of invasion and preoperative and postoperative tumor burden in previously untreated glioblastoma: Correlation with survival

BACKGROUND

A paucity of data exists concerning the prognostic usefulness of preoperative and postoperative imaging after resection of glioblastoma multiforme (GBM). This study aimed to connect outcome with imaging features of GBM.

METHODS

Retrospective computer-assisted volumetric calculations quantified central necrotic (T0), gadolinium-enhanced (T1) and increased T2-weighted signal volumes (T2) in 70 patients with untreated GBM. Clinical and treatment data, including extent of resection (EOR), were obtained through chart review. T1 volume was used as a measure of solid tumor burden; and T2 volume, as an indicator of invasive isolated tumor cell (ITC) burden. Indicators of invasiveness included T2:T1 ratios as a propensity for ITC infiltration compared to solid tumor volumes and qualitative analysis of subependymal growth and infiltration of the basal ganglia, corpus callosum or brainstem. Cox multivariate analysis (CMVA) was used to identify significant associations between imaging features and survival.

RESULTS

In the 70 patients studied, significant associations with reduced survival existed for gadolinium-enhancing tumor crossing the corpus callosum (odds ratio, 3.14) and with increased survival with gross total resection (GTR) (GTR median survival, 62 weeks versus 37 and 34 weeks for sub-total resection and biopsy, respectively). For a selected "GTR-eligible" subgroup of 52 patients, prolonged survival was associated with smaller preoperative gadolinium-enhancing volume (T1) and actual GTR.

CONCLUSION

Some magnetic resonance (MR) imaging indicators of tumor invasiveness (gadolinium-enhancing tumor crossing the corpus callosum) and tumor burden (GTR and preoperative T1 volume in GTR-eligible subgroup) correlate with survival. However, ITC-infiltrative tumor burden (T2 volume) and "propensity" for ITC invasiveness (T2:T1 ratio) did not impact survival. These results indicate that while the ITC component is the ultimate barrier to cure for GBM, the pattern of spread and volumes of gadolinium-enhancing solid tumor are more robust indicators of prognosis.

Survival and outcome of neurosurgical patients requiring ventilatory support after intensive care unit stay

OBJECTIVE

The aim of this study was to analyze the clinical outcome of severely ill neurosurgical patients whose need for artificial life support was extended. We sought to determine whether these patients benefit from extended treatment both in life expectancy and quality of life. Furthermore, we evaluated the direct cost of the neurosurgical treatment.

METHODS

The study group comprised a consecutive series of 346 neurosurgical patients in poor condition who were discharged from the intensive care unit but still in need of artificial respiratory support. The patients had various neurosurgical diagnoses and were treated between 2000 and 2003 at the Department of Neurosurgery, Helsinki University Central Hospital. We followed the outcome of these patients by specially formatted questionnaires 6 months and 1, 2, and 5 years after treatment. Their health-related quality of life was evaluated with EuroQol EQ-5D; quality-adjusted life years (QALY) gained with the treatment and the costs of a QALY were calculated.

RESULTS

The median follow-up time was 5 years. The mortality rate was 27% at 30 days, 45% at 1 year, and 59% at 5 years after treatment. Of the patients, 20% had a good recovery (Glasgow Outcome Scale [GOS] scores 4 and 5), 18% had severe disability (GOS score 3), none was in a vegetative state (GOS score 2), 59% were dead (GOS score 1), and 3% were lost to follow-up. Of the survivors, 69% lived at home, 22% in a nursing home, 2% were in a hospital, and 7% were lost to follow-up. The median EQ-5D index value was lower than the median index value for the general population: 0.71 (25th percentile [Q1] 0.38 and 75th percentile [Q3] 0.85) versus 0.85 (Q1 0.73 and Q3 1.00). The median cost of the direct neurosurgical treatment per patient was 15,000 euros (25th percentile, 10,000 euros 75th percentile, 22,000 euros). Surviving patients gained a mean of 17 +/- 13 QALYs. The cost of 1 QALY was 2521 euros.

CONCLUSION

Prolonged intensive care unit and step-down unit treatment of critically ill neurosurgical patients seems to be clinically justified. Moreover, direct costs of neurosurgical treatment were reasonably low.

Deficits in Japanese word spelling as an initial language symptom of malignant glioma in the left hemisphere

BACKGROUND

A good performance status at diagnosis is a prognostic factor in patients with malignant glioma whose median survival is 24 months. As early diagnosis may improve their poor prognosis, we looked for currently unknown initial symptoms among patients in good performance status.

METHODS

We chose 17 consecutive patients with malignant glioma in the left frontal and/or temporal lobe whose Karnofsky Performance Status was more than 80. At preoperative evaluation, we administered the Japanese version of the Western Aphasia Battery.

