Benefit from procarbazine, lomustine, and vincristine in oligodendroglial tumors is associated with mutation of IDH

Surgical outcomes in high-grade adult type diffuse gliomas (ATDG) with a previous diagnosis of anaplastic astrocytoma without adjuvant therapy

INTRODUCTION

Gliomas pose a significant treatment challenge due to their varied genetic makeup and clinical presentations. This study examines a unique cohort of high-grade adult type diffuse gliomas (ATDG) previously diagnosed as anaplastic astrocytoma prior to the WHO 2021 tumor classification changes. This cohort chose to undergo only surgical resection without adjuvant therapies. We provide a rare dataset of patients allowing for new insight into the natural progression of this disease with surgical treatment alone.

METHODS

A retrospective review was conducted of patients who were operated on by a single surgeon from the years 2002-2022 and who were diagnosed as having a Grade III Anaplastic Astrocytoma before the WHO 2021 guidelines were published. Correcting for the criteria in the 2021 Guidelines resulted in a mixture of adult-type diffuse malignant gliomas (ATDG), including IDH-Mutant astrocytomas (Grade 3 and 4) and IDH-WT Glioblastoma. All patients included underwent surgical resection alone after declining any adjuvant therapy for various reasons.

RESULTS

A total of 20 patients met the inclusion criteria with an average age of 38 years. Among them, 15 had IDH-mutant (IDH-mt) Grade 3 astrocytomas (75 %), 1 had an IDH-mt Grade 4 astrocytoma (5 %), and 4 had IDH-wildtype (IDH-WT) glioblastomas (20 %). The 5-year survival rate for the entire cohort was 74.0 %. Grade 3 astrocytomas had a 5-year survival of 86.7 %, while Grade 4 astrocytomas and IDH-WT GBM patients exhibited a 5-year survival rate of 40 %. 5-year progression-free survival (PFS) rates were derived from the surgery date up until the recurrence or censorship. The collective cohort had a PFS rate of 34.3 %. Grade 3 astrocytomas achieved a 5-year PFS of 32.0 %, whereas Grade 4 astrocytomas and IDH-WT GBM reached a PFS of 40.0 %.

CONCLUSION

In our cohort study, we demonstrate that patients with ATDG can potentially achieve relative long-term survival through surgical resection alone. This unique cohort highlights the natural progression of this disease with surgery alone and provides the foundation for future more rigorous studies to evaluate the additive benefit of different adjuvant therapies. With evolving tumor classifications and variable responses to standard therapeutics, it becomes imperative to revisit and understand the additive benefits of different chemotherapeutic protocols in addition to surgical resection.

Metabolism and therapeutic response in acute myeloid leukemia with IDH1/2 mutations

Pathogenic variants of isocitrate dehydrogenase 1 and 2 (IDH1/2) genes are present in approximately 20% of acute myeloid leukemia (AML) cases, resulting in the oncometabolite R-2-hydroxyglutarate (R-2-HG). The accumulation of R-2-HG in leukemic cells and in their niche induces epigenetic modifications, profound rewiring of the cellular metabolism, and microenvironmental remodeling. These changes promote cellular differentiation bias, enhancing the survival and proliferation of leukemic cells, and thus playing a pivotal role in leukemogenesis and resistance to standard AML therapy. This review focuses on the different perspectives offered by studying metabolism and resistance to standard treatments in AML with IDH1 or IDH2 pathogenic variants, for the development of new biomarkers and therapeutic solutions.

Precision radiotherapy with molecular-profiling of CNS tumours

Diagnoses of CNS malignancies in the primary and metastatic setting have significantly advanced in the last decade with the advent of molecular pathology. Using a combination of immunohistochemistry, next-generation sequencing, and methylation profiling integrated with traditional histopathology, patient prognosis and disease characteristics can be understood to a much greater extent. This has recently manifested in predicting response to targeted drug therapies that are redefining management practices of CNS tumours. Radiotherapy, along with surgery, still remains an integral part of treating the majority of CNS tumours. However, the rapid advances in CNS molecular diagnostics have not yet been effectively translated into improving CNS radiotherapy. We explore several promising strategies under development to integrate molecular oncology into radiotherapy, and explore future directions that can serve to use molecular diagnostics to personalize radiotherapy. Evolving the management of CNS tumours with molecular profiling will be integral to supporting the future of precision radiotherapy.

Management of Low-Grade Gliomas

ABSTRACT

The term "low-grade glioma" historically refers to adult diffuse gliomas that exhibit a less aggressive course than the more common high-grade gliomas. In the current molecular era, "low-grade" refers to World Health Organization central nervous system grade 2 gliomas almost always with an isocitrate dehydrogenase (IDH) mutation (astrocytomas and oligodendrogliomas). The term "lower-grade gliomas" has emerged encompassing grades 2 and 3 IDH-mutant astrocytomas and oligodendrogliomas, to acknowledge that histological grade is not as important a prognostic factor as molecular features, and distinguishing them from grade 4 glioblastomas, which lack an IDH mutation. These grades 2 and 3 IDH-mutant tumors are characterized by indolent growth but are ultimately incurable in most cases, presenting significant management challenges. Physicians must carefully weigh all available evidence to balance improvements in survival from new treatments against treatment toxicities. This review summarizes the evidence guiding the treatment of these patients.

