Phase II study of first-line chemotherapy with temozolomide in recurrent oligodendroglial tumors: the European Organization for Research and Treatment of Cancer Brain Tumor Group Study 26971

Trends in the Management of Oligodendrogliomas: A Multinational and Multidisciplinary Survey Study

OBJECTIVE

Oligodendrogliomas present challenges in management despite their favorable prognosis. Optimal therapeutic strategies are not well-established. We aimed to characterize current practice patterns and identify areas of discordance in oligodendroglioma management.

METHODS

A 20-question survey was distributed February-July 2023 to 4 professional neurosurgery/neuro-oncology societies to assess practices in oligodendroglioma management. The survey collected data on demographics, diagnostic practices, and treatment decisions. Data analysis was performed using chi-square/Fisher's exact tests.

RESULTS

Sixty-three physicians responded, representing 12 countries. Diagnostic practices were consistent among respondents. However, variations in management recommendations were observed. Providers were divided between rarely (36.5%), sometimes (25.4%), and often (30.2%) using temozolomide (TMZ) as sole chemotherapy for patients with newly diagnosed oligodendroglioma. For patients with subtotal resection of grade 2 oligodendroglioma, 33.3% of providers recommended upfront radiation/chemotherapy, 27.0% recommended observation, and the remaining 39.7% were divided among options including surgery, chemotherapy, and clinical trials. European providers more frequently recommended surgery (33.3% vs. 0.0%), whereas radiation/chemotherapy (35.7% vs. 26.7%) or observation (31.0% vs. 13.3%) was more commonly recommended by U.S./Canada providers (P = 0.009). Providers also disagreed on adjuvant therapy for grade 3 oligodendroglioma. 47.6% recommended radiation/procarbazine, lomustine, and vincristine, and 33.3% recommended radiation/TMZ. This decision varied by region, with European providers more frequently recommending radiation/procarbazine, lomustine, and vincristine (86.7% vs. 33.3%) and U.S./Canadian providers more frequently recommending radiation/TMZ (40.5% vs. 6.7%; P = 0.004).

CONCLUSIONS

This study underscores the complexity of oligodendroglioma management and the importance of ongoing research to refine therapeutic strategies. Further studies, especially with the introduction of isocitrate dehydrogenase inhibitors in practice, are warranted to track practice patterns and reassess recommendations.

Survival Outcomes Associated With First-Line Procarbazine, CCNU, and Vincristine or Temozolomide in Combination With Radiotherapy in IDH-Mutant 1p/19q-Codeleted Grade 3 Oligodendroglioma

PURPOSE

Patients with IDH-mutant 1p/19q-codeleted grade 3 oligodendroglioma (O3IDHmt/Codel) benefit from adding alkylating agent chemotherapy to radiotherapy (RT). However, the optimal chemotherapy regimen between procarbazine, 1-(2-Chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), and vincristine (PCV) and temozolomide (TMZ) remains unclear given the lack of randomized trial data comparing both regimens.

METHODS

The objective was to assess the overall survival (OS) and progression-free survival (PFS) associated with first-line PCV/RT versus TMZ/RT in patients newly diagnosed with O3IDHmt/Codel. We included patients with histologically proven O3IDHmt/Codel (according to WHO criteria) from the French national prospective cohort Prise en charge des OLigodendrogliomes Anaplasiques (POLA). All tumors underwent central pathologic review. OS and PFS from surgery were estimated using the Kaplan-Meier method and Cox regression model.

RESULTS

305 newly diagnosed patients with O3IDHmt/Codel treated with RT and chemotherapy between 2008 and 2022 were included, of which 67.9% of patients (n = 207) were treated with PCV/RT and 32.1% with TMZ/RT (n = 98). The median follow-up was 78.4 months (IQR, 44.3-102.7). The median OS was not reached (95% CI, Not reached [NR] to NR) in the PCV/RT group and was 140 months (95% CI, 110 to NR) in the TMZ/RT group (log-rank P = .0033). On univariable analysis, there was a significant difference in favor of PCV/RT in both 5-year (PCV/RT: 89%, 95% CI, 85 to 94; TMZ/RT: 75%, 95% CI, 66 to 84) and 10-year OS (PCV/RT: 72%, 95% CI, 61 to 85; TMZ/RT: 60%, 95% CI, 49 to 73), which was confirmed using the multivariable Cox model adjusted for age, type of surgery, gender, Eastern Cooperative Oncology Group performance status, and CDKN2A homozygous deletion (hazard ratio, 0.53 for PCV/RT, 95% CI, 0.30 to 0.92, P = .025).

CONCLUSION

In patients with newly diagnosed O3IDHmt/Codel from the POLA cohort, first-line PCV/RT was associated with better OS outcomes compared with TMZ/RT. Our data suggest that the improved safety profile associated with TMZ comes at the cost of inferior efficacy in this population. Further investigation using prospective randomized studies is warranted.

Non-coding RNAs (ncRNAs) as therapeutic targets and biomarkers in oligodendroglioma

Oligodendrogliomas (ODGs) are neuroepithelial tumors that need personalized treatment plans because of their unique molecular and histological features. Non-coding RNAs form an epigenetic class of molecules that act as the first steps in gene regulation. They consist of microRNAs, long non-coding RNAs, and circular RNAs. These molecules significantly participate in ODG pathogenesis by regulating ODG initiation, progression, and treatment response. This review is designated to analyze the literature and describe the genomic profile of ODGs, the complex actions of ncRNAs in ODGs pathogenesis and treatment, and their roles as appropriate biomarkers and as one of the precision mechanisms action targets, such as antisense oligonucleotides, small interfering RNAs, gene therapy vectors, peptide nucleic acids, and small molecule inhibitors. Overall, ncRNAs considerably alter the pathological spectrum of ODGs by influencing fundamental processes in tumor biology. Applying ncRNAs in a clinical context exhibits promise for enhanced diagnosis and individualized therapeutic interventions. Nevertheless, the delivery efficacy and potential adverse "off-target" sequels retain the main obstacles undermining clinical potential. Continuous research and technological advancements in ncRNAs offer new insights and promising prospects for revolutionizing oligodendroglioma care, leading to better, personalized treatment outcomes.

Construction and Validation of Nomograms for Predicting Overall Survival and Cancer-Specific Survival in Patients with Primary Anaplastic Oligodendroglioma

OBJECTIVE

Anaplastic oligodendroglioma (AOD) is a rare high-grade central nervous system tumor. The current research on prognostic prediction of AOD remains limited. This study aimed to identify prognostic factors and establish the nomograms to predict overall survival (OS) and cancer-specific survival (CSS) for patients with AOD.

METHODS

Patients diagnosed with AOD between 1992 and 2020 were extracted from the Surveillance, Epidemiology, and End Result database. We performed univariate and multivariate Cox regression analyses to identify independent prognostic factors based on the training group. Kaplan-Meier survival curves were used to compare the impact of various independent factors on patient prognosis. For OS and CSS, the nomograms were constructed and verified by the validation group. Harrell''s concordance index, receiver operating characteristic curves, calibration curves, and decision curve analyses were used to assess the discrimination, consistency, and clinical value of the nomograms.

RESULTS

A total of 1202 AOD patients were enrolled, being randomly divided into training (n = 841) and validation (n = 361) groups (7:3 ratio). Univariate and multivariate Cox analysis identified 4 significant independent factors (tumor site, age, surgery, and chemotherapy). For OS and CSS, Harrell''s concordance index were 0.731 (0.705-0.757) and 0.728 (0.701-0.754) in the training group, 0.688 (0.646-0.731) and 0.684 (0.639-0.729) in the validation group, respectively. Receiver operating characteristic curves and Calibration curves showed good discrimination and consistency, respectively. In addition, the decision curve analyses curves showed the nomograms have good clinical benefits.

CONCLUSIONS

We successfully established the nomograms to predict the OS and CSS for AOD patients. The nomograms showed good performance in prognostic prediction, assisting clinicians in evaluating patient prognosis and personalizing treatment plans.