RESULTS

The chief complaint was difficulty in speech (n = 6), headache/nausea (n = 4), seizures (n = 5), and uncinate fits (n = 1); one patient was symptom-free. Of the 17 patients, 14 exhibited no motor deficits. In 15 patients, the aphasia quotient exceeded 80, indicating that the overall language deficits were mild. However, in the reading section, their scores on the "spelled kanji (Japanese ideogram) recognition" test (full score = 10) were selectively low (5.3 +/- 1.6 for right-handed individuals with frontal lesions, 6.1 +/- 1.0 for right-handed patients with temporal lesions, 7.2 +/- 2.0 for left-handed/bimanual individuals with frontal/temporal lesions). Their scores on the "spelling kanji" test were 3.0 +/- 1.6, 4.8 +/- 1.2, and 9.4 +/- 0.6, respectively.

CONCLUSIONS

Our findings point to the importance of recognizing spelling deficits as an initial symptom of left hemisphere glioma in efforts to identify patients in good performance status whose prognosis may be improved. It would be important to determine if the spelling of alphabetic words is also impaired early in the clinical course of left hemisphere glioma.

Nomograms for predicting survival of patients with newly diagnosed glioblastoma: prognostic factor analysis of EORTC and NCIC trial 26981-22981/CE.3

BACKGROUND

A randomised trial published by the European Organisation for Research and Treatment of Cancer (EORTC) and the National Cancer Institute of Canada (NCIC) Clinical Trials Group (trial 26981-22981/CE.3) showed that addition of temozolomide to radiotherapy in the treatment of patients with newly diagnosed glioblastoma significantly improved survival. We aimed to undertake an exploratory subanalysis of the EORTC and NCIC data to confirm or identify new prognostic factors for survival in adult patients with glioblastoma, derive nomograms that predict an individual patient's prognosis, and suggest stratification factors for future trials.

METHODS

Data from 573 patients with newly diagnosed glioblastoma who were randomly assigned to radiotherapy alone or to the same radiotherapy plus temozolomide in the EORTC and NCIC trial were included in this subanalysis. Survival modelling was done in three patient populations: intention-to-treat population of all randomised patients (population 1); patients assigned temozolomide and radiotherapy (population 2, n=287); and patients assigned temozolomide and radiotherapy who had assessment of MGMT promoter methylation status and who had undergone tumour resection (population 3, n=103). Cox proportional hazards models were fitted with and without O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status. Nomograms were developed to predict an individual patient's median and 2-year survival probabilities. No nomogram was developed in the radiotherapy-alone group because combined treatment is now the new standard of care.

FINDINGS

Independent of the MGMT promoter methylation status, analysis in all randomised patients (population 1) identified combined treatment with temozolomide, more extensive tumour resection, younger age, Mini-Mental State Examination (MMSE) score of 27 or higher, and no corticosteroid treatment at baseline as independent prognostic factors correlated with improved survival outcome. In patients assigned temozolomide and radiotherapy (population 2), younger age, better performance status, more extensive tumour resection, and MMSE score of 27 or higher were associated with better survival. In patients who had tumours resected, who were assigned temozolomide and radiotherapy, and who had available MGMT promoter methylation status (population 3), methylated MGMT, better performance status, and MMSE score of 27 or higher were associated with improved survival. Nomograms were developed and are available at http://www.eortc.be/tools/gbmcalculator.

INTERPRETATION

MGMT promoter methylation status, age, performance status, extent of resection, and MMSE are suggested as eligibility or stratification factors for future trials in patients with newly diagnosed glioblastoma. Stratifying by MGMT promoter methylation status should be mandatory in all glioblastoma trials that use alkylating chemotherapy. Nomograms can be used to predict an individual patient's prognosis, and they integrate pertinent molecular information that is consistent with a paradigm shift towards individualised patient management.

A mathematical modelling tool for predicting survival of individual patients following resection of glioblastoma: a proof of principle

The prediction of the outcome of individual patients with glioblastoma would be of great significance for monitoring responses to therapy. We hypothesise that, although a large number of genetic-metabolic abnormalities occur upstream, there are two ‘final common pathways’ dominating glioblastoma growth – net rates of proliferation (ρ) and dispersal (D). These rates can be estimated from features of pretreatment MR images and can be applied in a mathematical model to predict tumour growth, impact of extent of tumour resection and patient survival. Only the pre-operative gadolinium-enhanced T1-weighted (T1-Gd) and T2-weighted (T2) volume data from 70 patients with previously untreated glioblastoma were used to derive a ratio D/ρ for each patient. We developed a ‘virtual control’ for each patient with the same size tumour at the time of diagnosis, the same ratio of net invasion to proliferation (D/ρ) and the same extent of resection. The median durations of survival and the shapes of the survival curves of actual and ‘virtual’ patients subjected to biopsy or subtotal resection (STR) superimpose exactly. For those actually receiving gross total resection (GTR), as shown by post-operative CT, the actual survival curve lies between the ‘virtual’ results predicted for 100 and 125% resection of the T1-Gd volume. The concordance between predicted (virtual) and actual survivals suggests that the mathematical model is realistic enough to allow precise definition of the effectiveness of individualised treatments and their site(s) of action on proliferation (ρ) and/or dispersal (D) of the tumour cells without knowledge of any other clinical or pathological information.

