Pretreatment factors predict overall survival for patients with low-grade glioma: a recursive partitioning analysis

Sex-Specific Differences in Low Grade Glioma Presentation and Outcome

PURPOSE

In addition to established prognostic factors in low-grade glioma (LGG), studies suggest a sexual dimorphism with male sex portending worse prognosis. Our objective was to identify the impact of sex on presentation and outcomes in LGG.

METHODS

We conducted a retrospective cohort study of adults (aged ≥ 18 years) diagnosed with LGG (WHO 2016 grade 2 glioma). Patients with IDH wildtype tumors were excluded. Patients were matched between male and female sex by age, treatment, and surgery via propensity score matching. Patient, tumor, and treatment characteristics were analyzed by sex. Endpoints included overall survival (OS), next intervention free survival (NIFS), progression free survival (PFS), and malignant transformation free survival (MTFS). Kaplan Meier analyses and Cox proportional hazards regression multivariable analysis (MVA) with backwards elimination was completed.

RESULTS

Of the 532 patients identified, 258 (48%) were male. Males were more likely to present with seizure (69.38% vs. 56.57%, p = 0.002), but no other statistically significant differences between sexes at presentation were identified. 5-year OS was higher in females at 87% (95% CI 83%-91%) versus 78% (95% CI 73-84%) in males (p=0.0045). NIFS was significantly higher in female patients at 68% (95% CI 62-74%) versus 57% (95% CI 51%-64%) in males (p = 0.009). On MVA, female sex was independently associated with improved OS (HR 1.54, 95% CI 1.16-2.05; p= 0.002), NIFS (HR 1.42, 95% CI 1.42; p= 0.004), and MTFS (HR 1.62, 95% CI 1.24-2.12; p= 0.0004). In patients with molecularly defined LGG (IDH and 1p19q status) (n = 291), female sex remained independently associated with improved OS (HR 1.79, 95% CI 1.16-2.77; p = 0.008) and NIFS (HR 1.45, 95% CI 1.07-1.96; p = 0.016).

CONCLUSIONS

In this study, female sex was independently associated with improved outcomes. These findings support intrinsic sex-specific differences in LGG behavior, justifying further studies to optimize management and therapeutics based on sex.

Development and validation of a novel survival prediction model for newly diagnosed lower-grade gliomas

OBJECTIVE

Diffuse gliomas are the most common primary gliomas with a poor prognosis. This study aimed to develop and validate prognostic models for predicting the survival probability in newly diagnosed lower-grade glioma (LGG) patients.

METHODS

Detailed data were obtained for newly diagnosed LGG from The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) cohorts. Survival was assessed using Cox proportional hazards regression with adjustment for known prognostic factors. The model was established using the TCGA cohort, and independently validated using the CGGA cohort, to predict the 3-, 5-, and 10-year survival probabilities of patients.

RESULTS

Data from 293 patients with newly diagnosed LGG from the TCGA cohort were used to establish a prognostic model, and from 232 patients with primary LGG in the CGGA cohort to validate the model. Age, tumor grade, molecular subtype, tumor resection, and preoperative neurological deficits were included in the prediction model. The Cox regression model had a satisfactory corrected concordance index of 0.8508, 0.8510, and 0.8516 in the internal bootstrap validation at 3, 5, and 10 years, respectively. The calibration plots demonstrated high consistency of the predicted and observed outcomes. The CGGA cohort was used for external validation and showed satisfactory discrimination of 0.7776, 0.7682, and 0.7051 at 3, 5, and 10 years, respectively. The calibration plots demonstrated an acceptable calibration capability in the external validation.

CONCLUSIONS

This study established and validated a prognostic model to predict the survival probability of patients with newly diagnosed LGG. The model performed well in discrimination and calibration with ease of use, speed, accessibility, interpretability, and generalizability. An easily used nomogram based on the Cox model was established for clinical application. Moreover, a free, easy-to-use software interface based on the nomogram is provided online.

Prediagnosis epilepsy and survival in patients with glioma: a nationwide population-based cohort study from 2009 to 2018

OBJECTIVE

Considering that epilepsy is common, and knowledge is lacking on its role especially for the prognosis of high-grade gliomas, the objective of this study was to investigate the association between epilepsy prior to glioma diagnosis and survival among glioma patients.

METHODS

In a nationwide population-based cohort study, we included 3763 adult glioma patients diagnosed between 2009 and 2018 according to the Danish Neuro-Oncology Registry. Information on epilepsy was redeemed through Danish Neuro-Oncology Registry, National Patient Registry, and National Prescription Registry. Cox proportional hazard models with 95% confidence intervals (CIs) were applied to examine hazard ratios (HRs) for the association between epilepsy (< 1 year prior to glioma including epilepsy at onset; 1-10 years prior to glioma; no prior epilepsy) and risk of death, and whether it differed according to tumor grade and size, performance status, and treatment modalities.

RESULTS

A 32% decreased risk of death in patients with epilepsy within 1 year prior to glioma compared to no prior epilepsy was found (HR = 0.68; CI 0.63-0.75). A favorable prognosis was seen for epilepsy in all glioma grades: II (HR = 0.55; CI 0.39-0.77), III (HR = 0.59; CI 0.48-0.73), and IV (HR = 0.85; CI 0.77-0.94).

CONCLUSIONS

Patients with epilepsy within 1 year prior to glioma diagnosis had significant survival benefits compared to patients with no prior epilepsy. This association was significant for both low-grade gliomas (grade II) and high-grade gliomas (grade III and IV). Survival benefits in glioma patients with epilepsy at onset are possibly primarily attributable to tumor-specific histopathology, molecular biomarkers, and early diagnosis.

Evaluating survival in subjects with astrocytic brain tumors by dynamic susceptibility-weighted perfusion MR imaging

Purpose

Studies have evaluated the application of perfusion MR for predicting survival in patients with astrocytic brain tumors, but few of them statistically adjust their results to reflect the impact of the variability of treatment administered in the patients. Our aim was to analyze the association between the perfusion values and overall survival time, with adjustment for various clinical factors, including initial treatments and follow-up treatments.

Materials and methods

This study consisted of 51 patients with astrocytic brain tumors who underwent perfusion-weighted MRI with MultiHance® at a dose of 0.1 mmol/kg prior to initial surgery. We measured the mean rCBV, the 5% & 10% maximum rCBV, and the variation of rCBV in the tumors. Comparisons were made between patients with and without 2-year survival using two-sample t-test or Wilcoxon rank-sum test for the continuous data, or chi-square and Fisher exact tests for categorical data. The multivariate cox-proportional hazard regression was fit to evaluate the association between rCBV and overall survival time, with adjustment for clinical factors.

Results

Patients who survived less than 2 years after diagnosis had a higher mean and maximum rCBV and a larger variation of rCBV. After adjusting for clinical factors including therapeutic measures, we found no significant association of overall survival time within 2 years with any of these rCBV values.

Conclusions

Although patients who survived less than 2 years had a higher mean and maximum rCBV and a larger variation of rCBV, rCBV itself may not be used independently for predicting 2-year survival of patients with astrocytic brain tumors.

Current clinical management of elderly patients with glioma

INTRODUCTION

The incidence of gliomas is increasing in elderly patients. Clinical factors, such as age, performance status, and comorbidities contribute when choosing adequate treatment in older patients.

AREAS COVERED

This review covers the main pathological and molecular features of gliomas in elderly patients, as well as the neurological and geriatric assessment to select patients for surgery and antineoplastic treatments. The results from the most relevant clinical trials in both lower-grade (LGGs) and high-grade gliomas (HGGs) are reviewed.

EXPERT OPINION

Different clinical and biological factors need to be integrated into prognostic scales in order to better stratify the elderly population. Both Stupp and Perry regimens can be proposed to fit patients with GBM aged < 70 years. Conversely, for patients aged ≥ 70 years, the Perry regimen should be preferred. For unfit and frail patients, temozolomide alone when MGMT is methylated or hypofractionated RT alone when MGMT is unmethylated, are the optimal choice. Few data are available regarding the optimal management of elderly patients with LGGs. The benefit of an extensive resection and presence of methylation of the MGMT promoter need to be further investigated to confirm their role in improving the OS.