Recent Advancements and Future Perspectives on Molecular Biomarkers in Adult Lower-Grade Gliomas

ABSTRACT

There has been a significant paradigm shift in the clinical management of lower-grade glioma patients given the recent updates to the 2021 World Health Organization classification along with long-term results from randomized phase III clinical trials. As a result, we are now better able to diagnose and assign patients to the most appropriate treatment course. This review provides a comprehensive summary of the most robust and reliable molecular biomarkers for adult lower-grade gliomas and discusses current challenges facing this patient population that future correlative biology studies combined with advancements in technologies could help overcome.

Mapping glioma's impact on cognition: Insights from macrostructure, microstructure, and beyond

Background

Cognitive impairment (CI) significantly impacts the quality of life of glioma patients. The main contributing risk factors include tumor characteristics, treatment-related factors, and their complex interplay. This review explores the role of advanced structural neuroimaging techniques in understanding CI in glioma patients.

Methods

A literature search was conducted in PubMed, PsycINFO, and ISI Web of Knowledge using specific keywords. We included studies with advanced magnetic resonance imaging techniques and objective neuropsychological exams.

Results

At diagnosis, during the pre-surgery phase, associations between glioma characteristics and cognitive outcomes have been described. Specifically, patients with isocitrate dehydrogenase (IDH)-wild-type gliomas exhibit more adverse cognitive outcomes, accompanied by disruptions in gray (GM) and white matter (WM) networks when compared to IDH-mutant. In addition, pre- and post-surgery imaging analyses highlight the importance of preserving specific WM tracts, such as the inferior longitudinal and arcuate fasciculus, in mitigating verbal memory and language processing decline. Furthermore, examining gliomas in perisylvian regions emphasizes deleterious effects on various cognitive domains. Additionally, it has been suggested that neuroplastic reorganization could serve as a compensatory mechanism against CI. Lastly, a limited number of studies suggest long-term CI linked to GM atrophy and leukoencephalopathy induced by radiotherapy ± chemotherapy in glioma survivors, highlighting the need for improving treatment approaches, particularly for patients with extended survival expectations.

Conclusion

This review underscores the need for nuanced understanding and an individual approach in the management of glioma patients. Neuroplastic insights offer clinicians valuable guidance in surgical decision-making and personalized therapeutic approaches thus improving patient outcomes in neuro-oncology.

Advances in the treatment of IDH-mutant gliomas

PURPOSE OF REVIEW

Isocitrate dehydrogenase (IDH) mutation is a defining molecular driver of WHO grade 2-4 astrocytomas and oligodendrogliomas. In this article, we review the recent therapeutic approaches specifically targeting IDH-mutant gliomas and summarize ongoing clinical trials in this population.

RECENT FINDINGS

The IDH inhibitor vorasidenib recently demonstrated its efficacy after surgical resection in grade 2 IDH-mutated gliomas. Several studies in patients with IDH-mutant gliomas are currently exploring various strategies to target IDH mutations, including the use of small-molecule inhibitors, immunotherapies, peptide vaccines and agents targeting metabolic and epigenomic vulnerabilities.

SUMMARY

Mutant-IDH targeting holds significant promise in treating progressive or recurrent IDH-mutant gliomas. Recent results with IDH inhibitors will change practice and influence the existing guidelines in a near future.

Star wars against leukemia: attacking the clones

Leukemia, although most likely starts as a monoclonal genetic/epigenetic anomaly, is a polyclonal disease at manifestation. This polyclonal nature results from ongoing evolutionary changes in the genome/epigenome of leukemia cells to promote their survival and proliferation advantages. We discuss here how genetic and/or epigenetic aberrations alter intracellular microenvironment in individual leukemia clones and how extracellular microenvironment selects the best fitted clones. This dynamic polyclonal composition of leukemia makes designing an effective therapy a challenging task especially because individual leukemia clones often display substantial differences in response to treatment. Here, we discuss novel therapeutic approach employing single cell multiomics to identify and eradicate all individual clones in a patient.

Functional germline variants in DNA damage repair pathways are associated with altered survival in adults with glioma treated with temozolomide

Background

Temozolomide (TMZ) treatment has demonstrated, but variable, impact on glioma prognosis. This study examines associations of survival with DNA repair gene germline polymorphisms among glioma patients who did and did not have TMZ treatment. Identifying genetic markers which sensitize tumor cells to TMZ could personalize therapy and improve outcomes.

Methods

We evaluated TMZ-related survival associations of pathogenic germline SNPs and genetically predicted transcript levels within 34 DNA repair genes among 1504 glioma patients from the UCSF Adult Glioma Study and Mayo Clinic whose diagnoses spanned pre- and post-TMZ eras within the major known glioma prognostic molecular subtypes.

Results

Among those who received TMZ, 5 SNPs were associated with overall survival, but not in those who did not receive TMZ. Only rs2308321-G, in MGMT, was associated with decreased survival (HR=1.21, p=0.019) for all glioma subtypes. Rs73191162-T (near UNG), rs13076508-C (near PARP3), rs7840433-A (near NEIL2), and rs3130618-A (near MSH5) were only associated with survival and TMZ treatment for certain subtypes, suggesting subtype-specific germline chemo-sensitization.Genetically predicted elevated compared to normal brain expression of PNKP was associated with dramatically worse survival for TMZ-treated patients with IDH-mutant and 1p/19q non-codeleted gliomas (p=0.015). Similarly, NEIL2 and TDG expressions were associated with altered TMZ-related survival only among certain subtypes.