Prognostic markers of astrocytoma: how to predict the unpredictable?

Astrocytomas are the most frequent tumors originating in the human nervous system. They carry a dismal prognosis as high-grade astroctyoma patients (World Health Organization [WHO] grade III and IV) rarely live beyond 5 years. At present, these tumors are mainly diagnosed through the difficult task of histologic examination of tissue obtained through stereotactic biopsy or tumor resection. In addition to determining the malignancy grade through histologic studies, the only other prognostic factors used in clinical setting are patient age and performance status. To overcome current limitations, research is underway to develop molecular approaches for glioma classification. These include identification, characterization and expansion of clinical (patient characteristics and imaging variables), histologic (WHO classification criteria) and molecular (genetic and proteomic) factors with prognostic potential. In this review the established classification characteristics, along with recent advances that may lead to the addition of new parameters and thus improve patient management and survival, are discussed.

Application of the Naïve Bayesian Classifier to optimize treatment decisions

BACKGROUND AND PURPOSE

To study the accuracy, specificity and sensitivity of the Naïve Bayesian Classifier (NBC) in the assessment of individual risk of cancer relapse or progression after radiotherapy (RT).

MATERIALS AND METHODS

Data of 142 brain tumour patients irradiated from 2000 to 2005 were analyzed. Ninety-six attributes related to disease, patient and treatment were chosen. Attributes in binary form consisted of the training set for NBC learning. NBC calculated an individual conditional probability of being assigned to: relapse or progression (1), or no relapse or progression (0) group. Accuracy, attribute selection and quality of classifier were determined by comparison with actual treatment results, leave-one-out and cross validation methods, respectively. Clinical setting test utilized data of 35 patients. Treatment results at classification were unknown and were compared with classification results after 3 months.

RESULTS

High classification accuracy (84%), specificity (0.87) and sensitivity (0.80) were achieved, both for classifier training and in progressive clinical evaluation.

CONCLUSIONS

NBC is a useful tool to support the assessment of individual risk of relapse or progression in patients diagnosed with brain tumour undergoing RT postoperatively.

Targeted delivery of antitumoral therapy to glioma and other malignancies with synthetic chlorotoxin (TM-601)

Targeted therapies for cancer is a rapidly advancing field, but the identification of tumor-specific ligands has proven difficult. Chlorotoxin (CTX) is a small, 36 amino acid neurotoxin isolated from the venom of the Giant Yellow Israeli scorpion Leiurus Quinquestriatus. Interestingly, the peptide has been found to preferentially bind to a variety of human malignancies, but shows little or no binding to normal human tissues. A synthetic version of this peptide (TM-601) has been manufactured and covalently linked to iodine 131 (131I-TM-601) as a means of targeting radiation to tumor cells. Preclinical studies and Phase I clinical trials have been completed in patients with recurrent glioma, a type of malignant brain tumor. These studies demonstrated that intracavitary dosing of 131I-TM-601 appears safe, minimally toxic, and binds malignant glioma with high affinity and for long durations. A Phase II trial of this agent using higher doses of radioactivity and repeated local administrations is underway. In addition, enrolment has begun in a Phase I trial evaluating whether systemically delivered 131I-TM-601 can be used to image metastatic solid tumors and primary gliomas. Due to its small size, selective tumor binding properties, minimal toxicity and relative ease of manipulation, CTX represents a potentially important targeting agent for many cancers.

A prospective study of quality of life in adults with newly diagnosed high-grade gliomas: the impact of the extent of resection on quality of life and survival

OBJECTIVE

To describe the quality of life (QOL) over time for adults with newly diagnosed high-grade gliomas and to examine the relationship between QOL and outcome data collected in three prospective cooperative group clinical trials.

METHODS

The QOL study was a companion protocol for three Phase II high-grade glioma protocols. Five self-administered forms were completed by patients to assess QOL at study entry, 2 months, and 4 months after enrollment.