Italian consensus and recommendations on diagnosis and treatment of low-grade gliomas. An intersociety (SINch/AINO/SIN) document

In 2018, the SINch (Italian Society of Neurosurgery) Neuro-Oncology Section, AINO (Italian Association of Neuro-Oncology) and SIN (Italian Association of Neurology) Neuro-Oncology Section formed a collaborative Task Force to look at the diagnosis and treatment of low-grade gliomas (LGGs). The Task Force included neurologists, neurosurgeons, neuro-oncologists, pathologists, radiologists, radiation oncologists, medical oncologists, a neuropsychologist and a methodologist. For operational purposes, the Task Force was divided into five Working Groups: diagnosis, surgical treatment, adjuvant treatments, supportive therapies, and follow-up. The resulting guidance document is based on the available evidence and provides recommendations on diagnosis and treatment of LGG patients, considering all aspects of patient care along their disease trajectory.

Prediction of IDH Status Through MRI Features and Enlightened Reflection on the Delineation of Target Volume in Low-Grade Gliomas

Isocitrate dehydrogenase mutational status defines distinct biologic behavior and clinical outcomes in low-grade gliomas. We sought to determine magnetic resonance imaging characteristics associated with isocitrate dehydrogenase mutational status to evaluate the predictive roles of magnetic resonance imaging features in isocitrate dehydrogenase mutational status and therefore their potential impact on the determination of clinical target volume in radiotherapy. Forty-eight isocitrate dehydrogenase-mutant and 28 isocitrate dehydrogenase–wild-type low-grade gliomas were studied. Isocitrate dehydrogenase mutation was related to more frequency of cortical involvement compared to isocitrate dehydrogenase–wild-type group (34/46 vs 6/24, P = .0001). Peritumoral edema was less frequent in isocitrate dehydrogenase–mutant tumors (32.6% vs 58.3% for isocitrate dehydrogenase–wild-type tumors, P = .0381). Isocitrate dehydrogenase–wild-type tumors were more likely to have a nondefinable border, while isocitrate dehydrogenase–mutant tumors had well-defined borders (66.7% vs 39.1%, P = .0287). Only 8 (17.4%) of 46 of the isocitrate dehydrogenase–mutant tumors demonstrated marked enhancement, while this was 66.7% in isocitrate–wild-type tumors (P < .0001). Choline–creatinine ratio for isocitrate dehydrogenase–wild-type tumors was significantly higher than that for isocitrate dehydrogenase–mutant tumors. In conclusion, frontal location, well-defined border, cortical involvement, less peritumoral edema, lack of enhancement, and low choline–creatinine ratio were predictive for the definition of isocitrate dehydrogenase–mutant low-grade gliomas. Magnetic resonance imaging can provide an advantage in the detection of isocitrate dehydrogenase status indirectly and indicate the need to explore new design for treatment planning in gliomas. Choline–creatinine ratio in magnetic resonance spectroscopy could be a potential more reasonable reference for the new design of delineation of target volume in low-grade gliomas.

Isocitrate Dehydrogenase Mutations in Low-Grade Gliomas Correlate With Prolonged Overall Survival in Older Patients

BACKGROUND

Older age has been associated with worse outcomes in low-grade gliomas (LGGs). Given their rarity in the older population, determining optimal treatment plans and patient outcomes remains difficult.

OBJECTIVE

To retrospectively study LGG survival outcomes in an older population stratified by molecular genetic profiles.

METHODS

We included patients age ≥40 yr with pathologically confirmed World Health Organization grade II gliomas treated at a single institution between 1995 and 2015. We collected tumor genomic information when available.

RESULTS

Median overall survival for the entire group (n = 111, median age 51 yr, range 40-77 yr) was 15.75 yr with 5- and 10-yr survival rates of 84.3% and 67.7%, respectively. On univariate analysis, patients with isocitrate dehydrogenase (IDH) mutation had significantly increased survival compared to IDH wildtype (hazard ratio [HR] 0.17 [0.07-0.45], P < .001). Older age, seizure at presentation, larger tumor size, IDH wildtype, biopsy only, chemotherapy, and radiation were significantly associated with shorter survival based on univariate analyses. In patients with known IDH status (n = 73), bivariate analysis of IDH mutation status and age showed only IDH status significantly influenced overall survival (HR 0.22 [0.07-0.68], P = .008). Greater surgical resection was predictive of survival, although extent of resection significantly correlated with IDH mutation status (odds ratio 7.5; P < .001).

CONCLUSION

We show that genomic alterations in LGG patients ≥40 occur at high rates like the younger population and predict a similar survival advantage. Maximizing surgical resection may have survival benefit, although feasibility of resection is often linked to IDH status. Given the importance of molecular genetics, a redefinition of prognostic factors associated with these tumors is likely to emerge.

Contrast-enhancement in supratentorial low-grade gliomas: a classic prognostic factor in the molecular age

BACKGROUND

Contrast enhancement (CE) is found in 10-60% of low-grade gliomas. Its prognostic significance is controversial, and its correlation with IDH mutations and 1p/19q codeletion is elusive. The aim of this study is to investigate whether CE is associated with molecular characteristics of low-grade gliomas and uncover its prognostic value.

MATERIALS AND METHODS

All confirmed histological cases of low-grade gliomas diagnosed at our institution between years 2000-2016 were reviewed (n = 102). Spinal and brainstem localization, only-biopsied tumours with ring-like enhancement and incomplete medical records were excluded.

RESULTS

Mean age was 42 years ( ± 13.9 years), and 63.6% were male. The median follow-up time was 79.8 months. CE was present on 25% of preoperative MRI, and 25% of patients were considered high-risk according to Pignatti score. Most were astrocytomas (67%) and 87.2% were surgically removed. IDH mutation was found in 64.6% of tumour samples, and 18.8% had a 1p/19q codeletion. No subgroup differences were observed according to CE except for presurgical performance status and postoperative chemotherapy. IDH status and 1p/19q codeletion were evenly distributed. On univariate analysis, age, size > 6 cm, CE, extent of resection, Pignatti score, IDH mutation and 1p/19q codeletion were significantly associated to OS. On multivariate analysis, only CE and IDH status were independently associated to OS. CE remained a significant prognostic factor in IDH-mutant non-codeleted tumours when analysed by tumour subtype.

CONCLUSION

CE in low-grade gliomas provides prognostic information in IDH-mutant non-codeleted tumours, although its meaning remains uncertain in IDH-wildtype gliomas.

Identification of potential biomarkers related to glioma survival by gene expression profile analysis

BACKGROUND

Recent studies have proposed several gene signatures as biomarkers for different grades of gliomas from various perspectives. However, most of these genes can only be used appropriately for patients with specific grades of gliomas.

METHODS

In this study, we aimed to identify survival-relevant genes shared between glioblastoma multiforme (GBM) and lower-grade glioma (LGG), which could be used as potential biomarkers to classify patients into different risk groups. Cox proportional hazard regression model (Cox model) was used to extract relative genes, and effectiveness of genes was estimated against random forest regression. Finally, risk models were constructed with logistic regression.

RESULTS

We identified 104 key genes that were shared between GBM and LGG, which could be significantly correlated with patients' survival based on next-generation sequencing data obtained from The Cancer Genome Atlas for gene expression analysis. The effectiveness of these genes in the survival prediction of GBM and LGG was evaluated, and the average receiver operating characteristic curve (ROC) area under the curve values ranged from 0.7 to 0.8. Gene set enrichment analysis revealed that these genes were involved in eight significant pathways and 23 molecular functions. Moreover, the expressions of ten (CTSZ, EFEMP2, ITGA5, KDELR2, MDK, MICALL2, MAP 2 K3, PLAUR, SERPINE1, and SOCS3) of these genes were significantly higher in GBM than in LGG, and comparing their expression levels to those of the proposed control genes (TBP, IPO8, and SDHA) could have the potential capability to classify patients into high- and low- risk groups, which differ significantly in the overall survival. Signatures of candidate genes were validated, by multiple microarray datasets from Gene Expression Omnibus, to increase the robustness of using these potential prognostic factors. In both the GBM and LGG cohort study, most of the patients in the high-risk group had the IDH1 wild-type gene, and those in the low-risk group had IDH1 mutations. Moreover, most of the high-risk patients with LGG possessed a 1p/19q-noncodeletion.