Conclusions

Functional germline alterations within DNA repair genes were associated with TMZ sensitivity, measured by overall survival, among adults with glioma, these variants should be evaluated in prospective analyses and functional studies.

The IDH paradox: Meta-analysis of alkylating chemotherapy in IDH-wild type and -mutant lower grade gliomas

BACKGROUND

IDH-wild type (-wt) status is a prerequisite for the diagnosis of glioblastoma (GBM); however, IDH-wt gliomas with low-grade or anaplastic morphology have historically been excluded from GBM trials and may represent a distinct prognostic entity. While alkylating agent chemotherapy improves overall survival (OS) and progression-free survival (PFS) for IDH-wt GBM and also IDH-mutant gliomas, irrespective of grade, the benefit for IDH-wt diffuse histologic lower-grade gliomas is unclear.

METHODS

We performed a meta-analysis of randomized clinical trials for World Health Organization (WHO) grades 2-3 gliomas (2009 to present) to determine the effect of alkylating chemotherapy on IDH-wt and -mutant gliomas using a random-effects model with inverse-variance pooling.

RESULTS

We identified 6 trials with 1204 patients (430 IDH-wt, 774 IDH-mutant) that evaluated alkylating chemoradiotherapy versus radiotherapy alone, allowing us to perform an analysis focused on the value of adding alkylating chemotherapy to radiotherapy. For patients with IDH-wt tumors, alkylating chemotherapy added to radiotherapy was associated with improved PFS (HR:0.77 [95% CI: 0.62-0.97], P = .03) but not OS (HR:0.87 [95% CI: 0.64-1.18], P = .17). For patients with IDH-mutant tumors, alkylating chemotherapy added to radiotherapy improved both OS (HR:0.52 [95% CI: 0.42-0.64], P < .001) and PFS (HR = 0.47 [95% CI: 0.39-0.57], P < .001) compared to radiotherapy alone. The magnitude of benefit was similar for IDH-mutant gliomas with or without 1p19q-codeletion.

CONCLUSIONS

Alkylating chemotherapy reduces mortality by 48% and progression by 53% for patients with IDH-mutant gliomas. Optimal management of IDH-wt diffuse histologic lower-grade gliomas remains to be determined, as there is little evidence supporting an OS benefit from alkylating chemotherapy.

Emerging and Biological Concepts in Pediatric High-Grade Gliomas

Primary central nervous system tumors are the most frequent solid tumors in children, accounting for over 40% of all childhood brain tumor deaths, specifically high-grade gliomas. Compared with pediatric low-grade gliomas (pLGGs), pediatric high-grade gliomas (pHGGs) have an abysmal survival rate. The WHO CNS classification identifies four subtypes of pHGGs, including Grade 4 Diffuse midline glioma H3K27-altered, Grade 4 Diffuse hemispheric gliomas H3-G34-mutant, Grade 4 pediatric-type high-grade glioma H3-wildtype and IDH-wildtype, and infant-type hemispheric gliomas. In recent years, we have seen promising advancements in treatment strategies for pediatric high-grade gliomas, including immunotherapy, CAR-T cell therapy, and vaccine approaches, which are currently undergoing clinical trials. These therapies are underscored by the integration of molecular features that further stratify HGG subtypes. Herein, we will discuss the molecular features of pediatric high-grade gliomas and the evolving landscape for treating these challenging tumors.

The Role of Systemic Therapies in the Treatment of Grades 1-4 Gliomas

The primary treatment for gliomas typically involves tumor resection followed by adjuvant radiotherapy, with increasing emphasis on chemotherapy and molecularly targeted drugs. This study aimed to review and summarize the literature on the systemic therapy of malignant gliomas. Chemotherapy may be considered in grades 2 and 3 gliomas, especially when mutations in 1p19q-codeletion are detected. The beneficial impact of adding chemotherapy to radiotherapy (PCV: procarbazine, lomustine, vincristine) has also been demonstrated. In grade 4 glioblastoma multiforme (GBM), wild-type isocitrate dehydrogenase (IDH) status showed the best treatment outcomes with temozolomide (TMZ) in patients with O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation. Prolonging adjuvant TMZ therapy improves treatment outcomes compared to the standard 6-cycle adjuvant therapy. Bevacizumab (BEV) monotherapy can improve progression-free survival and maintain the initial quality of life. Despite advancements in GBM treatment, outcomes remain unsatisfactory, with a median survival of 14-16 months. Further research is still needed regarding the systemic treatment of central nervous system gliomas.