Global and Gender Equity in Oligodendroglioma Research: A Comprehensive Bibliometric Analysis Following the COVID-19 Pandemic

Oligodendrogliomas are rare brain tumors arising from oligodendrocytes; there is a limited understanding of their pathogenesis, which leads to challenges in diagnosis, prognosis, and treatment. This study aimed to conduct a comprehensive bibliometric analysis of the oligodendroglioma literature to assess the current state of research, identify research trends, and elucidate implications for future research. The Lens® database was used to retrieve journal articles related to "oligodendroglioma" without geographic or temporal restrictions. Year-on-year trends in publication and funding were analyzed. Global and gender equity were assessed using the Namsor® Application programming interface. Collaboration patterns were explored using network visualizations. Keyword analysis revealed the most prominent themes in oligodendroglioma research. Out of 9701 articles initially retrieved, 8381 scholarly journal articles were included in the final analysis. Publication trends showed a consistent increase until 2020, followed by a sharp decline likely due to the COVID-19 pandemic. Global representation revealed researchers from 86 countries, with limited participation from low and middle-income countries (LMICs). Gender inequity was evident, with 78.7% of researchers being male. Collaboration analysis revealed a highly interconnected research community. Prognosis, genetic aberrations (particularly "IDH" mutations), and therapeutic options (including chemotherapy and radiotherapy) emerged as dominant research themes. The COVID-19 pandemic impacted oligodendroglioma research funding and publication trends, highlighting the importance of robust funding mechanisms. Global and gender inequities in research participation underscore the need for fostering inclusive collaboration, especially in LMICs. The interconnected research community presents opportunities for knowledge exchange and innovation. Keyword analysis highlights current research trends and a shift to genetic and molecular understanding.

Prediction of Tumor Development and Urine-Based Liquid Biopsy for Molecule-Targeted Therapy of Gliomas

The timing of the acquisition of tumor-specific gene mutations and the systems by which these gene mutations are acquired during tumorigenesis were clarified. Advances in our understanding of tumorigenesis are being made every day, and therapies targeting fundamental genetic alterations have great potential for cancer treatment. Moreover, our research team successfully estimated tumor progression using mathematical modeling and attempted early diagnosis of brain tumors. We developed a nanodevice that enables urinary genetic diagnosis in a simple and noninvasive manner. Mainly on the basis of our research and experience, this review article presents novel therapies being developed for central nervous system cancers and six molecules, which upon mutation cause tumorigenesis and tumor progression. Further understanding of the genetic characteristics of brain tumors will lead to the development of precise drugs and improve individual treatment outcomes.

Thirty years of progress in the management of low-grade gliomas

This paper reviews 30 years of developments in the area of low-grade gliomas. This includes the changes in diagnostics with the incorporation of 1p/19q and IDH mutations in the diagnostic classifier, the improved surgical techniques, improved delivery of radiotherapy and chemotherapy. More recently, the better understanding of the altered cellular processes has lead to the development of novel drugs that may alter completely alter the management of patients early in the course of their disease.

Formononetin: A Pathway to Protect Neurons

Formononetin (FMN) is a phytoestrogen member of the flavonoid family, which has the pharmacological effects of antioxidative, antihypertensive, antitumor, and anti-infective. FMN demonstrates potential in the prevention and treatment of diseases, specifically neurological diseases, such as traumatic brain injury (TBI), spinal cord injury (SCI), ischemic stroke, cerebral ischemia-reperfusion, Alzheimer’s disease, and nerve tumor. Herein, a literature search is conducted to provide information on the signaling pathways of neuroprotection of formononetin based on the neuroprotective study. The significant neuroprotective function of FMN makes it a novel candidate for the development of drugs targeting the central nervous system.

Promising Chemotherapy for Malignant Pediatric Brain Tumor in Recent Biological Insights

Brain tumors are the most widespread malignancies in children around the world. Chemotherapy plays a critical role in the treatment of these tumors. Although the current chemotherapy process has a remarkable outcome for a certain subtype of brain tumor, improving patient survival is still a major challenge. Further intensive treatment with conventional non-specific chemotherapy could cause additional adverse reactions without significant advancement in survival. Recently, patient derived brain tumor, xenograft, and whole genome analysis using deep sequencing technology has made a significant contribution to our understanding of cancer treatment. This realization has changed the focus to new agents, targeting the molecular pathways that are critical to tumor survival or proliferation. Thus, many novel drugs targeting epigenetic regulators or tyrosine kinase have been developed. These selective drugs may have less toxicity in normal cells and are expected to be more effective than non-specific chemotherapeutics. This review will summarize the latest novel targets and corresponding candidate drugs, which are promising chemotherapy for brain tumors according to the biological insights.

Oligodendroglioma: A Review of Management and Pathways

Anaplastic oligodendrogliomas are a type of glioma that occurs primarily in adults but are also found in children. These tumors are genetically defined according to the mutations they harbor. Grade II and grade III tumors can be differentiated most of the times by the presence of anaplastic features. The earliest regimen used for the treatment of these tumors was procarbazine, lomustine, and vincristine. The treatment modalities have shifted over time, and recent studies are considering immunotherapy as an option as well. This review assesses the latest management modalities along with the pathways involved in the pathogenesis of this malignancies.

Mathematical Modeling and Mutational Analysis Reveal Optimal Therapy to Prevent Malignant Transformation in Grade II IDH-Mutant Gliomas

Isocitrate dehydrogenase-mutant low-grade gliomas (IDHmut-LGG) grow slowly but frequently undergo malignant transformation, which eventually leads to premature death. Chemotherapy and radiotherapy treatments prolong survival, but can also induce genetic (or epigenetic) alterations involved in transformation. Here, we developed a mathematical model of tumor progression based on serial tumor volume data and treatment history of 276 IDHmut-LGGs classified by chromosome 1p/19q codeletion (IDH^mut/1p19q^codel and IDH^mut/1p19q^noncodel) and performed genome-wide mutational analyses, including targeted sequencing and longitudinal whole-exome sequencing data. These analyses showed that tumor mutational burden correlated positively with malignant transformation rate, and chemotherapy and radiotherapy significantly suppressed tumor growth but increased malignant transformation rate per cell by 1.8 to 2.8 times compared with before treatment. This model revealed that prompt adjuvant chemoradiotherapy prolonged malignant transformation-free survival in small IDHmut-LGGs (≤ 50 cm³). Furthermore, optimal treatment differed according to genetic alterations for large IDHmut-LGGs (> 50 cm³); adjuvant therapies delayed malignant transformation in IDH^mut/1p19q^noncodel but often accelerated it in IDH^mut/1p19q^codel. Notably, PI3K mutation was not associated with malignant transformation but increased net postoperative proliferation rate and decreased malignant transformation-free survival, prompting the need for adjuvant therapy in IDH^mut/1p19q^codel. Overall, this model uncovered therapeutic strategies that could prevent malignant transformation and, consequently, improve overall survival in patients with IDHmut-LGGs. SIGNIFICANCE: A mathematical model successfully estimates malignant transformation-free survival and reveals a link between genetic alterations and progression, identifying precision medicine approaches for optimal treatment of IDH-mutant low-grade gliomas.

Recent developments and future directions in adult lower-grade gliomas: Society for Neuro-Oncology (SNO) and European Association of Neuro-Oncology (EANO) consensus

The finding that most grades II and III gliomas harbor isocitrate dehydrogenase (IDH) mutations conveying a relatively favorable and fairly similar prognosis in both tumor grades highlights that these tumors represent a fundamentally different entity from IDH wild-type gliomas exemplified in most glioblastoma. Herein we review the most recent developments in molecular neuropathology leading to reclassification of these tumors based upon IDH and 1p/19q status, as well as the potential roles of methylation profiling and deletional analysis of cyclin-dependent kinase inhibitor 2A and 2B. We discuss the epidemiology, clinical manifestations, benefit of surgical resection, and neuroimaging features of lower-grade gliomas as they relate to molecular subtype, including advanced imaging techniques such as 2-hydroxyglutarate magnetic resonance spectroscopy and amino acid PET scanning. Recent, ongoing, and planned studies of radiation therapy and both cytotoxic and targeted chemotherapies are summarized, including both small molecule and immunotherapy approaches specifically targeting the mutant IDH protein.