CONCLUSION

In this study, we identified survival relevant genes which were shared between GBM and LGG, and those enabled to classify patients into high- and low-risk groups based on expression level analysis. Both the risk groups could be correlated with the well-known genetic variants, thus suggesting their potential prognostic value in clinical application.

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.

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.

Evidence and context of use for contrast enhancement as a surrogate of disease burden and treatment response in malignant glioma

The use of contrast enhancement within the brain on CT or MRI has been the gold standard for diagnosis and therapeutic response assessment in malignant gliomas for decades. The use of contrast enhancing tumor size, however, remains controversial as a tool for accurately diagnosing and assessing treatment efficacy in malignant gliomas, particularly in the current, quickly evolving therapeutic landscape. The current article consolidates overwhelming evidence from hundreds of studies in the field of neuro-oncology, providing the necessary evidence base and specific contexts of use for consideration of contrast enhancing tumor size as an appropriate surrogate biomarker for disease burden and as a tool for measuring treatment response in malignant glioma, including glioblastoma.

Risk Factors for Malignant Transformation of Low-Grade Glioma

PURPOSE

The incidence, risk factors, and outcomes of low-grade glioma patients who undergo malignant transformation (MT) in the era of temozolomide are not well known. This study evaluates these factors in a large group of World Health Organization grade 2 glioma patients treated at a tertiary-care institution.

METHODS AND MATERIALS

Patient, tumor, and treatment factors were analyzed using an institutional review board-approved low-grade glioma database. Characteristics were compared using χ² and Wilcoxon signed rank tests. Time to event was summarized using proportional hazards models. Univariate and multivariate survival analyses were performed.

RESULTS

Of a total of 599 patients, 124 underwent MT; 76 (61.3%) had biopsy-proven MT. The MT incidence was 21%, and the median time to MT was 56.4 months. The 5- and 10-year progression-free survival rates were 30.6% ± 4.2% and 4.8% ± 1.9%, respectively, for MT patients and 60% ± 2.4% and 38% ± 2.7%, respectively, for non-MT patients. The 5- and 10-year overall survival rates were 75% ± 4.0% and 46% ± 5.0%, respectively, for MT patients and 87% ± 1.7% and 78% ± 2.3%, respectively, for non-MT patients. On multivariate analysis, older age (P = .001), male sex (P = .004), multiple tumor locations (P = .004), chemotherapy alone (P = .012), and extent of resection (P = .045) remained significant predictors of MT.

CONCLUSIONS

MT affects survival. Risk factors include older age, male sex, multiple tumor locations, use of chemotherapy alone, and presence of residual disease. Our finding that initial interventions could affect the rate of MT is provocative, but these data should be validated using data from prospective trials. In addition to improving survival, future therapeutic efforts should focus on preventing MT.

Is less more? Comparing chemotherapy alone with chemotherapy and radiation for high-risk grade 2 glioma: An analysis of the National Cancer Data Base

BACKGROUND

The addition of chemotherapy to adjuvant radiotherapy (chemotherapy and radiation therapy [CRT]) improves overall survival (OS) for patients with high-risk grade 2 gliomas; however, the impact of chemotherapy alone (CA) is unknown. This study compares the OS of patients with high-risk grade 2 gliomas treated with CA versus CRT.

METHODS

Patients with high-risk grade 2 gliomas (subtotal resection or age ≥ 40 years) with oligodendrogliomas, astrocytomas, or mixed tumors were identified with the National Cancer Data Base. Patients were grouped into CA and CRT cohorts. Univariate analyses and multivariate analyses (MVAs) were performed. Propensity score (PS) matching was also implemented. The Kaplan-Meier method was used to analyze OS.

RESULTS

A total of 1054 patients with high-risk grade 2 gliomas were identified: 496 (47.1%) received CA, and 558 (52.9%) received CRT. Patients treated with CA were more likely (all P values < .05) to have oligodendroglioma histology (65.5% vs 34.2%), exhibit a 1p/19q codeletion (22.8% vs 7.5%), be younger (median age, 47.0 vs 48.0 years), and receive treatment at an academic facility (65.2% vs 50.3%). The treatment type was not a significant predictor for OS (P = .125) according to the MVA; a tumor size > 6 cm, astrocytoma histology, and older age were predictors for worse OS (all P values < .05). After 1:1 PS matching (n = 331 for each cohort), no OS difference was seen (P = .696) between the CA and CRT cohorts at 5 (69.3% vs 67.4%) and 8 years (52.8% vs 56.7%).

CONCLUSIONS

No long-term OS difference was seen in patients with high-risk grade 2 gliomas treated with CA versus CRT. These findings are hypothesis-generating, and prospective clinical trials comparing these treatment paradigms are warranted. Cancer 2018;124:1169-78. © 2017 American Cancer Society.

The impact of adjuvant therapy for patients with high-risk diffuse WHO grade II glioma

Despite recent randomized, prospective evidence supporting use of RT and chemotherapy (CRT) for high-risk low-grade gliomas (LGG), many patients have historically received RT alone, chemotherapy alone or observation postoperatively. The purpose of this study is to evaluate outcomes for historical treatments in comparison to CRT for high-risk diffuse WHO grade II glioma patients. Records from 309 adults with WHO grade II glioma (1997-2008) eligible for RTOG 9802 (incomplete resection/biopsy or age ≥40 years) were retrospectively reviewed. Kaplan-Meier estimates were used for progression-free survival (PFS) and overall survival (OS). The Cox proportional hazards model was used for estimates of risk ratios for univariate and multivariate analyses. Median follow-up was 10.6 years. Adjuvant treatments included radiotherapy (RT) alone (45%), observation (31%), CRT (21%) and chemotherapy alone (3%). Non-astrocytic histology, TERT promoter mutation, 1p/19q codeletion and extensive resections were associated with improved PFS and OS on univariate analysis (all p < 0.05). IDH mutations and adjuvant CRT was associated with improved PFS (all p < 0.05). On multivariate analysis, histology, molecular grouping and extent of resection were significantly associated with PFS and OS. In addition, multivariate analysis revealed that CRT was associated with improved PFS and OS compared with RT alone, and improved PFS compared with observation. This study confirms the benefit of adding chemotherapy to RT compared with RT alone or observation. These findings emphasize the need for aggressive treatment in patients with high-risk LGG.

Patterns of care and treatment outcomes in older adults with low grade glioma: a 50-year experience

The purpose of this study was to identify changes in presentation, treatment and outcomes of older patients with low-grade glioma (LGG) over the past 50 years. 94 adults aged 55 or older upon diagnosis of a WHO grade II LGG at Mayo Clinic between 1960 and 2011 were included and grouped by those diagnosed before (group I: 1960-1989) and after (group II: 1990-2011) the routine use of post-operative MRI. Median follow-up was 11.4 years. Pathologic diagnoses included astrocytoma in 55%, mixed oligoastrocytoma in 18% and oligodendroglioma in 27%. Gross total resection (GTR) was achieved in 10%, radical subtotal resection (rSTR) in 6%, subtotal resection (STR) in 20% and biopsy only in 64%. Post-operative radiotherapy (PORT) was given in 77%. More patients in the modern era received GTR/rSTR (20 vs. 7%), though the difference was not statistically significant. Median progression-free survival (PFS) was 3.0 years, with 5- and 10-year PFS rates of 31 and 10%, respectively. Median, 5- and 10-year overall survival (OS) was 4.1 years, 43 and 17%, respectively. PFS and OS did not improve in the modern era. Factors negatively associated with PFS on multivariate analysis included astrocytoma histology, contrast enhancement and STR/biopsy. Factors associated with poor OS on multivariate analysis included astrocytoma histology, deep location, contrast enhancement and STR/biopsy. Despite reports of improving outcomes for younger patients treated in the modern era, outcomes have not significantly improved for older patients. Further efforts to improve outcomes based on molecular genotyping are needed to determine a rational strategy for treatment intensification.