Gastrointestinal Stromal Tumors (GISTs) in Pediatric Patients: A Case Report and Literature Review

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms that primarily affect adults, with pediatric cases constituting only 0.5-2.7% of the total. Pediatric GISTs present unique clinical, genetic, and pathological features that distinguish them from adult cases. This literature review aims to elucidate these differences, emphasizing diagnostic and therapeutic challenges. We discuss the resistance of pediatric GISTs to conventional chemotherapy and highlight the importance of surgical intervention, especially in emergency situations involving intra-abdominal bleeding. The review also explores the molecular characteristics of pediatric GISTs, including rare mutations such as quadruple-negative wild-type GIST with an FGF3 gene gain mutation. To illustrate these points, we conclude with a case from our clinic involving a 15-year-old female with multiple CD117-positive gastric GISTs and a quadruple-negative wild-type genetic profile who required urgent surgical intervention following a failed tumor embolization. This case underscores the critical need for early diagnosis and individualized therapeutic strategies combining oncologic and surgical care to improve outcomes in pediatric GIST patients.

Tricarboxylic Acid Cycle Relationships with Non-Metabolic Processes: A Short Story with DNA Repair and Its Consequences on Cancer Therapy Resistance

Metabolic changes involving the tricarboxylic acid (TCA) cycle have been linked to different non-metabolic cell processes. Among them, apart from cancer and immunity, emerges the DNA damage response (DDR) and specifically DNA damage repair. The oncometabolites succinate, fumarate and 2-hydroxyglutarate (2HG) increase reactive oxygen species levels and create pseudohypoxia conditions that induce DNA damage and/or inhibit DNA repair. Additionally, by influencing DDR modulation, they establish direct relationships with DNA repair on at least four different pathways. The AlkB pathway deals with the removal of N-alkylation DNA and RNA damage that is inhibited by fumarate and 2HG. The MGMT pathway acts in the removal of O-alkylation DNA damage, and it is inhibited by the silencing of the MGMT gene promoter by 2HG and succinate. The other two pathways deal with the repair of double-strand breaks (DSBs) but with opposite effects: the FH pathway, which uses fumarate to help with the repair of this damage, and the chromatin remodeling pathway, in which oncometabolites inhibit its repair by impairing the homologous recombination repair (HRR) system. Since oncometabolites inhibit DNA repair, their removal from tumor cells will not always generate a positive response in cancer therapy. In fact, their presence contributes to longer survival and/or sensitization against tumor therapy in some cancer patients.

Association of M2 macrophages with EMT in glioma identified through combination of multi-omics and machine learning

Background

The incidence of glioma, a prevalent brain malignancy, is increasing, particularly among the elderly population. This study aimed to elucidate the clinical importance of epithelial-mesenchymal transition (EMT) in gliomas and its association with malignancy and prognosis.

Background

The incidence of glioma, particularly among elderly individuals, is on the rise. The malignancy of glioma is determined not only by the oncogenic properties of tumor cells but also by the composition of the tumor microenvironment, which includes immune system macrophages. The prevalence of M2-type macrophages typically fosters tumor progression, yet the underlying mechanism remains elusive. Our study explored the clinical importance of epithelial-mesenchymal transition (EMT) in gliomas and its association with malignancy and prognosis.

Methods

Our study used the gene set variation analysis (GSVA) algorithm to classify different levels of EMT activation based on the transcriptomic and multi-omics data. Machine learning (ML) and single-cell analysis were integrated into our model for comprehensive analysis. A predictive model was constructed and in vitro experiments were performed to validate our findings.

Results

Our study classified 1,641 samples into two clusters based on EMT activation: the EMT-hot group and the EMT-cold group. The EMT-hot group had elevated copy number loss, tumor mutational burden (TMB), and a poorer survival rate. Conversely, the EMT-cold group showed a better survival rate, likely attributed to lower stromal and immune cell scores, as well as decreased expression of human leukocyte antigen-related genes. Driving genes were identified through weighted gene coexpression network analysis (WGCNA) and dimensionality reduction techniques. These genes were then utilized in the construction of a prognostic model using ML and protein-protein interaction (PPI) network analysis. Furthermore, the impact of the core genes identified through single-cell analysis on glioma prognosis was examined.

Conclusion

Our research underscores the efficacy of our model in predicting glioma prognosis and elucidates the connection between the M2 macrophages and EMT. Additionally, core genes such as LY96, C1QB, LGALS1, CSPG5, S100A8, and CHGB were identified as pivotal for mediating the occurrence of EMT induced by M2 macrophages.

Multidisciplinary Management of Isocitrate Dehydrogenase-Mutated Gliomas in a Contemporary Molecularly Defined Era

Mutations in isocitrate dehydrogenase (IDH) genes, an early step in the ontogeny of lower-grade gliomas, induce global epigenetic changes characterized by a hypermethylation phenotype and are critical to tumor classification, treatment decision making, and estimation of patient prognosis. The introduction of IDH inhibitors to block the oncogenic neomorphic function of the mutated protein has resulted in new therapeutic options for these patients. To appreciate the implications of these recent IDH inhibitor results, it is important to juxtapose historical outcomes with chemoradiotherapy. Herein, we rationally evaluate recent IDH inhibitor data within historical precedents to guide contemporary decisions regarding the role of observation, maximal safe resection, adjuvant therapies, and the import of patient and tumor variables. The biological underpinnings of the IDH pathway and the mechanisms, impact, and limitations of IDH inhibitors, the actual magnitude of tumor regression and patient benefit, and emergence of resistance pathways are presented to guide future trial development. Management in the current, molecularly defined era will require careful patient selection and risk factor assessment, followed by an open dialog about the results of studies such as INDIGO, as well as mature data from legacy trials, and a discussion about risk-versus-benefit for the choice of treatment, with multidisciplinary decision making as an absolute prerequisite.