Histopathological grading affects survival in patients with IDH-mutant grade II and grade III diffuse gliomas

BACKGROUND

Diffuse grade II and grade III gliomas are actually classified in accordance with the presence of isocitrate dehydrogenase mutation (IDH-mut) and the deletion of both 1p and 19q chromosome arms (1p/19q codel). The role of tumour grading as independent prognostic factor in these group of tumours remains matter of debate. The aim of this study was to determine if grade is an independent prognostic factor and not somehow associated to IDH mutation and 1p/19q status of the tumour.

METHODS

We analysed 399 consecutive patients with newly diagnosed, histologically proven World Health Organisation (WHO) 2016 grade II or grade III IDH-mut gliomas, assessed by polymerase chain reaction, immunohistochemistry or next-generation sequencing (NGS).

RESULTS

The analysis included 399 patients with grade II (n = 250, 62.7%) or grade III (n = 149, 37.3%) diffuse gliomas. Median follow-up time was 105.3 months. Median survival was 148.1 months. In multivariate analysis, grade II (hazard ratio [HR] = 0.342, 95% confidence interval [CI]: 0.221-0.531; P < 0.001) and 1p/19q codeletion (HR = 0.440, 95% CI: 0.290-0.668; P < 0.001) were independently associated with a lower risk for death. The difference in survival remained significant (p = 0.006 in astrocytomas, p = 0.014 in oligodendrogliomas) when adjusted for histological subtype. Residual disease after surgery (or biopsy) negatively affected survival (HR: 2.151, 95% CI: 1.375-3.367, P = 0.001). Post-surgical treatment with radiotherapy + adjuvant chemotherapy improved survival compared with follow-up and other treatments (HR: 0.316, 95% CI: 0.156-0.641, P = 0.001).

CONCLUSIONS

In our study, histopathological grade still affects survival in IDH-mutant WHO grade II and III diffuse gliomas. This effect appears to be independent from molecular features, extension of surgical resection and post-surgical treatments. Therefore, physicians should continue to take into account tumour grade, along their molecular characteristics, for a better clinical and therapeutic management of the patients.

Thioredoxin, Glutathione and Related Molecules in Tumors of the Nervous System

BACKGROUND

Central Nervous System (CNS) tumors have a poor survival prognosis due to their invasive and heterogeneous nature, in addition to the resistance to multiple treatments.

OBJECTIVE

In this paper, the main aspects of brain tumor biology and pathogenesis are reviewed both for primary tumors of the brain, (i.e., gliomas) and for metastasis from other malignant tumors, namely lung cancer, breast cancer and malignant melanoma which account for a high percentage of overall malignant brain tumors. We review the role of antioxidant systems, namely the thioredoxin and glutathione systems, in the genesis and/or progression of brain tumors.

METHODS

Although overexpression of Thioredoxin Reductase (TrxR) and Thioredoxin (Trx) is often linked to increased malignancy rate of brain tumors, and higher expression of Glutathione (GSH) and Glutathione S-Transferases (GST) are associated to resistance to therapy, several knowledge gaps still exist regarding for example, the role of Peroxiredoxins (Prx), and Glutaredoxins (Grx).

CONCLUSION

Due to their central role in redox homeostasis and ROS scavenging, redox systems are potential targets for new antitumorals and examples of innovative therapeutics aiming at improving success rates in brain tumor treatment are discussed.

Clinical impact of revisions to the WHO classification of diffuse gliomas and associated future problems

The publication of the 2016 World Health Organization Classification of Tumors of the Central Nervous System (2016 WHO CNS) represented a major change in the classification of brain tumors. It is essential to determine the IDH and 1p/19q statuses of diffuse gliomas to ensure that the final diagnosis is accurate. The integrated diagnostic method outlined in the 2016 WHO CNS has enabled more precise prediction of the prognoses of diffuse gliomas. However, there are further two points that need to be addressed when planning future clinical trials. The first is the problems with the WHO grading system for diffuse gliomas. The second is that examinations for IDH mutations and 1p/19q co-deletion are not sufficient on their own to accurately predict the prognosis of diffuse glioma patients. Risk of an IDH-mut diffuse glioma should be evaluated based on a combination of clinical factors (age and the resection rate), molecular factors (the presence/absence of CDKN2A deletion), and histological factors (morphology and the mitotic index). Glioblastoma (GBM) have also been classified according to their IDH status; however, the frequency of IDH gene mutations is only 5-10% in GBM. Other molecular markers such as MGMT methylation, pTERT mutations and EGFR amplification could be more important to predict clinical outcome. Therefore, the next revision of the classification of diffuse gliomas will propose a detailed classification based on additional markers. In the near future, treatments for diffuse gliomas will be chosen according to the molecular profile of each tumor.

Computational Study of Novel Natural Inhibitors Targeting O6-Methylguanine-DNA Methyltransferase

OBJECTIVE

To screen ideal lead compounds from a drug library (ZINC15 database) with potential inhibition effect against O⁶-methylguanine-DNA methyltransferase (MGMT) to contribute to medication design and refinement.

METHODS

A series of computer-aided virtual screening techniques were used to identify potential inhibitors of MGMT. Structure-based virtual screening by LibDock was carried out to calculate LibDock scores, followed by absorption, distribution, metabolism, and excretion and toxicity predictions. Molecule docking was employed to demonstrate binding affinity and mechanism between the selected ligands and MGMT protein. Molecular dynamics simulation was performed to evaluate stability of the ligand-MGMT complex under natural circumstances.

RESULTS

Two novel natural compounds, ZINC000008220033 and ZINC000001529323, from the ZINC15 database were found to bind with MGMT with a higher binding affinity together with more favorable interaction energy. Also, they were predicted to have less rodent carcinogenicity, Ames mutagenicity, and developmental toxicity potential as well as noninhibition with cytochrome P-450 2D6. Molecular dynamics simulation analysis demonstrated that the 2 complexes ZINC000008220033-MGMT and ZINC000001529323-MGMT had more favorable potential energy compared with reference ligand O⁶-benzylguanine, and they could exist stably in the natural environment.

CONCLUSIONS

This study elucidated that ZINC000008220033 and ZINC000001529323 were ideal lead compounds with potential inhibition targeting to MGMT protein. These compounds were selected as safe drug candidates and may contribute a solid basis for MGMT target medication design and improvement.

Focus on Formononetin: Anticancer Potential and Molecular Targets

Formononetin, an isoflavone, is extracted from various medicinal plants and herbs, including the red clover (Trifolium pratense) and Chinese medicinal plant Astragalus membranaceus. Formononetin's antioxidant and neuroprotective effects underscore its therapeutic use against Alzheimer's disease. Formononetin has been under intense investigation for the past decade as strong evidence on promoting apoptosis and against proliferation suggests for its use as an anticancer agent against diverse cancers. These anticancer properties are observed in multiple cancer cell models, including breast, colorectal, and prostate cancer. Formononetin also attenuates metastasis and tumor growth in various in vivo studies. The beneficial effects exuded by formononetin can be attributed to its antiproliferative and cell cycle arrest inducing properties. Formononetin regulates various transcription factors and growth-factor-mediated oncogenic pathways, consequently alleviating the possible causes of chronic inflammation that are linked to cancer survival of neoplastic cells and their resistance against chemotherapy. As such, this review summarizes and critically analyzes current evidence on the potential of formononetin for therapy of various malignancies with special emphasis on molecular targets.

PI3K/AKT/mTOR Pathway Alterations Promote Malignant Progression and Xenograft Formation in Oligodendroglial Tumors

PURPOSE

Oligodendroglioma has a relatively favorable prognosis, however, often undergoes malignant progression. We hypothesized that preclinical models of oligodendroglioma could facilitate identification of therapeutic targets in progressive oligodendroglioma. We established multiple oligodendroglioma xenografts to determine if the PI3K/AKT/mTOR signaling pathway drives tumor progression.

EXPERIMENTAL DESIGN

Two anatomically distinct tumor samples from a patient who developed progressive anaplastic oligodendroglioma (AOD) were collected for orthotopic transplantation in mice. We additionally implanted 13 tumors to investigate the relationship between PI3K/AKT/mTOR pathway alterations and oligodendroglioma xenograft formation. Pharmacologic vulnerabilities were tested in newly developed AOD models in vitro and in vivo.