Detecting tumor progression in glioma: current standards and new techniques

INTRODUCTION

The post-treatment monitoring of glioma patients remains an area of active research and development. Conventional imaging with MRI is a highly sensitive modality for detecting and monitoring primary and secondary brain tumors and includes multi-parametric sequences to better characterize the disease. Standardized schemes for measuring response to treatment are in wide clinical use; however, the introduction of new therapeutics have introduced new patterns of response that can confound interpretation of conventional MRI and can cause uncertainty in the proper management following therapy. Areas covered: A summary of current and evolving techniques for assessing glioma response in this era of new therapies that address these challenges are presented in this review. While this review focuses more on clinical and early clinical methodologies for MRI and nuclear medicine techniques some promising pre-clinical techniques are also presented. Expert commentary: While successful single institution results have been widely reported in the literature, any new methodologies must be undertaken in multi-center settings. Additionally, the need for standardization of protocols in quantitative measured are an important area that must be addressed for new and promising techniques to be implemented to a wide array of patients.

Progressive Low-Grade Glioma: Assessment of Prognostic Importance of Histologic Reassessment and MRI Findings

BACKGROUND

In patients with progressive low-grade glioma (LGG), the presence of new magnetic resonance imaging (MRI) enhancement is commonly used as an indicator of malignant degeneration, but its accuracy in this setting is uncertain.

OBJECTIVE

We characterize the ability of new MRI enhancement to serve as a surrogate for histologic grade in patients with progressive LGG, and to explore the prognostic value of new MRI enhancement, pathologic grade, and extent of resection.

METHODS

Patients at our institution with World Health Organization grade II glioma diagnosed between 1994 and 2010 and who underwent repeat biopsy or resection at progression were retrospectively reviewed (n = 108). The positive predictive value, negative predictive value, sensitivity, and specificity of new MRI enhancement were characterized. A multivariable proportional hazards model was used to test associations with overall survival (OS), and Kaplan-Meier curves were constructed to compare OS between patient subsets.

RESULTS

The positive predictive value, negative predictive value, sensitivity, and specificity of new MRI enhancement were 82%, 77%, 92%, and 57%, respectively. In patients without malignant degeneration, new MRI enhancement was associated with inferior median OS (92.5 months vs. not reached; P = 0.03). In patients with malignant degeneration, gross or near total resection was associated with improved median OS (58.8 vs. 28.8 months; P = 0.02).

CONCLUSION

In patients with progressive LGG, new MRI enhancement and pathologic grade were discordant in greater than 20% of cases. Pathologic confirmation of grade should therefore be attempted, when safe, to dictate management. Beyond functioning as a surrogate for pathologic grade, new MRI enhancement may predict for worse outcomes, a concept that merits prospective investigation.

Surgical approaches for the gliomas

Neurosurgical intervention remains the first step in effective glioma management. Mounting evidence suggests that cytoreduction for low- and high-grade gliomas is associated with a survival benefit. Beyond conventional neurosurgical principles, an array of techniques have been refined in recent years to maximize the effect of the neurosurgical oncologist and facilitate the impact of subsequent adjuvant therapy. With intraoperative mapping techniques, aggressive microsurgical resection can be safely pursued even when tumors occupy essential functional pathways. Other adjunct techniques, such as intraoperative magnetic resonance imaging, intraoperative ultrasonography, and fluorescence-guided surgery, can be valuable tools to safely reduce the tumor burden of low- and high-grade gliomas. Taken together, this collection of surgical strategies has pushed glioma extent of resection towards the level of cellular resolution.

The role of imaging in the management of adults with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline

QUESTION

What is the optimal imaging technique to be used in the diagnosis of a suspected low grade glioma, specifically: which anatomic imaging sequences are critical for most accurately identifying or diagnosing a low grade glioma (LGG) and do non-anatomic imaging methods and/or sequences add to the diagnostic specificity of suspected low grade gliomas?

TARGET POPULATION

These recommendations apply to adults with a newly diagnosed lesion with a suspected or histopathologically proven LGG.

RECOMMENDATION

LEVEL II

In patients with a suspected brain tumor, the minimum magnetic resonance imaging (MRI) exam should be an anatomic exam with both T2 weighted and pre- and post-gadolinium contrast enhanced T1 weighted imaging. CRITICAL IMAGING FOR THE IDENTIFICATION AND DIAGNOSIS OF LOW GRADE GLIOMA:

LEVEL II

In patients with a suspected brain tumor, anatomic imaging sequences should include T1 and T2 weighted and Fluid Attenuation Inversion Recovery (FLAIR) MR sequences and will include T1 weighted imaging after the administration of gadolinium based contrast. Computed tomography (CT) can provide additional information regarding calcification or hemorrhage, which may narrow the differential diagnosis. At a minimum, these anatomic sequences can help identify a lesion as well as its location, and potential for surgical intervention. IMPROVEMENT OF DIAGNOSTIC SPECIFICITY WITH THE ADDITION OF NON-ANATOMIC (PHYSIOLOGIC AND ADVANCED IMAGING) TO ANATOMIC IMAGING:

LEVEL II

Class II evidence from multiple studies and a significant number of Class III series support the addition of diffusion and perfusion weighted MR imaging in the assessment of suspected LGGs, for the purposes of discriminating the potential for tumor subtypes and identification of suspicion of higher grade diagnoses.

LEVEL III

Multiple series offer Class III evidence to support the potential for magnetic resonance spectroscopy (MRS) and nuclear medicine methods including positron emission tomography and single-photon emission computed tomography imaging to offer additional diagnostic specificity although these are less well defined and their roles in clinical practice are still being defined.

QUESTION

Which imaging sequences or parameters best predict the biological behavior or prognosis for patients with LGG?

TARGET POPULATION

These recommendations apply to adults with a newly diagnosed lesion with a suspected or histopathologically proven LGG.

RECOMMENDATION

Anatomic and advanced imaging methods and prognostic stratification

LEVEL III

Multiple series suggest a role for anatomic and advanced sequences to suggest prognostic stratification among low grade gliomas. Perfusion weighted imaging, particularly when obtained as a part of diagnostic evaluation (as recommended above) can play a role in consideration of prognosis. Other imaging sequences remain investigational in terms of their role in consideration of tumor prognosis as there is insufficient evidence to support more formal recommendations as to their use at this time.

QUESTION

What is the optimal imaging technique to be used in the follow-up of a suspected (or biopsy proven) LGG?

TARGET POPULATION

This recommendation applies to adults with a newly diagnosed low grade glioma.

RECOMMENDATIONS

LEVEL II

In patients with a diagnosis of LGG, anatomic imaging sequences should include T2/FLAIR MR sequences and T1 weighted imaging before and after the administration of gadolinium based contrast. Serial imaging should be performed to identify new areas of contrast enhancement or significant change in tumor size, which may signify transformation to a higher grade.

LEVEL III

Advanced imaging utility may depend on tumor subtype. Multicenter clinical trials with larger cohorts are needed. For astrocytic tumors, baseline and longitudinal elevations in tumor perfusion as assessed by dynamic susceptibility contrast perfusion MRI are associated with shorter time to tumor progression, but can be difficult to standardize in clinical practice. For oligodendrogliomas and mixed gliomas, MRS may be helpful for identification of progression.

The role of radiotherapy in the management of patients with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline

QUESTIONS

(1) What is the optimal role of external beam radiotherapy in the management of adult patients with newly diagnosed low-grade glioma (LGG) in terms of improving outcome (i.e., survival, complications, seizure control or other reported outcomes of interest)? (2) Which radiation strategies (dose, timing, fractionation, stereotactic radiation, brachytherapy, chemotherapy) improve outcomes compared to standard external beam radiation therapy in the initial management of low grade gliomas in adults? (3) Do specific factors (e.g., age, volume, extent of resection, genetic subtype) identify subgroups with better outcomes following radiation therapy than the general population of adults with newly diagnosed low-grade gliomas?

TARGET POPULATION

These recommendations apply to adults with newly diagnosed diffuse LGG.