CDKN2A/B Homozygous Deletion Sensitizes IDH-Mutant Glioma to CDK4/6 Inhibition

PURPOSE

Treatment paradigms for isocitrate dehydrogenase (IDH)-mutant gliomas are rapidly evolving. Although typically indolent and responsive to initial treatment, these tumors invariably recur at a higher grade and require salvage treatment. Homozygous deletion of the tumor suppressor gene CDKN2A/B frequently emerges at recurrence in these tumors, driving poor patient outcomes. We investigated the effect of CDK-Rb pathway blockade on IDH-mutant glioma growth in vitro and in vivo using CDK4/6 inhibitors (CDKi).

EXPERIMENTAL DESIGN

Cell viability, proliferation assays, and flow cytometry were used to examine the pharmacologic effect of two distinct CDKi, palbociclib and abemaciclib, in multiple patient-derived IDH-mutant glioma lines. Isogenic models were used to directly investigate the influence of CDKN2A/B status on CDKi sensitivity. Orthotopic xenograft tumor models were used to examine the efficacy and tolerability of CDKi in vivo.

RESULTS

CDKi treatment leads to decreased cell viability and proliferative capacity in patient-derived IDH-mutant glioma lines, coupled with enrichment of cells in the G1 phase. CDKN2A inactivation sensitizes IDH-mutant glioma to CDKi in both endogenous and isogenic models with engineered CDKN2A deletion. CDK4/6 inhibitor administration improves survival in orthotopically implanted IDH-mutant glioma models.

CONCLUSIONS

IDH-mutant gliomas with deletion of CDKN2A/B are sensitized to CDK4/6 inhibitors. These results support the investigation of the use of these agents in a clinical setting.

The 2021 World Health Organization Central Nervous System Tumor Classification: The Spectrum of Diffuse Gliomas

The 2021 edition of the World Health Organization (WHO) classification of central nervous system tumors introduces significant revisions across various tumor types. These updates, encompassing changes in diagnostic techniques, genomic integration, terminology, and grading, are crucial for radiologists, who play a critical role in interpreting brain tumor imaging. Such changes impact the diagnosis and management of nearly all central nervous system tumor categories, including the reclassification, addition, and removal of specific tumor entities. Given their pivotal role in patient care, radiologists must remain conversant with these revisions to effectively contribute to multidisciplinary tumor boards and collaborate with peers in neuro-oncology, neurosurgery, radiation oncology, and neuropathology. This knowledge is essential not only for accurate diagnosis and staging, but also for understanding the molecular and genetic underpinnings of tumors, which can influence treatment decisions and prognostication. This review, therefore, focuses on the most pertinent updates concerning the classification of adult diffuse gliomas, highlighting the aspects most relevant to radiological practice. Emphasis is placed on the implications of new genetic information on tumor behavior and imaging findings, providing necessary tools to stay abreast of advancements in the field. This comprehensive overview aims to enhance the radiologist's ability to integrate new WHO classification criteria into everyday practice, ultimately improving patient outcomes through informed and precise imaging assessments.

Volumetric Response and Survival of Patients With Bulky IDH-Mutated Grade 3 Glioma Managed With FET-FDG-Guided Integrated Boost IMRT

AIMS

Despite relatively favourable outcomes associated with IDH-mutant grade 3 gliomas, many patients present with diffuse non-enhancing disease involving multiple brain regions, prompting concern over both durable disease control and the morbidity associated with large volume radiation therapy. This study audits volumetric response, survival and functional outcomes in this 'large volume' subgroup that undergoes intensity modulated radiation therapy (IMRT).

MATERIALS AND METHODS

From a prospective database of 187 patients with IDH-mutant grade 3 gliomas managed with IMRT between 2008 and 2020, recorded PTV was divided into quartiles. The top quartile, termed the 'large volume cohort' (LVC), was identified. IMRT involved FET-FDG guided integrated boost (59.4/54Gy in 33 fractions). Manual volumetric segmentation of baseline, four months and 13 months post-IMRT tumour were performed for T1, T2 and T1gd MRI sequences. The primary endpoint was volumetric reduction on the T1 and T2 sequences at 13 months and analysed with relapse-free survival (RFS) and overall survival (OS). Morbidity endpoints were assessed at year four post-IMRT and included performance status (ECOG PS) and employment outcomes.

RESULTS

The fourth quartile (LVC) identified 44 patients for whom volumetric analysis was available. The LVC had median PTV of 320cm3 compared to 186.2cm3 for the total group. Anaplastic astrocytoma and oligodendroglioma were equally distributed and tumour sites were frontal (54%), temporal (18%) and parietal lobes (16%). Median follow-up for survivors was 71.5 months. Projected 10-year RFS and OS in LVC was 40% and 62%, compared to 53% and 62% respectively in the overall cohort. The RFS (p = 0.06) and OS (p = 0.65) of the LVC was not significantly different to other PTV quartiles; however the impact of PTV volume reached significance when analysed as a continuous variable (RFS p < 0.01; OS p = 0.02). Median T1 volumes were 26.1cm3, 8.0cm3 and 5.3cm3 at months +0, +3 and +12, respectively. The corresponding T2 volumes were 120.8cm3, 29.1cm3 and 26.3cm3. The median T1 and T2 volume reductions were 77% (q1-3: 57-92%) and 78% (q1-3: 60-85%) at 13 months post-IMRT. Initial T2 volume was associated with worse RFS (p = 0.04) but not OS (p = 0.96). There was no association between median T2 volume reduction and RFS (p = 0.77). For patients assessable at year 4 post-IMRT, no late CTCAE Grade 3/4 toxicity events were recognised. 92% of patients were ECOG PS 0-1, 45% were employed at prior capacity and 28% were working with impairment.