RESULTS

A specimen from the tumor site that subsequently manifested rapid clinical progression contained a PIK3CA mutation E542K, and yielded propagating xenografts that retained the OD/AOD-defining genomic alterations (IDH1 ^R132H and 1p/19q codeletion) and PIK3CA ^E542K, and displayed characteristic sensitivity to alkylating chemotherapeutic agents. In contrast, a xenograft did not engraft from the region that was clinically stable and had wild-type PIK3CA. In our panel of OD/AOD xenografts, the presence of activating mutations in the PI3K/AKT/mTOR pathway was consistently associated with xenograft establishment (6/6, 100%). OD/AOD that failed to generate xenografts did not have activating PI3K/AKT/mTOR alterations (0/9, P < 0.0001). Importantly, mutant PIK3CA oligodendroglioma xenografts were vulnerable to PI3K/AKT/mTOR pathway inhibitors in vitro and in vivo-evidence that mutant PIK3CA is a tumorigenic driver in oligodendroglioma.

CONCLUSIONS

Activation of the PI3K/AKT/mTOR pathway is an oncogenic driver and is associated with xenograft formation in oligodendrogliomas. These findings have implications for therapeutic targeting of PI3K/AKT/mTOR pathway activation in progressive oligodendrogliomas.

Controversies in the Therapy of Low-Grade Gliomas

OPINION STATEMENT

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

Neuro-Oncology Clinical Debate: PCV or temozolomide in combination with radiation for newly diagnosed high-grade oligodendroglioma

The treatment of newly diagnosed oligodendroglioma has been revolutionized in the past decade by multiple studies demonstrating that the addition of chemotherapy to radiation therapy results in a significant survival benefit. While the most direct evidence comes from clinical trials that utilized PCV, a chemotherapy regimen consisting of procarbazine, CCNU (lomustine), and vincristine, there is circumstantial evidence suggesting that the oral agent temozolomide (TMZ), which is both better tolerated and logistically simpler than PCV, may also be effective. The lack of currently available direct comparative data for PCV vs TMZ results in a diversity of practice. In this article, Ruff and Buckner argue for PCV as part of the standard-of-care regimen for newly diagnosed anaplastic oligodendroglioma, while Geurts and van den Bent defend the use of TMZ.

Multidisciplinary Treatment of Pediatric Low-Grade Glioma: Experience of Children Cancer Hospital of Egypt; 2007-2012

Background: Pediatric gliomas comprise a clinically, histologically, and molecularly heterogeneous group of central nervous system tumors. The survival of children with gliomas influenced by histologic subtype, age, and extent of resection. Tumor grade emerged as the most determinant of survival except in the young age groups. The aim of this study was to evaluate the role of multidisciplinary therapeutic approach including surgery and chemotherapy, and their impact on the outcome in pediatric patients with low-grade glioma (LGG). Procedure: Study patients were prospectively enrolled onto the study. All patients were below 18-year-old, diagnosed as LGG between July 2007 and June 2012. Upfront surgical resection was attempted in all tumors other than optic pathway sites. Systemic chemotherapy was given according to CCG-A9952 protocol. Results: Total/near-total resection in 105/227 (46.3%) without adjuvant treatment, while 49/227 patients (21.5%) underwent subtotal tumor resection followed by chemotherapy for big residual (n = 26). Follow-up only was indicated for asymptomatic/small residual (n = 23). The radiological diagnosis was set in 18/227 (7.9%) patients; 13/18 had optic pathway glioma. The 3-year overall survival (OS) was 87.3% versus 65.5% event free survival (EFS) for the whole study patients with a follow-up period of 1–5 years. The OS and EFS for patients who did surgery with no adjuvant treatment (n = 128) were, respectively, 95.2% and 77.3% versus 87.4% and 65.1% for adjuvant chemotherapy group (n = 99); (P = 0.015 and P = 0.016 for OS and EFS, respectively). Conclusion: Pediatric LGGs comprise a wide spectrum of pathological and anatomical entities that carry a high rate of prolonged survival among children and adolescents. Surgical resection is the mainstay of treatment in most of tumors. Combined chemotherapy can be an acceptable alternative when surgery is not safely feasible.

Procarbazine, CCNU and vincristine (PCV) versus temozolomide chemotherapy for patients with low-grade glioma: a systematic review

Low-grade gliomas (LGG) encompass a heterogeneous group of tumors that are clinically, histologically and molecularly diverse. Treatment decisions for patients with LGG are directed toward improving upon the natural history while limiting treatment-associated toxiceffects. Recent evidence has documented a utility for adjuvant chemotherapy with procarbazine, CCNU (lomustine), and vincristine (PCV) or temozolomide (TMZ). We sought to determine the comparative utility of PCV and TMZ for patients with LGG, particularly in context of molecular subtype. A literature search of PubMed was conducted to identify studies reporting patient response to PCV, TMZ, or a combination of chemotherapy and radiation therapy (RT). Eligibility criteria included patients 16 years of age and older, notation of LGG subtype, and report of progression-free survival (PFS), overall survival (OS), and treatment course. Level I, II, and III data were included. Adjuvant therapy with PCV resulted in prolonged PFS and OS in patients with newly diagnosed high-risk LGG. This benefit was accrued most significantly by patients with tumors harboring 1p/19q codeletion and IDH1 mutation. Adjuvant therapy with temozolomide was associated with lower toxicity than therapy with PCV. In patients with LGG with an unfavorable natural history, such as with intact 1p/19q and wild-type IDH1, RT/TMZ plus adjuvant TMZ may be the best option. Patients with biologically favorable high-risk LGG are likely to derive the most benefit from RT and adjuvant PCV.

Primary brain tumours in adults

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

Grade II and III Oligodendroglioma and Astrocytoma

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

Long-Term Outcome of Postoperative Irradiation in Patients with Newly Diagnosed WHO Grade III Anaplastic Gliomas

Purpose

Patients with anaplastic gliomas have a more favorable overall survival than patients with glioblastomas. In most analyses, WHO grade III and IV tumors are not analyzed separately. The present analysis reports outcome after postoperative radiotherapy in patients with WHO grade III gliomas.

Patients and methods

Between January 1988 and January 2007, 127 patients with WHO grade III tumors were treated with radiotherapy; the histological classification was pure astrocytoma in 104 patients, oligoastrocytoma in 12 and pure oligodendroglioma in 11 patients. Median age was 48 years. After the primary diagnosis, a biopsy had been performed in 72 patients; subtotal and total resections were performed in 37 and 18 patients, respectively. In all patients radiotherapy was applied with a median dose of 60 Gy in conventional fractionation. The median follow-up time was 18 months.

Results

Median overall survival was 17 months. Overall survival was significantly influenced by the extent of surgery. Median overall survival was 32 months after complete resection, 36 months after subtotal resection, and 12 months after biopsy. Median overall survival was 7 months for patients with anaplastic astrocytomas, 44 months for patients with mixed tumors, and 47 months for those with pure oligodendrogliomas. Age significantly influenced overall survival. Median progression-free survival was 9 months; the extent of neurosurgical resection significantly influenced progression-free survival.

Conclusion

Patients with WHO grade III anaplastic astrocytomas, oligodendrogliomas and oligoastrocytomas show favorable overall survival after postoperative radiotherapy compared with glioblastoma patients and should therefore be analyzed separately. Radiochemotherapy might further improve outcome.

Recent advances in nanomedicine and survivin targeting in brain cancers

Brain cancer is a highly lethal disease, especially devastating toward both the elderly and children. This cancer has no therapeutics available to combat it, predominately due to the blood-brain barrier (BBB) preventing treatments from maintaining therapeutic levels within the brain. Recently, nanoparticle technology has entered the forefront of cancer therapy due to its ability to deliver therapeutic effects while potentially passing physiological barriers. Key nanoparticles for brain cancer treatment include glutathione targeted PEGylated liposomes, gold nanoparticles, superparamagnetic iron oxide nanoparticles and nanoparticle-albumin bound drugs, with these being discussed throughout this review. Recently, the survivin protein has gained attention as it is over-expressed in a majority of tumors. This review will briefly discuss the properties of survivin, while focusing on how both nanoparticles and survivin-targeting treatments hold potential as brain cancer therapies. This review may provide useful insight into new brain cancer treatment options, particularly survivin inhibition and nanomedicine.