RECOMMENDATIONS

OUTCOMES IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA TREATED WITH RADIOTHERAPY: Level I Radiotherapy is recommended in the management of newly diagnosed low-grade glioma in adults to prolong progression free survival, irrespective of extent of resection. Level II Radiotherapy is recommended in the management of newly diagnosed low grade glioma in adults as an equivalent alternative to observation in preserving cognitive function, irrespective of extent of resection. Level III Radiotherapy is recommended in the management of newly diagnosed low grade glioma in adults to improve seizure control in patients with epilepsy and subtotal resection. Level III Radiotherapy is recommended in the management of newly diagnosed low-grade glioma in adults to prolong overall survival in patients with subtotal resection. Level III Consideration of the risk of radiation induced morbidity, including cognitive decline, imaging abnormalities, metabolic dysfunction and malignant transformation, is recommended when the delivery of radiotherapy is selected in the management of newly diagnosed low-grade glioma in adults. STRATEGIES OF RADIOTHERAPY IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA: Level I Lower dose radiotherapy is recommended as an equivalent alternative to higher dose immediate postoperative radiotherapy (45-50.4 vs. 59.4-64.8 Gy) in the management of newly diagnosed low-grade glioma in adults with reduced toxicity. Level III Delaying radiotherapy until recurrence or progression is recommended as an equivalent alternative to immediate postoperative radiotherapy in the management of newly diagnosed low-grade glioma in adults but may result in shorter time to progression. Level III The addition of chemotherapy to radiotherapy is not recommended over whole brain radiotherapy alone in the management of low-grade glioma, as it provides no additional survival benefit. Level III Limited-field radiotherapy is recommended over whole brain radiotherapy in the management of low-grade glioma. Level III Either stereotactic radiosurgery or brachytherapy are recommended as acceptable alternatives to external radiotherapy in selected patients. PROGNOSTIC FACTORS IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA TREATED WITH RADIOTHERAPY: Level II It is recommended that age greater than 40 years, astrocytic pathology, diameter greater than 6 cm, tumor crossing the midline and preoperative neurological deficit be considered as negative prognostic indicators when predicting overall survival in adult low grade glioma patients treated with radiotherapy. Level II It is recommended that smaller tumor size, extent of surgical resection and higher mini-mental status exam be considered as positive prognostic indicators when predicting overall survival and progression free survival in patients in adult low grade glioma patients treated with radiotherapy. Level III It is recommended that seizures at presentation, presence of oligodendroglial histological component and 1p19q deletion (along with additional relevant factors-see Table 1) be considered as positive prognostic indicators when predicting response to radiotherapy in adults with low grade gliomas. Level III It is recommended that increasing age, decreasing performance status, decreasing cognition, presence of astrocytic histological component (along with additional relevant factors (see Tables 1, 2) be considered as negative prognostic indicators when predicting response to radiotherapy.

The role of surgery in the management of patients with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline

QUESTION

Should patients with imaging suggestive of low grade glioma (LGG) undergo observation versus treatment involving a surgical procedure?

TARGET POPULATION

These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma).

RECOMMENDATIONS

Surgical resection is recommended over observation to improve overall survival for patients with diffuse low-grade glioma (Level III) although observation has no negative impact on cognitive performance and quality of life (Level II).

QUESTION

What is the impact of extent of resection on progression free survival (PFS) or overall survival (OS) in LGG patients?

TARGET POPULATION

These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma).

RECOMMENDATIONS

IMPACT OF EXTENT OF RESECTION ON PFS:

LEVEL II

It is recommended that GTR or STR be accomplished instead of biopsy alone when safe and feasible so as to decrease the frequency of tumor progression recognizing that the rate of progression after GTR is fairly high.

IMPACT OF EXTENT OF RESECTION ON OS

LEVEL III

Greater extent of resection can improve OS in LGG patients.

QUESTION

What tools are available to increase extent of resection in LGG patients?

TARGET POPULATION

These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma).

RECOMMENDATIONS

INTRAOPERATIVE MRI DURING SURGERY:

LEVEL III

The use of intraoperative MRI should be considered as a method of increasing the extent of resection of LGGs.

QUESTION

What is the impact of surgical resection on seizure control and accuracy of pathology in low grade glioma patients?

TARGET POPULATION

These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma).

RECOMMENDATIONS

SURGICAL RESECTION AND SEIZURE CONTROL:

LEVEL III

After taking into account the patient's clinical status and tumor location, gross total resection is recommended for patients with diffuse LGG as a way to achieve more favorable seizure control.

ACCURACY OF DIAGNOSIS

LEVEL III

Taking into account the patient's clinical status and tumor location, surgical resection should be carried out to maximize the chance of accurate diagnosis.

QUESTION

What tools can improve the safety of surgery for LGGs in eloquent locations?

TARGET POPULATION

These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma).

RECOMMENDATIONS

PREOPERATIVE IMAGING:

LEVEL III

It is recommended that preoperative functional MRI and diffusion tensor imaging be utilized in the appropriate clinical setting to improve functional outcome after surgery for LGG.

INTRAOPERATIVE MAPPING OF TUMORS IN ELOQUENT AREAS

LEVEL III

Intraoperative mapping is recommended for patients with diffuse LGGs in eloquent locations compared to patients with non-eloquently located diffuse LGGs as a way of preserving function.

The Value of Pre- and Intraoperative Adjuncts on the Extent of Resection of Hemispheric Low-Grade Gliomas: A Retrospective Analysis

BACKGROUND

To achieve maximal resection with minimal risk of postoperative neurologic morbidity, different neurosurgical adjuncts are being used during low-grade glioma (LGG) surgery.

OBJECTIVES

To investigate the effect of pre- and intraoperative adjuncts on the extent of resection (EOR) of hemispheric LGGs.

METHODS

Medical records were reviewed to identify patients of any sex, ≥ 18 years of age, who underwent LGG surgery at X Hospital between January 2005 and July 2013. Patients were divided into eight subgroups based on the use of various combinations of a neuronavigation system alone (NN), functional MRI-diffusion tensor imaging (fMRI-DTI) guided neuronavigation (FD), intraoperative MRI (MR), and direct electrical stimulation (DES). Initial and residual tumors were measured, and mean EOR was compared between groups.

RESULTS

Of all 128 patients, gross total resection was achieved in 23.4%. Overall mean EOR was 81.3% ± 20.5%. Using DES in combination with fMRI-DTI (mean EOR: 86.7% ± 12.4%) on eloquent tumors improved mean EOR significantly after adjustment for potential confounders when compared with NN alone (mean EOR: 76.4% ± 25.5%; p = 0.001).

CONCLUSIONS

Using DES in combination with fMRI and DTI significantly improves EOR when LGGs are located in eloquent areas compared with craniotomies in which only NN was used.

Recent Molecular Advances in Our Understanding of Glioma

Our molecular understanding of glioma has undergone a sea change over the last decade. In this review, we discuss two recent articles that employed whole genome sequencing to subclassify gliomas vis-à-vis known molecular alterations. We further discuss the relevance of these findings vis-à-vis current treatment paradigms.

Outcomes in Reoperated Low-Grade Gliomas

BACKGROUND:

Low-grade gliomas (LGGs) comprise a diverse set of intrinsic brain tumors that correlate strongly with survival. Data on the effect of reoperation are sparse.

OBJECTIVE:

To evaluate the effect of reoperation on patients with LGG.

METHODS:

Fifty-two consecutive patients with reoperated LGGs treated at the University of Washington between 1986 and 2004 were identified and evaluated in a retrospective analysis.

RESULTS:

The average overall survival (OS) for this cohort was 12.95 ± 0.96 years. The overall 10-year survival rate was 57%. The absence of any residual tumor at either the first or second operation was associated with significantly increased OS. Negative prognostic variables for OS included the use of upfront radiation and pathology at recurrence. The average overall progression-free survival to the first recurrence (PFS1) was 6.23 ± 0.51 years. Positive prognostic factors for improved PFS1 included the use of upfront radiation therapy. Variables not associated with differences in PFS1 included the use of upfront chemotherapy, enhancement, pathology, extent of resection, the presence of residual tumor, and Karnofsky Performance Scale score &lt;80. The average overall progression-free survival to the second recurrence was 2.73 ± 0.39 years. Pathology at recurrence was associated with significant differences in progression-free survival to the second recurrence, as was extent of resection at time of first recurrence, and Karnofsky Performance Scale score &lt;80.