CONCLUSION

Patients with large volume IDH-mutant Grade 3 glioma demonstrated significant tumour reduction post-IMRT, and good long-term outcomes with respect to survival and functional status. Although larger IMRT volumes were associated with poorer RFS, this was also associated with the initial volume of non-enhancing tumour.

High costs, low quality of life, reduced survival, and room for improving treatment: an analysis of burden and unmet needs in glioma

Gliomas are a group of heterogeneous tumors that account for substantial morbidity, mortality, and costs to patients and healthcare systems globally. Survival varies considerably by grade, histology, biomarkers, and genetic alterations such as IDH mutations and MGMT promoter methylation, and treatment, but is poor for some grades and histologies, with many patients with glioblastoma surviving less than a year from diagnosis. The present review provides an introduction to glioma, including its classification, epidemiology, economic and humanistic burden, as well as treatment options. Another focus is on treatment recommendations for IDH-mutant astrocytoma, IDH-mutant oligodendroglioma, and glioblastoma, which were synthesized from recent guidelines. While recommendations are nuanced and reflect the complexity of the disease, maximum safe resection is typically the first step in treatment, followed by radiotherapy and/or chemotherapy using temozolomide or procarbazine, lomustine, and vincristine. Immunotherapies and targeted therapies currently have only a limited role due to disappointing clinical trial results, including in recurrent glioblastoma, for which the nitrosourea lomustine remains the de facto standard of care. The lack of treatment options is compounded by frequently suboptimal clinical practice, in which patients do not receive adequate therapy after resection, including delayed, shortened, or discontinued radiotherapy and chemotherapy courses due to treatment side effects. These unmet needs will require significant efforts to address, including a continued search for novel treatment options, increased awareness of clinical guidelines, improved toxicity management for chemotherapy, and the generation of additional and more robust clinical and health economic evidence.

MGMT promoter methylation in 1p19q-intact gliomas

OBJECTIVE

Standard-of-care for 1p19q-intact anaplastic gliomas is defined by the international randomized phase III CATNON trial, which found an overall survival (OS) benefit for adjuvant temozolomide (TMZ) when added to radiotherapy. Paradoxically, TMZ did not appear to benefit patients with IDH-wildtype gliomas, regardless of MGMT promoter status. The authors concluded that well-powered prospective study on the clinical efficacy of TMZ for patients with IDH-wildtype anaplastic gliomas (meeting criteria for glioblastoma) is warranted. Given that the prognostic and predictive role of MGMT status for grade 2-3 gliomas is unresolved, we determined the effect of MGMT status on OS in patients with 1p19q-intact gliomas in the National Cancer Database (NCDB).

METHODS

We queried the NCDB from 2018 to 2019 for patients with diffuse (grade 2) and anaplastic (grade 3) IDH-wildtype or -mutant astrocytomas who received chemotherapy with follow-up through 2022. The Kaplan-Meier method and Cox proportional hazards regressions models were used to determine the association of MGMT with OS.

RESULTS

We identified 1514 patients who were newly diagnosed with IDH-wildtype (n = 802, 33% methylated) or -mutant astrocytomas (n = 712, 48% methylated) and received chemotherapy during initial management. An unmethylated promoter was associated with poorer survival in patients with IDH-wildtype (3-year OS 34% [95%CI 29-39%] vs. 46% [95%CI 39-54%], p < .001, adjusted HR 1.53 [95%CI 1.24-1.89]) but not IDH-mutant astrocytomas (3-year OS 79% [95%CI 74-84%] vs. 80% [95%CI 75-86%], p =0 .81, HR 1.04 [95%CI 0.73-1.50]).

CONCLUSIONS

This ancillary analysis supports conclusions from the CATNON trial for adjuvant TMZ as standard-of-care for anaplastic astrocytomas (IDH-mutant and 1p19q-intact), irrespective of MGMT status. Determining the optimal strategy for diffuse gliomas that are IDH-wildtype will be particularly important. MGMT promoter methylation should be considered as a stratification factor in future clinical trials for these patients.

Advancements in Glioma Care: Focus on Emerging Neurosurgical Techniques

BACKGROUND

Despite significant advances in understanding the molecular pathways of glioma, translating this knowledge into effective long-term solutions remains a challenge. Indeed, gliomas pose a significant challenge to neurosurgical oncology because of their diverse histopathological features, genetic heterogeneity, and clinical manifestations. Relevant sections: This study focuses on glioma complexity by reviewing recent advances in their management, also considering new classification systems and emerging neurosurgical techniques. To bridge the gap between new neurosurgical approaches and standards of care, the importance of molecular diagnosis and the use of techniques such as laser interstitial thermal therapy (LITT) and focused ultrasound (FUS) are emphasized, exploring how the integration of molecular knowledge with emerging neurosurgical approaches can personalize and improve the treatment of gliomas.