Chemotherapy for adult low-grade gliomas: clinical outcomes by molecular subtype in a phase II study of adjuvant temozolomide

Background

Optimal adjuvant management of adult low-grade gliomas is controversial. Recently described tumor classification based on molecular subtype has the potential to individualize adjuvant therapy but has not yet been evaluated as part of a prospective trial.

Methods

Patients aged 18 or older with newly diagnosed World Health Organization grade II low-grade gliomas and gross residual disease after surgical resection were enrolled in the study. Patients received monthly cycles of temozolomide for up to 1 year or until disease progression. For patients with available tissue, molecular subtype was assessed based upon 1p/19q codeletion and isocitrate dehydrogenase-1 R132H mutation status. The primary outcome was radiographic response rate; secondary outcomes included progression-free survival (PFS) and overall survival (OS).

Results

One hundred twenty patients were enrolled with median follow-up of 7.5 years. Overall response rate was 6%, with median PFS and OS of 4.2 and 9.7 years, respectively. Molecular subtype was associated with rate of disease progression during treatment (P<.001), PFS (P=.007), and OS (P<.001). Patients with 1p/19q codeletion demonstrated a 0% risk of progression during treatment. In an exploratory analysis, pretreatment lesion volume was associated with both PFS (P<.001) and OS (P<.001).

Conclusions

While our study failed to meet the primary endpoint for objective radiographic response, patients with high-risk low-grade glioma receiving adjuvant temozolomide demonstrated a high rate of radiographic stability and favorable survival outcomes while meaningfully delaying radiotherapy. Patients with 1p/19q codeletion are potential candidates for omission of adjuvant radiotherapy, but further work is needed to directly compare chemotherapy with combined modality therapy.

Probing the phosphatidylinositol 3-kinase/mammalian target of rapamycin pathway in gliomas: A phase 2 study of everolimus for recurrent adult low-grade gliomas

BACKGROUND

Activation of the phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway is common in patients with low-grade gliomas (LGGs), but agents that inhibit this pathway, including mTOR inhibitors, have not been studied in this population.

METHODS

Fifty-eight patients with pathologic evidence of recurrence after they had initially been diagnosed with World Health Organization (WHO) grade II gliomas were enrolled into a prospective phase 2 clinical trial and received daily everolimus (RAD001) for 1 year or until progression. Tissue at the time of enrollment was analyzed for markers of PI3K/mTOR pathway activation. Thirty-eight patients underwent serial multiparametric magnetic resonance imaging, with the tumor volume and the perfusion metrics (the fractional blood volume [fBV] for capillary density and the transfer coefficient [K_ps ] for vascular permeability) measured during treatment. The primary endpoint was progression-free survival at 6 months (PFS-6) in patients with WHO II disease at enrollment.

RESULTS

For patients with WHO II gliomas at enrollment, the PFS-6 rate was 84%, and this met the primary endpoint (P < .001 for an improvement from the historical rate of 17%). Evidence of PI3K/mTOR activation by immunohistochemistry for phosphorylated ribosomal S6^Ser240/244 (p-S6^Ser240/244 ) was associated with worse progression-free survival (PFS; hazard ratio [HR], 3.03; P = .004) and overall survival (HR, 12.7; P = .01). Tumor perfusion decreased after 6 months (median decrease in fBV, 15%; P = .03; median decrease in K_ps , 12%; P = .09), with greater decreases associated with improved PFS (HR for each 10% fBV decrease, 0.71; P = .01; HR for each 10% K_ps decrease, 0.82; P = .04).

CONCLUSIONS

Patients with recurrent LGGs demonstrated a high degree of disease stability during treatment with everolimus. PI3K/mTOR activation, as measured by immunohistochemistry for p-S6, was associated with a worse prognosis. Tumor vascular changes were observed that were consistent with the antiangiogenic effects of mTOR inhibitors. These results support further study of everolimus for LGGs. Cancer 2017;123:4631-4639. © 2017 American Cancer Society.

Diffuse Infiltrating Oligodendroglioma and Astrocytoma

The new 2016 WHO brain tumor classification defines different diffuse gliomas primarily according to the presence or absence of IDH mutations ( IDH-mt) and combined 1p/19q loss. Today, the diagnosis of anaplastic oligodendroglioma requires the presence of both IDH-mt and 1p/19q co-deletion, whereas anaplastic astrocytoma is divided into IDH wild-type ( IDH-wt) and IDH-mt tumors. IDH-mt tumors have a more favorable prognosis, and tumors with low-grade histology especially tend evolve slowly. IDH-wt tumors are not a homogeneous entity and warrant further molecular testing because some have glioblastoma-like molecular features with poor clinical outcome. Treatment consists of a resection that should be as extensive as safely possible, radiotherapy, and chemotherapy. Trials of patients with newly diagnosed grade II or III glioma have shown survival benefit from adding chemotherapy to radiotherapy compared with initial treatment using radiotherapy alone. Both temozolomide and the combination of procarbazine, lomustine, and vincristine provide survival benefit. In contrast, trials that compare single modality treatment of chemotherapy alone with radiotherapy alone did not observe survival differences. Currently, for patients with grade II or III gliomas who require postsurgical treatment, the preferred treatment consists of a combination of radiotherapy and chemotherapy. Low-grade gliomas with favorable characteristics are slow-growing tumors. When deciding on the timing of postsurgical treatment with radiotherapy and chemotherapy, both clinical and molecular factors should be taken into account, but a more conservative approach can be considered initially in some of these patients. The factor that best predicts benefit of chemotherapy in grade II and III glioma remains to be established.

Spinal Anaplastic Oligodendroglioma With Oligodendrogliomatosis: Molecular Markers and Management: Case Report

BACKGROUND AND IMPORTANCE

Spinal cord oligodendrogliomas are rare tumors, with a reported incidence varying between 0.8% and 4.7% of all spinal cord tumors and just over 50 cases reported in the literature. Of these, only 9 cases are histologically defined as anaplastic oligodendrogliomas, with few having complete molecular characterization. The diffuse tumor spread that can occur along the subarachnoid space with secondary invasion of the leptomeninges is called oligodendrogliomatosis and is associated with poor outcome.

CLINICAL PRESENTATION

A 68-year-old man with a history of lumbar stenosis status after lumbar decompression presented with new-onset right lower-extremity weakness. Magnetic resonance imaging demonstrated an intramedullary lesion from T9 to T12. During an attempted diagnostic biopsy, numerous intradural intramedullary lesions not present on magnetic resonance imaging were observed. Tissue biopsy demonstrated a 1p/19q-codeleted anaplastic oligodendroglioma with diffuse oligodendrogliomatosis. Postoperative treatment included 39.2-Gy radiation over 22 fractions from T1 to the bottom of the thecal sac with a boost to the T9-T12 area, the primary site of disease, to a total dose of 43.2 Gy in 24 fractions, followed by adjuvant temozolomide at a dose of 200 mg/m on days 1 to 5 in a 28-day cycle. At the 1-year follow-up, the patient demonstrated moderate neurological improvement.

CONCLUSION

Management, prognosis, and use of molecular data in the decision-making algorithm for these patients are discussed, together with a review of all cases of primary intradural intramedullary spinal anaplastic oligodendrogliomas reported to date. Our study indicates that the combination of sequential treatment with radiation and temozolomide might provide a favorable outcome in the case of 1p/19q-codeleted spinal anaplastic oligodendrogliomas and that molecular analysis can be beneficial in guiding treatment strategies, although the impact of IDH mutations on these tumors is still unclear.