RESULTS

QOL data were available for baseline, first, and second subsequent follow-up evaluations for 89%, 71%, and 69% of patients, respectively. A significant proportion of patients (47.1%) experienced impaired QOL (QOL < or = 50) in at least one measure at subsequent evaluations, whereas most patients (88%) with impaired QOL at baseline continued to have impaired QOL at subsequent evaluations. On multivariable analyses, baseline QOL measures were predictive of QOL at the time of follow-up. In addition, patients who underwent a gross total resection were much less likely to have impaired QOL (P = 0.006), were less likely to experience worsening depression (P = 0.0008), and were more likely to have improved QOL (P = 0.003) at their first follow-up evaluation. Changes in QOL measures over time were not found to be associated with survival in multivariable analyses that adjusted for known prognostic variables; variables that were independently associated with improved survival were better performance status (P < 0.001), younger age (P < 0.001), and greater extent of resection (P < 0.001).

CONCLUSION

Baseline QOL was predictive of QOL over time. Gross total resection was associated with longer survival and improved QOL over time for patients with high-grade gliomas.

Bromophenol blue staining of tumors in a rat glioma model

OBJECTIVE

For patients with gliomas, decreasing the tumor burden with macroscopic surgical resection may affect quality of life, time to tumor progression, and survival. Injection of bromophenol blue (BPB) may enhance intraoperative visualization of an infiltrating tumor and its margins and improve the extent of resection. In this study, we investigated the uptake of BPB in experimental rat brain tumors.

METHODS

We first conducted a toxicity study with bolus intravenous injections of 5, 60, and 360 mg/kg doses of BPB in nontumor-bearing Fischer 344 rats. No adverse effects were observed in any of the animals during the 60 day observation period. We then injected 9L tumor cells intracerebrally into Fischer 344 rats and approximately 2 weeks later, administered a bolus intravenous injection of 5 to 360 mg/kg BPB. Fifteen minutes after BPB injection, we sacrificed the animals and removed their brains. In a subsequent study, we injected 180 mg/kg BPB and sacrificed animals at several time points to monitor tumor staining over time.

RESULTS

The stain was clearly visible and localized to the tumor for all BPB concentrations 60 mg/kg or greater, and in an additional experiment, we found that tumor staining persisted for at least 8 hours after BPB injection.

CONCLUSION

We conclude that BPB helped visualize experimental tumors at time points from a few minutes to several hours after injection. Because BPB also proved to be nontoxic to the animals at effective concentrations, we believe the compound may be potentially useful in helping neurosurgeons visualize brain tumors in humans.

Intra-operative 3D ultrasound in neurosurgery

In recent years there has been a considerable improvement in the quality of ultrasound (US) imaging. The integration of 3D US with neuronavigation technology has created an efficient and inexpensive tool for intra-operative imaging in neurosurgery. In this review we present the technological background and an overview of the wide range of different applications. The technology has so far mostly been applied to improve surgery of tumours in brain tissue, but it has also been found to be useful in other procedures such as operations for cavernous haemangiomas, skull base tumours, syringomyelia, medulla tumours, aneurysms, AVMs and endoscopy guidance.

The treatment of malignant gliomas

The optimal management of patients with malignant gliomas begins with the accurate determination of the pathologic diagnosis based on adequate sampling of the tumor. Clear differences in prognosis and therapeutic options have been established for the various tumor grades and cellular classification. Current recommendations, on the basis of the results of a recent phase III randomized trial, are that patients with glioblastoma should have maximal surgical resection followed by concurrent radiation and chemotherapy with temozolomide. It is further recommended that patients then be treated with 6 to 12 months of adjuvant temozolomide. However, despite the shown improvement in survival with this chemoradiation regimen, the impact on outcome is modest. It is increasingly evident that a greater understanding of the molecular mechanisms of gliomagenesis is needed to improve treatments for these patients. Recent and ongoing investigations strongly indicate that specific molecular markers tremendously impact prognosis and often can predict response to treatment. For example, allelic loss of the 1p and 19q chromosome arms predicts a dramatic improvement in response to treatment and survival for tumors histologically classified as anaplastic oligodendroglioma. Future advances for treating primary brain tumors likely will be directly related to our ability to molecularly subcategorize tumors and customize therapy based on the molecular profile within each histologic type and grade of tumor. This is evident in preliminary data indicating that inactivation of the methyl guanine methyltransferase gene by hypermethylation of the promoter region specifically predicts a better tumor response rate to chemotherapies that alkylate DNA as their mechanism of action. Similarly, elucidation of overly active signal transduction pathways within tumor cells may provide an opportunity to select the optimal therapeutic regimen composed of modulators of these pathways, analogous to restricting the use of trastuzumab to breast cancers expressing the Her-2 receptor. Advances in treating primary malignant brain tumors will likely depend on collaborative clinical trials that are designed to select patients on the basis of histologic and molecular characteristics and to determine the optimal biologic dose of the best agent that can treat each specific tumor type.