CONCLUSION:

This is among the largest studies to assess variables associated with outcome in patients with reoperated LGG. Reresection appears to provide significant benefit, and extent of resection remains the strongest predictor of OS.

IDH mutation status and role of WHO grade and mitotic index in overall survival in grade II-III diffuse gliomas

Diffuse gliomas are up till now graded based upon morphology. Recent findings indicate that isocitrate dehydrogenase (IDH) mutation status defines biologically distinct groups of tumors. The role of tumor grade and mitotic index in patient outcome has not been evaluated following stratification by IDH mutation status. To address this, we interrogated 558 WHO grade II-III diffuse gliomas for IDH1/2 mutations and investigated the prognostic impact of WHO grade within IDH-mutant and IDH-wild type tumor subsets independently. The prognostic impact of grade was modest in IDH-mutant [hazard ratio (HR) = 1.21, 95 % confidence interval (CI) = 0.91-1.61] compared to IDH-wild type tumors (HR = 1.74, 95 % CI = 0.95-3.16). Using a dichotomized mitotic index cut-off of 4/1000 tumor cells, we found that while mitotic index was significantly associated with outcome in IDH-wild type tumors (log-rank p < 0.0001, HR = 4.41, 95 % CI = 2.55-7.63), it was not associated with outcome in IDH-mutant tumors (log-rank p = 0.5157, HR = 1.10, 95 % CI = 0.80-1.51), and could demonstrate a statistical interaction (p < 0.0001) between IDH mutation and mitotic index (i.e., suggesting that the effect of mitotic index on patient outcome is dependent on IDH mutation status). Patient age, an established prognostic factor in diffuse glioma, was significantly associated with outcome only in the IDH-wild type subset, and consistent with prior data, 1p/19q co-deletion conferred improved outcome in the IDH-mutant cohort. These findings suggest that stratification of grade II-III gliomas into subsets defined by the presence or absence of IDH mutation leads to subgroups with distinct prognostic characteristics. Further evaluation of grading criteria and prognostic markers is warranted within IDH-mutant versus IDH-wild type diffuse grade II-III gliomas as independent entities.

Phase 2 study of temozolomide-based chemoradiation therapy for high-risk low-grade gliomas: preliminary results of Radiation Therapy Oncology Group 0424

PURPOSE

Radiation Therapy Oncology Group (RTOG) 0424 was a phase 2 study of a high-risk low-grade glioma (LGG) population who were treated with temozolomide (TMZ) and radiation therapy (RT), and outcomes were compared to those of historical controls. This study was designed to detect a 43% increase in median survival time (MST) from 40.5 to 57.9 months and a 20% improvement in 3-year overall survival (OS) rate from 54% to 65% at a 10% significance level (1-sided) and 96% power.

METHODS AND MATERIALS

Patients with LGGs with 3 or more risk factors for recurrence (age ≥40 years, astrocytoma histology, bihemispherical tumor, preoperative tumor diameter of ≥6 cm, or a preoperative neurological function status of >1) were treated with RT (54 Gy in 30 fractions) and concurrent and adjuvant TMZ.

RESULTS

From 2005 to 2009, 129 evaluable patients (75 males and 54 females) were accrued. Median age was 49 years; 91% had a Zubrod score of 0 or 1; and 69%, 25%, and 6% of patients had 3, 4, and 5 risk factors, respectively. Patients had median and minimum follow-up examinations of 4.1 years and 3 years, respectively. The 3-year OS rate was 73.1% (95% confidence interval: 65.3%-80.8%), which was significantly improved compared to that of prespecified historical control values (P<.001). Median survival time has not yet been reached. Three-year progression-free survival was 59.2%. Grades 3 and 4 adverse events occurred in 43% and 10% of patients, respectively. One patient died of herpes encephalitis.

CONCLUSIONS

The 3-year OS rate of 73.1% for RTOG 0424 high-risk LGG patients is higher than that reported for historical controls (P<.001) and the study-hypothesized rate of 65%.

Advances in the Surgical Management of Low-Grade Glioma

Over the past 2 decades, extent of resection has emerged as a significant prognostic factor in patients with low-grade gliomas (LGGs). Greater extent of resection has been shown to improve overall survival, progression-free survival, and time to malignant transformation. The operative goal in most LGG cases is to maximize extent of resection, while avoiding postoperative neurologic deficits. Several advanced surgical techniques have been developed in an attempt to better achieve maximal safe resection. Intraoperative magnetic resonance imaging, fluorescence-guided surgery, intraoperative functional pathway mapping, and neuronavigation are some of the most commonly used techniques with multiple studies to support their efficacy in glioma surgery. By using these techniques either alone or in combination, patients harboring LGGs have a better prognosis with less surgical morbidity following tumor resection.

Imaging growth and isocitrate dehydrogenase 1 mutation are independent predictors for diffuse low-grade gliomas

BACKGROUND

We explored whether spontaneous imaging tumor growth (estimated by the velocity of diametric expansion) and isocitrate dehydrogenase 1 (IDH1) mutation (estimated by IDH1 immunoexpression) were independent predictors of long-term outcomes of diffuse low-grade gliomas in adults.

METHODS

One hundred thirty-one adult patients with newly diagnosed supratentorial diffuse low-grade gliomas were retrospectively studied.

RESULTS

Isocitrate dehydrogenase 1 mutations were present in 107 patients. The mean spontaneous velocity of diametric expansion was 5.40 ± 5.46 mm/y. During follow-up (mean, 70 ± 54.7 mo), 56 patients presented a malignant transformation and 23 died. The median malignant progression-free survival and the overall survival were significantly longer in cases of slow velocity of diametric expansion (149 and 198 mo, respectively) than in cases of fast velocity of diametric expansion (46 and 82 mo; P < .001 and P < .001, respectively) and in cases with IDH1 mutation (100 and 198 mo, respectively) than in cases without IDH1 mutation (72 mo and not reached; P = .028 and P = .001, respectively). In multivariate analyses, spontaneous velocity of diametric expansion and IDH1 mutation were independent prognostic factors for malignant progression-free survival (P < .001; hazard ratio, 4.23; 95% CI, 1.81-9.40 and P = .019; hazard ratio, 2.39; 95% CI, 1.19-4.66, respectively) and for overall survival (P < .001; hazard ratio, 26.3; 95% CI, 5.42-185.2 and P = .007; hazard ratio, 17.89; 95% CI, 2.15-200.1, respectively).

CONCLUSIONS

The spontaneous velocity of diametric expansion and IDH1 mutation status are 2 independent prognostic values that should be obtained at the beginning of the management of diffuse low-grade gliomas in adults.

The impact of extent of resection on malignant transformation of pure oligodendrogliomas

Object

Recent evidence suggests that a greater extent of resection (EOR) extends malignant progression-free survival among patients with low-grade gliomas (LGGs). These studies, however, rely on the combined analysis of oligodendrogliomas, astrocytomas, and mixed oligoastrocytomas—3 histological subtypes with distinct genetic and molecular compositions. To assess the value of EOR in a homogeneous LGG patient population and delineate its impact on LGG transformation, the authors examined its effect on newly diagnosed supratentorial oligodendrogliomas.

Methods

The authors identified 93 newly diagnosed adult patients with WHO Grade II oligodendrogliomas treated with microsurgical resection at Barrow Neurological Institute. Clinical, laboratory, and radiographic data were collected retrospectively, including 1p/19q codeletion status and volumetric analysis based on T2-weighted MRI.

Results

The median preoperative and postoperative tumor volumes and EOR were 29.0 cm3 (range 1.3–222.7 cm3), 5.2 cm3 (range 0–156.1 cm3), and 85% (range 6%–100%), respectively. Median follow-up was 75.4 months, and there were 14 deaths (15%). Progression and malignant progression were identified in 31 (33%) and 20 (22%) cases, respectively. A greater EOR was associated with longer overall survival (p = 0.005) and progression-free survival (p = 0.004); however, a greater EOR did not prolong the interval to malignant progression, even when controlling for 1p/19q codeletion.