The simulation of UV spectroscopy and electronic analysis of temozolomide and dacarbazine chemical decomposition to their metabolites

The electronic features of anti-tumor agent, temozolomide, and its degradation products (MTIC and metabolite AIC) have been traced by means of UV absorption spectroscopy in vacuo and aqueous media. For comparison, electronic spectra of related structures and drugs (e.g., dacarbazine) were also investigated. These investigations were carried out using time-dependent density functional theory (TD-DFT) method while the conductor like screening model (COSMO) were applied for the inclusion of solvent effects in electronic spectra. From functional benchmarking, two methods; B3LYP and O3LYP were selected among several other methods with 6-311+G(2d,p) basis set aiming to get the best results in accord with the experimental values. An assessment of the obtained spectra has shown that O3LYP functional gives a mean absolute error (MAE) from experimental absorption peaks of 4.3 nm compared to the 7.2 nm MAE value at B3LYP level in aqueous media. Furthermore, since the structural and tautomeric conformers affect the electronic spectra, conformational preferences have been analyzed in temozolomide, dacarbazine, and their related structures. Temozolomide structure possesses two rotamers that differ in the orientation of carboxamide moiety with a small energy difference (energy difference of 1.39 kcal mol^-1 in vacuo and 0.35 kcal mol^-1 in aqueous media at B3LYP/6-311++G(2df,3pd). The more stable and meta-stable TMZ rotamer have shown their absorption maxima at 329-334 nm, respectively, at O3LYP level in aqueous media. Applying statistical calculation according to Boltzmann population formula at 25 °C and computed weighed mean estimates the λ_max of temozolomide at 331 nm, which is in notable agreement with the experimental value (330 nm). Moreover, molecular orbital composition analysis has been conducted in order to interpret these findings. Graphical Abstract Temozolomide and dacarbazine.

Temozolomide for malignant gliomas in British Columbia: A population-based cost-effectiveness analysis

Study objectives. To evaluate the cost-effectiveness and outcomes achieved in patients with recurrent malignant glioma treated with temozolomide in British Columbia, as compared to previous lomustine use in the same patient population, and to temozolomide literature reports. Outcomes assessed included median overall survival, 6-month overall survival and 6-month progression free survival.

Methods. A retrospective analysis was conducted to identify patients who received single-agent temozolomide or lomustine during successive, prespecified time periods. Data was collected on survival, disease progression, duration of therapy, cost of drug, labour and supplies, and successive or prior chemotherapy.

Results. Six-month progression free survival (PFS) occurred in 52% and 42.9% of patients in the temozolomide and lomustine cohorts, respectively (P=0.44). Six-month overall survival and median overall survival (OS) were 72% and 40.86 weeks for temozolomide patients and 64.3% and 46.7 weeks for lomustine patients. These outcomes were not statistically different between the two treatment groups. Associated with these outcomes, temozolomide patients received a median of six cycles of drug treatment, with a median cost per patient of $11 660 (CAN). Alternatively, lomustine patients received a median of four cycles with a median cost per patient of $189 (CAN). In the cost-effectiveness analysis for median OS, temozolomide was not a cost-effective alternative, and for 6-month PFS, the incremental cost effectiveness ratio (ICER) of temozolomide was $1261 (CAN) for each additional percent of patients progression free at 6-months. Sensitivity analysis varying both median OS and 6-month PFS resulted in ICER’s of temozolomide ranging from $332 to $3277.

Conclusions. No significant differences in outcomes were observed between patients treated with single-agent lomustine or temozolomide. Temozolomide therapy has an incremental cost increase over lomustine of $11 471 per patient. It appears when only survival outcomes and direct treatment costs are considered, lomustine is a more cost-effective treatment strategy in the specific setting of recurrent malignant glioma.

Molecular Diagnostics as a Tool to Personalize Treatment in Adult Glioma Patients

Gliomas, the most frequent primary brain tumors in humans, form a heterogeneous group, encompassing many different histological types and malignancy grades. Within this group, the diffuse infiltrative gliomas are by far the most common in adults. The major representatives in this subgroup are the diffuse astrocytic, oligodendroglial, and mixed oligo-astrocytic tumors. Especially in these diffuse gliomas, the role of molecular diagnostics is rapidly increasing. After summarizing the most relevant genetic aberrations and pathways in these tumors detected up till now, this review will discuss the clinical relevance of this information. Several molecular markers have been identified in diffuse gliomas that carry diagnostic and prognostic information. In addition, some of these and other markers predict the response of these gliomas to particular (chemo)therapeutic approaches. The techniques used to obtain this molecular information, as well as the advantages and disadvantages of the different techniques will be discussed. Finally, future perspectives will be presented with regard to the contribution of molecular diagnostics to tailor-made therapy in glioma patients.

Current Management of Adult Diffuse Infiltrative Low Grade Gliomas

Diffuse infiltrative low grade gliomas (LGG) account for approximately 15 % of all gliomas. The prognosis of LGG differs between high-risk and low-risk patients notwithstanding varying definitions of what constitutes a high-risk patient. Maximal safe resection optimally is the initial treatment. Surgery that achieves a large volume resection improves both progression-free and overall survival. Based on results of three randomized clinical trials (RCT), radiotherapy (RT) may be deferred in patients with low-risk LGG (defined as age <40 years and having undergone a complete resection), although combined chemoradiotherapy has never been prospectively evaluated in the low-risk population. The recent RTOG 9802 RCT established a new standard of care in high-risk patients (defined as age >40 years or incomplete resection) by demonstrating a nearly twofold improvement in overall survival with the addition of PCV (procarbazine, CCNU, vincristine) chemotherapy following RT as compared to RT alone. Chemotherapy alone as a treatment of LGG may result in less toxicity than RT; however, this has only been prospectively studied once (EORTC 22033) in high-risk patients. A challenge remains to define when an aggressive treatment improves survival without impacting quality of life (QoL) or neurocognitive function and when an effective treatment can be delayed in order to preserve QoL without impacting survival. Current WHO histopathological classification is poorly predictive of outcome in patients with LGG. The integration of molecular biomarkers with histology will lead to an improved classification that more accurately reflects underlying tumor biology, prognosis, and hopefully best therapy.

Low-grade and anaplastic oligodendroglioma

Anaplastic oligodendrogliomas have long attracted interest because of their sensitivity to chemotherapy, in particular in the subset of 1p/19q co-deleted tumors. Recent molecular studies have shown that all 1p/19q co-deleted tumors have IDH mutations and most of them also have TERT mutations. Because of the presence of similar typical genetic alterations in astrocytoma and glioblastoma, the current trend is to diagnose these tumors on the basis of their molecular profile. Further long-term follow-up analysis of both EORTC and RTOG randomized studies on (neo)adjuvant procarbazine, lomustine, vincristine (PCV) chemotherapy have shown that adjuvant chemotherapy indeed improves outcome, and this is now standard of care. It is also equally clear that benefit to PCV chemotherapy is not limited to the 1p/19q co-deleted cases; potential other predictive factors are IDH mutations and MGMT promoter methylation. Moreover, a recent RTOG study on low-grade glioma also noted an improved outcome after adjuvant PCV chemotherapy, thus making (PCV) chemotherapy now standard of care for all 1p/19q co-deleted tumors regardless of grade. It remains unclear whether temozolomide provides the same survival benefit, as no data from well-designed clinical trials on adjuvant temozolomide in this tumor type are available. Another question that remains is whether one can safely leave out radiotherapy as part of initial treatment to avoid cognitive side-effects of radiotherapy. The current data suggest that delaying radiotherapy and treatment with chemotherapy only may be detrimental for overall survival.

Immunohistochemical analysis of O6-methylguanine-DNA methyltransferase (MGMT) protein expression as prognostic marker in glioblastoma patients treated with radiation therapy with concomitant and adjuvant Temozolomide

BACKGROUND

O6-methylguanine-DNA methyltransferase (MGMT) protein expression using immunohistochemical analysis was proposed as a prognostic marker for patients with newly diagnosed glioblastoma (GBM) treated with radiation therapy with concurrent and adjuvant Temozolomide (TMZ).

METHODS

From April 2012 to October 2014, 73 patients with newly diagnosed GBM, MGMT protein expression were analyzed in formalin-fixed, paraffin-embedded tumor specimens. Patients received the radiation therapy plus concomitant and adjuvant TMZ chemotherapy.

RESULTS

For the whole cohort, the median overall survival (OS) was 15 months, and the progression-free survival was 10 months. Patients who had low MGMT protein expression (⩽15%) had a significantly improved OS and PFS compared with patients who had high MGMT expression (17.0 months vs 14 months; P value .006) and (15.0 months vs 10 months; P value .016) respectively. The age and extent of tumor resection were the strongest clinical predictors of outcome. In multivariate Cox models MGMT protein expression, extent of tumor resection and age were identified as independent prognostic factors.

CONCLUSIONS

MGMT expression was identified as positive prognostic factor in patients with newly diagnosed glioblastoma who underwent surgical resection followed by adjuvant radiotherapy and concomitant oral TMZ chemotherapy (the Stupp protocol).