CONCLUSIONS

The choice between LITT and FUS should be tailored to each case, considering factors such as tumor characteristics and patient health. LITT is favored for larger, complex tumors, while FUS is standard for smaller, deep-seated ones. Both techniques are equally effective for small and superficial tumors. Our study provides clear guidance for treating pediatric low-grade gliomas and highlights the crucial roles of LITT and FUS in managing high-grade gliomas in adults. This research sets the stage for improved patient care and future developments in the field of neurosurgery.

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.

Effectiveness and Safety of Different Postoperative Adjuvant Regimens in Patients with Low-Grade Gliomas: A Network Meta-Analysis

OBJECTIVE

This study aimed to investigate the effectiveness and safety of various adjuvant regimens in patients with low-grade gliomas and to further explore the optimal adjuvant treatment for patients with low-grade gliomas and the differences in the efficacy of each treatment regimens in different tumor types.

METHODS

A comprehensive search of the PubMed, Cochrane Library, Ovid, Embase, and Web of Science databases was conducted to screen randomized and nonrandomized controlled trials related to adjuvant therapy in patients with low-grade gliomas. The Cochrane quality assessment method and the Newcastle-Ottawa Scale were used to assess the quality of the included randomized and nonrandomized controlled trials, respectively. The data from previous studies were extracted using Excel and GetData Graph Digitizer 2.26 software, and network meta-analysis was performed using RevMan 5.3 and Stata 16.0 statistical software.

RESULTS

The specific ranking of 5-year progression-free survival (5-year PFS) for each treatment regimen from the best to the worst in patients with low-grade gliomas was surgery (S) combined with procarbazine, lomustine, and vincristine (S + PCV); surgery combined with standard radiotherapy and PCV multidrug chemotherapy (S + RT + PCV); surgery combined with standard radiotherapy and temozolomide monotherapy (S + RT + TMZ); surgery combined with enhanced radiotherapy (S + H-RT); surgery combined with standard radiotherapy (S + RT); surgery combined with TMZ (S + TMZ); and S. The 5-year overall survival (OS) ranking was S + RT + TMZ, S + RT + PCV, surgery combined with enhanced radiotherapy and TMZ monotherapy (S + H-RT + TMZ), S + H-RT, S + RT, and S. The 2-year progression-free survival ranking was S + RT + TMZ, S + PCV, S + RT, S + RT + PCV, S + TMZ, S + H-RT, and S. The 2-year overall survival ranking was S + RT + TMZ, S + H-RT + TMZ, S + RT, S + RT + PCV, S + H-RT, and S. The incidence of adverse events (≥3) was ranked from highest to lowest as follows: S + RT + PCV, S + RT + TMZ, S + PCV, S + H-RT, S + TMZ, and S + RT. In the isocitrate dehydrogenase 1/2 mutation nonchromosome 1p and 19q chromosome whole arm codeletion (IDHmt/noncoder) group, the S + RT + PCV and S + H-RT regimens had better 5-year PFS and 5-year OS. In the isocitrate dehydrogenase 1/2 mutation and chromosome 1p and 19q chromosome whole arm codeletion (IDHmt/coder) group, the 5-year PFS of each treatment regimen ranked from the best to the worst was S + RT + TMZ, S + RT + PCV, S + H-RT, S + RT, S + TMZ, and S. The order of 5-year OS from the best to the worst was S + H-RT, S + RT + TMZ, S + RT + PCV, S + RT, and S. In the isocitrate dehydrogenase 1/2 wild-type (IDHwt) group, the S + H-RT and S + TMZ regimens had better 5-year PFS.

CONCLUSIONS

This study revealed that both the S + RT + TMZ and S + RT + PCV regimens might be effective therapies for treating patients with low-grade gliomas. Among these, the S + RT + TMZ regimen seemed to be safer but might lead to tumor deterioration. In the IDHmt/coder type, the S + RT + TMZ scheme might have a significant advantage. In the IDHmt/noncoder type, the S + RT + PCV scheme might be more dominant, while in the IDHwt type, the S + H-RT and S + TMZ schemes also might be good treatment options.

Targeting cancer metabolic pathways for improving chemotherapy and immunotherapy

Recent discoveries in cancer metabolism have revealed promising metabolic targets to modulate cancer progression, drug response, and anti-cancer immunity. Combination therapy, consisting of metabolic inhibitors and chemotherapeutic or immunotherapeutic agents, offers new opportunities for improved cancer therapy. However, it also presents challenges due to the complexity of cancer metabolic pathways and the metabolic interactions between tumor cells and immune cells. Many studies have been published demonstrating potential synergy between novel inhibitors of metabolism and chemo/immunotherapy, yet our understanding of the underlying mechanisms remains limited. Here, we review the current strategies of altering the metabolic pathways of cancer to improve the anti-cancer effects of chemo/immunotherapy. We also note the need to differentiate the effect of metabolic inhibition on cancer cells and immune cells and highlight nanotechnology as an emerging solution. Improving our understanding of the complexity of the metabolic pathways in different cell populations and the anti-cancer effects of chemo/immunotherapy will aid in the discovery of novel strategies that effectively restrict cancer growth and augment the anti-cancer effects of chemo/immunotherapy.