Conclusions

A greater EOR is associated with an improved survival profile for patients with WHO Grade II oligodendrogliomas. However, for this particular LGG patient population, the interval to tumor transformation is not influenced by cytoreduction. These data raise the possibility that the capacity for microsurgical resection to modulate malignant progression is mediated through biological mechanisms specific to nonoligodendroglioma LGG histologies.

Role of radiotherapy in the treatment of gliomas

Malignant gliomas are challenging tumors that are often treated with a multimodality approach. This article focuses on the role of radiotherapy in the management of these tumors. The role of radiotherapy in low-grade gliomas remains controversial and this review focuses on the importance of prognostic factors, recent randomized trials involving radiotherapy, and toxicity from radiotherapy. In terms of high-grade gliomas, radiotherapy has a more established role and this review will address methods that have been evaluated in order to improve radiotherapy outcome. Improvements in radiotherapy delivery, tumor imaging and biologic modifiers may ultimately lead to improved outcome in the treatment of these difficult tumors.

Dynamic 18F-FET PET in newly diagnosed astrocytic low-grade glioma identifies high-risk patients

Because the clinical course of low-grade gliomas in the individual adult patient varies considerably and is unpredictable, we investigated the prognostic value of dynamic (18)F-fluorethyltyrosine ((18)F-FET) PET in the early diagnosis of astrocytic low-grade glioma (World Health Organization grade II).

METHODS

Fifty-nine patients with newly diagnosed low-grade glioma and dynamic (18)F-FET PET before histopathologic assessment were retrospectively investigated. (18)F-FET PET analysis comprised a qualitative visual classification of lesions; assessment of the semiquantitative parameters maximal, mean, and total standardized uptake value as ratio to background and biologic tumor volume; and dynamic analysis of intratumoral (18)F-FET uptake over time (increasing vs. decreasing time-activity curves). The correlation between PET parameters and progression-free survival, overall survival, and time to malignant transformation was investigated.

RESULTS

(18)F-FET uptake greater than the background level was found in 34 of 59 tumors. Dynamic (18)F-FET uptake analysis was available for 30 of these 34 patients. Increasing and decreasing time-activity curves were found in 18 and 12 patients, respectively. Neither the qualitative factor presence or absence of (18)F-FET uptake nor any of the semiquantitative uptake parameters significantly influenced clinical outcome. In contrast, decreasing time-activity curves in the kinetic analysis were highly prognostic for shorter progression-free survival and time to malignant transformation (P < 0.001).

CONCLUSION

Absence of (18)F-FET uptake in newly diagnosed astrocytic low-grade glioma does not generally indicate an indolent disease course. Among the (18)F-FET-positive gliomas, decreasing time-activity curves in dynamic (18)F-FET PET constitute an unfavorable prognostic factor in astrocytic low-grade glioma and, by identifying high-risk patients, may ease treatment decisions.

Radiotherapy in low-grade glioma adult patients: a retrospective survival and neurocognitive toxicity analysis

PURPOSE

The treatment of low-grade glioma is still debated. Surgery is the first-line approach, and the correct timing of radiation therapy has not yet been defined since "early" radiation therapy improves relapse-free survival but not overall survival. Since a longer progression-free survival is desirable, the main issue related to radiotherapy is the incidence of late neurocognitive toxicity.

MATERIALS AND METHODS

Ninety-five patients with low-grade glioma were consecutively treated with early (within 3 months) or late (at disease progression) post-surgical radiation therapy. Clinical and therapeutic factors were entered into the analysis overall (OS) and progression-free (PFS) survival, and the distribution in two accrual periods identified based on the evolution of imaging procedures and radiotherapy techniques were compared. For 6/18 long survivors (LS) without evidence of disease, neurocognitive evaluation was obtained and the dose to the hippocampus region was retrospectively calculated.

RESULTS

Univariate analysis of OS showed a statistically significant advantage for grade 1 and oligodendroglioma histology, better performance status [Karnofsky index (KI)], age <40 years, radical surgery, no steroid treatment; PFS was significantly related with younger age, better KI and "early" radiotherapy. Multivariate analysis of OS confirmed the significance of all variables except surgery; for PFS, only "early" radiotherapy and better KI retained significance. Memory impairment was evident in 4/6 of the LS tested; quality of life was good and executive functions were normal.

CONCLUSION

Radiotherapy remains an essential component in the treatment of low-grade glioma. Prospective studies are needed to evaluate the relative contributions of the disease itself and of surgery, radiation and chemotherapy to long-term neurocognitive damage.

Quantitative MR perfusion parameters related to survival time in high-grade gliomas

OBJECTIVES

To evaluate the quantitative parameters obtained from dynamic MR T2*-weighted images as predictors of survival taking into consideration the biasing effects of other survival-related covariates.

METHODS

Thirty-nine patients (60 ± 14 years; survival 267 ± 191 days) with high-grade gliomas (8 grade III, 31 grade IV) were retrospectively included in the study. Additional data incorporated Karnofsky performance scale, tumour resection extension after surgery and type of treatment. Dynamic T2*-weighted MRI was acquired before treatment. Tumour curves were extracted for each voxel, and several quantitative parameters were obtained from the whole tumour volume and the 10 % maximum values. Additional image covariates included the presence of necrosis, single or multiple lesions, and tumour and oedema volumes. The relationship between quantitative parameters and survival was assessed using clusterisation techniques and the log-rank method. Cox regression analysis was used to evaluate each parameter's predictive value.

RESULTS

Only the mean of the 10 % maximum values of the transfer coefficient showed an independent relationship with patient survival (log-rank chi-squared test <0.001, Cox regression P = 0.015), with higher values corresponding to lower survival rates.

CONCLUSIONS

High maximum transfer coefficient values show an independent statistical relationship with low survival in high-grade glioma patients. This imaging biomarker can be used as a predictor of prognosis.

Spontaneous and therapeutic prognostic factors in adult hemispheric World Health Organization Grade II gliomas: a series of 1097 cases

Object

The spontaneous prognostic factors and optimal therapeutic strategy for WHO Grade II gliomas (GIIGs) have yet to be unanimously defined. Specifically, the role of resection is still debated, most notably because the actual amount of resection has seldom been assessed.

Methods

Cases of GIIGs treated before December 2007 were extracted from a multicenter database retrospectively collected since January 1985 and prospectively collected since 1996. Inclusion criteria were a patient age ≥ 18 years at diagnosis, histological diagnosis of WHO GIIG, and MRI evaluation of tumor volume at diagnosis and after initial surgery. One thousand ninety-seven lesions were included in the analysis. The mean follow-up was 7.4 years since radiological diagnosis. Factors significant in a univariate analysis (with a p value ≤ 0.1) were included in the multivariate Cox proportional hazard regression model analysis.

Results

At the time of radiological diagnosis, independent spontaneous factors of a poor prognosis were an age ≥ 55 years, an impaired functional status, a tumor location in a nonfrontal area, and, most of all, a larger tumor size. When the study starting point was set at the time of first treatment, independent favorable prognostic factors were limited to a smaller tumor size, an epileptic symptomatology, and a greater extent of resection.

Conclusions

This large series with its volumetric assessment refines the prognostic value of previously stressed clinical and radiological parameters and highlights the importance of tumor size and location. The results support additional arguments in favor of the predominant role of resection, in accordance with recently reported experiences.

Low-grade glioma surgery in eloquent areas: volumetric analysis of extent of resection and its impact on overall survival. A single-institution experience in 190 patients

Object

A growing number of published studies have recently demonstrated the role of resection in overall survival (OS) for patients with gliomas. In this retrospective study, the authors objectively investigated the role of the extent of resection (EOR) in OS in patients with low-grade gliomas (LGGs).

Methods

Between 1998 and 2011, 190 patients underwent surgery for LGGs. All surgical procedures were conducted under corticosubcortical stimulation. The EOR was established by analyzing the pre- and postoperative volumes of the gliomas on T2-weighted MRI studies. The difference between the preoperative tumor volumes was also investigated by measuring the volumetric difference between the T2- and T1-weighted MRI images (ΔVT2T1) to evaluate how the diffusive tumor-growing pattern affected the EOR achieved.