Management of patients with recurrence of diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline

TARGET POPULATION

These recommendations apply to adult patients with recurrent low-grade glioma (LGG) with initial pathologic diagnosis of a WHO grade II infiltrative glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma).

PATHOLOGY AT RECURRENCE

QUESTION

Do pathologic and molecular characteristics predict outcome/malignant transformation at recurrence?

RECOMMENDATIONS

IDH STATUS AND RECURRENCE: (Level III) IDH mutation status should be determined as LGGs with IDH mutations have a shortened time to recurrence. It is unclear whether knowledge of IDH mutation status provides benefit in predicting time to progression or overall survival. TP53 STATUS AND RECURRENCE: (Level III) TP53 mutations occur early in LGG pathogenesis, remain stable, and are not recommended as a marker of predisposition to malignant transformation at recurrence or other measures of prognosis. MGMT STATUS AND RECURRENCE: (Level III) Assessment of MGMT status is recommended as an adjunct to assessing prognosis as LGGs with MGMT promoter methylation are associated with shorter PFS (in the absence of TMZ) and longer post-recurrence survival (in the presence of TMZ), ultimately producing similar overall survival to LGGs without MGMT methylation. The available retrospective reports are conflicting and comparisons between reports are limited CDK2NA STATUS AND RECURRENCE: (Level III) Assessment of CDK2NA status is recommended when possible as the loss of expression of the CDK2NA via either methylation or loss of chromosome 9p is associated with malignant progression of LGGs. PROLIFERATIVE INDEX AND RECURRENCE: (Level III) It is recommended that proliferative indices (MIB-1 or BUdR) be measured in LGGs as higher proliferation indices are associated with increased likelihood of recurrence and shorter progression free and overall survival. 1P/19Q STATUS AND RECURRENCE: There is insufficient evidence to make any recommendations.

CHEMOTHERAPY AT RECURRENCE

QUESTION

What role does chemotherapy have in LGG recurrence?

RECOMMENDATIONS

TEMOZOLOMIDE AND RECURRENCE: (Level III) Temozolomide is recommended in the therapy of recurrent LGG as it may improve clinical symptoms. Oligodendrogliomas and tumors with 1p/19q co-deletion may derive the most benefit. PCV AND RECURRENCE: (Level III) PCV is recommended in the therapy of LGG at recurrence as it may improve clinical symptoms with the strongest evidence being for oligodendrogliomas. CARBOPLATIN AND RECURRENCE : (Level III) Carboplatin is not recommended as there is no significant benefit from carboplatin as single agent therapy for recurrent LGGs. OTHER TREATMENTS (NITROSUREAS, HYDROXYUREA/IMANITIB, IRINOTECAN, PACLITAXEL) AND RECURRENCE: There is insufficient evidence to make any recommendations. It is recommended that individuals with recurrent LGGs be enrolled in a properly designed clinical trial to assess these chemotherapeutic agents.

RADIATION AT RECURRENCE

QUESTION

What role does radiation have in LGG recurrence?

RECOMMENDATIONS

RADIATION AT RECURRENCE WITH NO PREVIOUS IRRADIATION: (Level III) Radiation is recommended at recurrence if there was no previous radiation treatment. RE-IRRADIATION AT RECURRENCE: (Level III) It is recommended that re-irradiation be considered in the setting of LGG recurrence as it may provide benefit in disease control.

SURGERY AT RECURRENCE

There is insufficient evidence to make any specific recommendations. It is recommended that individuals with recurrent LGGs be enrolled in a properly designed clinical trial to assess the role of surgery at recurrence.

Procarbazine, lomustine and vincristine or temozolomide: which is the better regimen?

Anaplastic oligodendrogliomas (AOs) are rare brain tumors responsive to chemotherapy with procarbazine, lomustine (CCNU) and vincristine (PCV), especially when harboring 1p19q codeletion. However, with the emergence of temozolomide as an easier to administer and less toxic alternative regimen, PCV fell out of favor. Now, long-term results of two Phase III studies conceived in the 1990s, Radiation Therapy Oncology Group (RTOG) 9402 and European Organisation for Research and Treatment of Cancer (EORTC) 26951, resurrected debate about the potential role of PCV. No adequately powered prospective trial has compared chemotherapy alone with PCV versus temozolomide for newly diagnosed 1p19q codeleted AOs. Available data suggest responses may be both more frequent and more durable with PCV, and survival may be longer. Which regimen is 'better', therefore, depends on the importance of different metrics (i.e., toxicity, complexity, efficacy), and await definitive results from the important ongoing and recently redesigned CODEL international Phase III trial.

Radiation therapy and grade II/III oligodendroglial tumors

Radiotherapy has been a longstanding treatment option for low-grade glioma. Improvements in tumor control and radiation-related toxicity may be attributed to advances in neuroimaging as well as radiotherapy planning and delivery. The discovery of various molecular prognostic factors have aided in patient selection for radiotherapy. These prognostic and predictive factors may also play a key role in determining which patients are likely to benefit most from combined systemic therapy and radiation.

Neurosurgical management of adult diffuse low grade gliomas in Canada: a multi-center survey

Adult diffuse low-grade gliomas are slow growing, World Health Organization grade II lesions with insidious onset and ultimate anaplastic transformation. The timing of surgery remains controversial with polarized practices continuing to govern patient management. As a result, the management of these patients is variable. The goal of this questionnaire was to evaluate practice patterns in Canada. An online invitation for a questionnaire including diagnostic, preoperative, perioperative, and postoperative parameters and three cases with magnetic resonance imaging data with questions to various treatment options in these patients was sent to practicing neurosurgeons and trainees. Survey was sent to 356 email addresses with 87 (24.7 %) responses collected. The range of years of practice was less than 10 years 36 % (n = 23), 11–20 years 28 % (n = 18), over 21 years 37 % (n = 24). Twenty-two neurosurgery students of various years of training completed the survey. 94 % (n = 47) of surgeons and trainees (n = 20) believe that we do not know the “right treatment”. 90 % of surgeons do not obtain formal preoperative neurocognitive assessments. 21 % (n = 13) of surgeons and 23 % of trainees (n = 5) perform a biopsy upon first presentation. A gross total resection was believed to increase progression free survival (surgeons: 75 %, n = 46; trainees: 95 %, n = 21) and to increase overall survival (surgeons: 64 %, n = 39, trainees: 68 %, n = 15). Intraoperative MRI was only used by 8 % of surgeons. Awake craniotomy was the procedure of choice for eloquent tumors by 80 % (n = 48) of surgeons and 100 % of trainees. Of those surgeons who perform awake craniotomy 93 % perform cortical stimulation and 38 % performed subcortical stimulation. Using the aid of three hypothetical cases with progressive complexities in tumor eloquence there was a trend for younger surgeons to operate earlier, and use awake craniotomy to obtain greater extent of resection with the aid of cortical stimulation when compared to senior surgeons who still more often preferred a “wait-and-see” approach. Despite the limitations of an online survey study, it has offered insights into the variability in surgeon practice patterns in Canada and the need for a consensus on the workup and surgical management of this disease.

A multicenter study of anaplastic oligodendroglioma: the Korean Radiation Oncology Group Study 13-12

Although some existing evidence supports the addition of chemotherapy (CT) to radiation therapy (RT) for anaplastic oligodendroglioma treatment, controversy about both the criteria for suitable candidates and the optimal treatment schedule remains. We reviewed data from 376 newly diagnosed anaplastic oliogodendroglial tumor patients from nine Korean institutes were reviewed from 2000 to 2010. Total tumor removal was performed in 146 patients. More than 85% of the entire patients received postoperative RT, and 59% received CT. Approximately 50% (n = 189) received CT in addition to RT and 9% (n = 32) received CT only. A multivariate analysis revealed that younger age, frontal lobe location of the tumor, gross total removal, 1p/19q codeletion, and initial RT were associated with longer progression-free and overall survival rates. No difference was observed in outcomes from the treatment that included either temozolomide or PCV (procarbazine, lomustine, and vincristine) in addition to RT regardless of the 1p/19q deletion status. A clear improvement in progression-free and overall survival was observed for RT and combined CT/RT in compared with CT only. Postoperative RT appears to improve survival for entire group thus total removal and 1p/19q codeletion may not be sufficient criteria to omit RT as a treatment option. These results suggest that RT should continue to be offered as the standard treatment option for patients with anaplastic oligodendroglial tumors.

Phase II trial of pre-irradiation and concurrent temozolomide in patients with newly diagnosed anaplastic oligodendrogliomas and mixed anaplastic oligoastrocytomas: long term results of RTOG BR0131

We report on the long-term results of a phase II study of pre-irradiation temozolomide followed by concurrent temozolomide and radiotherapy (RT) in patients with newly diagnosed anaplastic oligodendroglioma (AO) and mixed anaplastic oligoastrocytoma. Pre-RT temozolomide was given for up to 6 cycles. RT with concurrent temozolomide was administered to patients with less than a complete radiographic response. Forty eligible patients were entered and 32 completed protocol treatment. With a median follow-up time of 8.7 years (range 1.1-10.1), median progression-free survival (PFS) is 5.8 years (95 % CI 2.0, NR) and median overall survival (OS) has not been reached (5.9, NR). 1p/19q data are available in 37 cases; 23 tumors had codeletion while 14 tumors had no loss or loss of only 1p or 19q (non-codeleted). In codeleted patients, 9 patients have progressed and 4 have died; neither median PFS nor OS have been reached and two patients who received only pre-RT temozolomide and no RT have remained progression-free for over 7 years. 3-year PFS and 6-year OS are 78 % (95 % CI 61-95 %) and 83 % (95 % CI 67-98 %), respectively. Codeleted patients show a trend towards improved 6-year survival when compared to the codeleted procarbazine/CCNU/vincristrine (PCV) and RT cohort in RTOG 9402 (67 %, 95 % CI 55-79 %). For non-codeleted patients, median PFS and OS are 1.3 and 5.8 years, respectively. These updated results suggest that the regimen of dose intense, pre-RT temozolomide followed by concurrent RT/temozolomide has significant activity, particularly in patients with 1p/19q codeleted AOs and MAOs.

Clinical management of grade III oligodendroglioma

Oligodendrogliomas represent the third most common type of glioma, comprising 4%-15% of all gliomas and can be classified by degree of malignancy into grade II and grade III, according to WHO classification. Only 30% of oligodendroglial tumors have anaplastic characteristics. Anaplastic oligodendroglioma (AO) is often localized as a single lesion in the white matter and in the cortex, rarely in brainstem or spinal cord. The management of AO is deeply changed in the recent years. Maximal safe surgical resection followed by radiotherapy (RT) was considered as the standard of care since paramount findings regarding molecular aspects, in particular co-deletion of the short arm of chromosome 1 and the long arm of chromosome 19, revealed that these subsets of AO, benefit in terms of overall survival (OS) and progression-free survival (PFS), from the addition of chemotherapy to RT. Allelic losses of chromosomes 1p and 19q occur in 50%-70% of both low-grade and anaplastic tumors, representing a strong prognostic factor and a powerful predictor of prolonged survival. Several other molecular markers have potential clinical significance as IDH1 mutations, confirming the strong prognostic role for OS. Malignant brain tumors negatively impacts on patients' quality of life. Seizures, visual impairment, headache, and cognitive disorders can be present. Moreover, chemotherapy and RT have important side effects. For these reasons, "health-related quality of life" is becoming a topic of growing interest, investigating on physical, mental, emotional, and social well-being. Understanding the impact of medical treatment on health-related quality of life will probably have a growing effect both on health care strategies and on patients.

Molecular Markers in Low-Grade Glioma-Toward Tumor Reclassification

Low-grade diffuse gliomas are a heterogeneous group of primary glial brain tumors with highly variable survival. Currently, patients with low-grade diffuse gliomas are stratified into risk subgroups by subjective histopathologic criteria with significant interobserver variability. Several key molecular signatures have emerged as diagnostic, prognostic, and predictor biomarkers for tumor classification and patient risk stratification. In this review, we discuss the effect of the most critical molecular alterations described in diffuse (IDH1/2, 1p/19q codeletion, ATRX, TERT, CIC, and FUBP1) and circumscribed (BRAF-KIAA1549, BRAF(V600E), and C11orf95-RELA fusion) gliomas. These molecular features reflect tumor heterogeneity and have specific associations with patient outcome that determine appropriate patient management. This has led to an important, fundamental shift toward developing a molecular classification of World Health Organization grade II-III diffuse glioma.

Anaplastic glioma: current treatment and management

Anaplastic glioma (AG) is divided into three morphology-based groups (anaplastic astrocytoma, anaplastic oligodendroglioma, anaplastic oligoastrocytoma) as well as three molecular groups (glioma-CpG island methylation phenotype [G-CIMP] negative, G-CIMP positive non-1p19q codeleted tumors and G-CIMP positive codeleted tumors). The RTOG 9402 and EORTC 26951 trials established radiotherapy plus (procarbazine, lomustine, vincristine) chemotherapy as the standard of care in 1p/19q codeleted AG. Uni- or non-codeleted AG are currently best treated with radiotherapy only or alkylator-based chemotherapy only as determined by the NOA-04 trial. Maturation of NOA-04 and results of the currently accruing studies, CODEL (for codeleted AG) and CATNON (for uni or non-codeleted AG), will likely refine current up-front treatment recommendations for AG.

Chemotherapy in glioma

The treatment of glial brain tumors begins with surgery, and standard adjuvant treatment at the end of the past millennium for high-grade glioma and high-risk low-grade glioma was radiotherapy and chemotherapy was given at recurrence. However, over the past 10 years much has changed regarding the role of chemotherapy in gliomas and it is now clear that chemotherapy has a role in the treatment of almost all newly diagnosed diffuse gliomas (WHO grade II-IV). This is the result of several prospective studies that showed survival benefit after combined chemoradiotherapy with temozolomide in glioblastoma (WHO grade IV) or after procarbazine, CCNU (lomustine) and vincristine chemotherapy in diffuse low-grade (WHO grade II) and anaplastic (WHO grade III) glioma. The current standard of treatment for diffuse gliomas is described in this overview and in addition some attention is given to targeted therapies.

Surgical management of high-grade glioma: a standard of care

Neurosurgical oncology for intrinsic glioma is evolving rapidly. It must be patient-centered, consultant-led and research-orientated. The value of specialist neurosurgical engagement is becoming more widely recognized. Detailed evaluation tailored to each patient is essential before the surgical admission, in conjunction with clinical oncology input. Medical optimization, collation of magnetic resonance datasets for preoperative planning and providing an informed explanation of the proposed management and its alternatives are all part of the neurosurgeon's remit. Meticulous microsurgical technique during surgery utilizing modern neuronavigation and physiological monitoring are integral components of the specialist armamentarium. A clear understanding of the rationale for surgical intervention, including its place alongside radiotherapy and chemotherapy, informs surgical decision-making. Recognition and understanding of these issues are driving the evolution of neurosurgical management of high-grade glioma. New challenges are emerging and need to be critically evaluated in robustly designed clinical trials.

Radiation Therapy Oncology Group 9802: Controversy or Consensus in the Treatment of Newly Diagnosed Low-Grade Glioma?

Treatment of newly diagnosed or suspected low-grade glioma (LGG) is one of the most controversial areas in neuro-oncology. The heterogeneity of these tumors, concern regarding morbidity of treatment, and absence of proven overall survival benefit from any known treatment have resulted in a lack of consensus regarding the timing and extent of surgery, timing of radiotherapy (RT), and role of chemotherapy. The long-term results of Radiation Therapy Oncology Group (RTOG) 9802, a phase III randomized trial comparing RT alone with RT and 6 cycles of adjuvant procarbazine, CCNU, vincristine (PCV), demonstrated an unprecedented 5.5-year improvement in median overall survival with the addition of PCV chemotherapy in high-risk patients with LGG. These results are practice changing and define a new standard of care for these patients. However, in the intervening decade since the trial was completed, novel molecular markers as well as newer chemotherapy agents such as temozolomide have been developed, which make these results difficult to incorporate into clinical practice. This review summarizes the evidence for and against the role of upfront RT and PCV in newly diagnosed patients with LGG.