Results

The median preoperative tumor volume was 55 cm3, and in almost half of the patients the EOR was greater than 90%. In this study, patients with an EOR of 90% or greater had an estimated 5-year OS rate of 93%, those with EOR between 70% and 89% had a 5-year OS rate of 84%, and those with EOR less than 70% had a 5-year OS rate of 41% (p < 0.001). New postoperative deficits were noted in 43.7% of cases, while permanent deficits occurred in 3.16% of cases. There were 41 deaths (21.6%), and the median follow-up was 4.7 years.

A further volumetric analysis was also conducted to compare 2 different intraoperative protocols (Series 1 [intraoperative electrical stimulation alone] vs Series 2 [intraoperative stimulation plus overlap of functional MRI/fiber tracking diffusion tensor imaging data on a neuronavigation system]). Patients in Series 1 had a median EOR of 77%, while those in Series 2 had a median EOR of 90% (p = 0.0001). Multivariate analysis showed that OS is influenced not only by EOR (p = 0.001) but also by age (p = 0.003), histological subtype (p = 0.005), and the ΔVT2T1 value (p < 0.0001). Progression-free survival is similarly influenced by histological subtype (fibrillary astrocytoma, p = 0.003), EOR (p < 0.0001), and ΔVT2T1 value (p < 0.0001), as is malignant progression–free survival (p = 0.003, p < 0.0001, and p < 0.0001, respectively). Finally, the study shows that the higher the ΔVT2T1 value, the less extensive the currently possible resection, highlighting an apparent correlation between the ΔVT2T1 value itself and EOR (p < 0.0001).

Conclusions

The EOR and the ΔVT2T1 values are the strongest independent predictors in improving OS as well as in delaying tumor progression and malignant transformation. Furthermore, the ΔVT2T1 value may be useful as a predictive index for EOR. Finally, due to intraoperative corticosubcortical mapping and the overlap of functional data on the neuronavigation system, major resection is possible with an acceptable risk and a significant increase in expected OS.

IDH1/2 mutation is a prognostic marker for survival and predicts response to chemotherapy for grade II gliomas concomitantly treated with radiation therapy

Reliable prognostic biomarkers of grade II gliomas remain unclear. This study aimed to examine the role of mutations of isocitrate dehydrogenase (IDH1/2), 1p/19q co-deletion, and clinicopathological factors in patients with grade II glioma who were primarily treated with radiotherapy or chemoradiotherapy after surgery. Seventy-two consecutive patients, including 49 cases of diffuse astrocytomas (DA), 4 oligodendrogliomas (OL) and 19 oligoastrocytomas (OA), who underwent treatment from 1991 to 2010 at a single institution were examined. The overall survival (OS) of the DA patients (8.3 years) was significantly shorter than that of the OL and OA patients (11.7 years). IDH1/2 mutations were found in 46.9% of the DA patients and 82.6% of the OL and OA patients. The progression-free survival (PFS) and OS of the patients with IDH1/2 mutations (8.4 and 16.3 years) were significantly longer than those of the patients without IDH1/2 mutations (3.3 and 4.5 years). Among the patients with IDH1/2 mutations, those who were initially treated with chemoradiotherapy including nimustine hydrochloride (ACNU), had significantly longer PFS than those treated with radiotherapy alone, whereas no significant difference in PFS was observed between the chemoradiotherapy and radiotherapy groups in the patients without IDH1/2 mutations. Oligodendroglial tumors, age <40 years, initial Karnofsky performance status (KPS) ≥80, and IDH1/2 mutations were favorable prognostic factors regarding PFS and OS. IDH1/2 mutation was a predictive factor of response to chemoradiotherapy in grade II gliomas. Patients with IDH1/2 mutations may benefit more from chemoraiotherapy than those without IDH1/2 mutations.

Spatial characteristics of newly diagnosed grade 3 glioma assessed by magnetic resonance metabolic and diffusion tensor imaging

The spatial heterogeneity in magnetic resonance (MR) metabolic and diffusion parameters and their relationship were studied for patients with treatment-naive grade 3 gliomas. MR data were evaluated from 51 patients with newly diagnosed grade 3 gliomas. Anatomic, diffusion, and metabolic imaging data were considered. Variations in metabolite levels, apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were evaluated in regions of gadolinium enhancement and T2 hyperintensity as well as regions with abnormal metabolic signatures. Contrast enhancement was present in only 21 of the 51 patients. When present, the enhancing component of the lesion had higher choline-to-N-acetylaspartate index (CNI), higher choline, lower N-acetylaspartate, similar creatine, similar ADC and FA, and higher lactate/lipid than the nonenhancing lesion. Regions with CNI ≥ 4 had higher choline, lower N-acetylaspartate, higher lactate/lipid, higher ADC, and lower FA than normal-appearing white matter and regions with intermediate CNI values. For lesions that exhibited gadolinium enhancement, the metabolite levels and diffusion parameters in the region of enhancement were consistent with it corresponding to the most abnormal portion of the tumor. For nonenhancing lesions, areas with CNI ≥ 4 were the most abnormal in metabolic and diffusion parameters. This suggests that the region with the highest CNI might provide a good target for biopsies for nonenhancing lesions to obtain a representative histologic diagnosis of its degree of malignancy. Metabolic and diffusion parameter levels may be of interest not only for directing tissue sampling but also for defining the targets for focal therapy and assessing response to therapy.

IDH1/2 mutations in WHO grade II astrocytomas associated with localization and seizure as the initial symptom

INTRODUCTION

Seizures are the most common initial symptom in patients with low-grade glioma and their occurrence strongly depends on the tumor location. The majority of low-grade gliomas reveal mutations in the genes encoding isocitrate-dehydrogenase 1 (IDH1) or 2 (IDH2). These mutations are associated with metabolic changes that are potentially epileptogenic. We investigated the correlation between IDH1/2 mutations and tumor localization and seizure as the initial symptom.

MATERIALS AND METHODS

This retrospective study included patients with a diagnosis of WHO grade II astrocytoma and cortical infiltration and in whom initial symptoms were documented and biopsy tissue was available for IDH1/2 analysis. IDH1/2 mutation analysis was performed by direct sequencing or by immunohistochemistry with an antibody which detects mutated protein IDH1 R132H. Sequencing was carried out if immunohistochemistry was negative. IDH1/2 status was defined as mutated if either of these investigations were positive.

RESULTS

Seventy-nine patients were included. IDH1 or IDH2 mutation was present in 63 (80%) patients who on average were younger than patients without IDH1/2 mutation (40 vs. 47 years, p=0.0331, t-test). IDH1/2 mutations were associated with frontal tumor location (p=0.0202). All 12 tumors in the insula revealed IDH1/2 mutations. Seizure as the initial symptom was recorded in 57 (72%) patients and was associated with IDH1 or IDH2 mutation by multivariate analysis (OR 22.563, p=0.0019).

CONCLUSION

In WHO grade II astrocytomas, IDH1/2 mutations mostly occur in tumors infiltrating the frontal lobe. Seizure as the initial symptom is associated with IDH1 or IDH2 mutation.

Low-grade gliomas in adults

In recent years, advances in the understanding of low-grade glioma (LGG) biology have driven new paradigms in molecular markers, diagnostic imaging, operative techniques and technologies, and adjuvant therapies. Taken together, these developments are collectively pushing the envelope toward improved quality of life and survival. In this article, the authors evaluate the recent literature to synthesize a comprehensive review of LGGs in the modern neurosurgical era.

Extent of resection influences outcomes for patients with gliomas

In recent years, advances in our understanding of the biology of low-grade gliomas (LGG) and high-grade gliomas (HGG) have driven new paradigms in molecular markers, diagnostic imaging, operative techniques and technologies, and adjuvant therapies. Taken together, these developments are collectively pushing the envelope towards improved quality of life and survival. Here, we review the recent literature to synthesize a comprehensive review of the value of extent of resection for LGGs and HGGs in the modern neurosurgical era.

Low-grade gliomas in adults

In recent years, advances in the understanding of low-grade glioma (LGG) biology have driven new paradigms in molecular markers, diagnostic imaging, operative techniques and technologies, and adjuvant therapies. Taken together, these developments are collectively pushing the envelope toward improved quality of life and survival. In this article, the authors evaluate the recent literature to synthesize a comprehensive review of LGGs in the modern neurosurgical era.