MGMT promoter methylation in 1p19q-intact gliomas

Objective

Standard-of-care for 1p19q-intact anaplastic gliomas is defined by the international randomized phase III CATNON trial, which found an overall survival (OS) benefit for adjuvant temozolomide (TMZ) when added to radiotherapy. Paradoxically, TMZ did not appear to benefit patients with IDH-wildtype gliomas, regardless of MGMT promoter status. The authors concluded that well-powered prospective study on the clinical efficacy of TMZ for patients with IDH-wildtype anaplastic gliomas (meeting criteria for glioblastoma) is warranted. Given that the prognostic and predictive role of MGMT status for grade 2-3 gliomas is unresolved, we determined the effect of MGMT status on OS in patients with 1p19q-intact gliomas in the National Cancer Database (NCDB).

Methods

We queried the NCDB from 2018-2019 for patients with IDH-wildtype or -mutant astrocytomas who received chemotherapy with follow-up through 2022. The Kaplan-Meier method and Cox proportional hazards regressions models were used to determine the association of MGMT with OS.

Results

We identified 1,514 patients who were newly diagnosed with IDH-wildtype (n = 802, 33% methylated) or - mutant astrocytomas (n = 712, 48% methylated) and received chemotherapy during initial management. An unmethylated promoter was associated with poorer survival in patients with IDH-wildtype (3-year OS 34% [95%CI 29-39%] vs. 46% [95%CI 39-54%], p < .001, adjusted HR 1.53 [95%CI 1.24-1.89]) but not IDH-mutant astrocytomas (3-year OS 79% [95%CI 74-84%] vs. 80% [95%CI 75-86%], p = .81, HR 1.04 [95%CI 0.73-1.50]).

Conclusions

This ancillary analysis supports adjuvant TMZ as standard-of-care for anaplastic astrocytomas (IDH-mutant and 1p19q-intact), irrespective of MGMT status. Determining the optimal strategy for diffuse gliomas that are IDH-wildtype will be particularly important. MGMT promoter methylation should be considered as a stratification factor in future clinical trials for these patients.

Decision system for extent of resection in WHO grade 3 gliomas: a Chinese Glioma Genome Atlas database analysis

BACKGROUND

Extensive surgical resection has been found to be associated with longer survival in patients with gliomas, but the interactive prognostic value of molecular pathology of the surgical resection is unclear. This study evaluated the impact of molecular pathology and clinical characteristics on the surgical benefit in WHO grade 3 IDH-mutant gliomas.

METHODS

Clinical and pathological information of 246 patients with WHO grade 3 IDH-mutant gliomas were collected from the Chinese Glioma Genome Atlas database (2006-2020). The role of the extent of resection on overall survival, stratified by molecular pathology and clinical characteristics, was investigated. We then assessed prognostic factors using a univariate log-rank test and multivariate Cox proportional hazards model in the subgroups.

RESULTS

The extent of resection was an independent prognostic factor in the entire cohort, even when adjusted for molecular pathology. Gross total resection was found to be associated with longer survival in all patients and in the astrocytoma group but not in the oligodendroglioma group. Compared with subtotal resections, gross total resections resulted in a longer survival time for astrocytoma patients aged ≤ 45 years. However, there was no survival benefit from total resection in patients with astrocytoma aged > 45 years.

CONCLUSIONS

Extensive resection benefits only a proportion of patients with WHO grade 3 IDH-mutant gliomas. Younger patients with astrocytomas had survival benefits from extensive resection. In addition to clinical characteristics (especially age), molecular pathology impacted prognosis in patients with gliomas. Our findings provide guiding information to neurosurgeons while planning surgeries.

What Role Does Radiotherapy Play in the Molecular Era for Intrahepatic Cholangiocarcinoma?

ABSTRACT

Intrahepatic cholangiocarcinoma is a rare disease, yet with rising incidence globally. Most patients are not eligible for potentially curative surgical resection, and many patients with unresectable disease die within 12 months of diagnosis, primarily due to liver failure from the primary tumor. Recent prospective and retrospective studies indicate that local control of the primary tumor can be achieved with hypofractionated radiotherapy in patients with unresectable disease, translating into prolonged survival of these patients. During the time that these encouraging reports for radiotherapy have been published, numerous concurrent studies have also shown that intrahepatic cholangiocarcinoma is a molecularly diverse disease with multiple targetable genetic alterations and a complex tumor microenvironment. These biological insights have translated into new drug approvals for subsets of patients. We review the current knowledge about the biology and targeted treatment of intrahepatic cholangiocarcinoma and describe these developments in the context of modern radiotherapy.

Bevacizumab in recurrent WHO grades II-III glioma

Purpose

The management of recurrent WHO grades II-III (rGII-III) glioma is not well established. This study describes the clinical outcomes in patients who received bevacizumab as rescue treatment.

Methods

In this retrospective study, the main inclusion criteria were as follows: adult patients with histologicaly proved rGII-III glioma according 2016 WHO classification treated with bevacizumab from 2011 to 2019, T1 contrast enhancement on MRI. Efficacy was assessed using the high-grade glioma 2017 Response Assessment in Neuro-Oncology criteria. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method.

Results

Eighty-one patients were included (M/F ratio: 1.7, median age at diagnosis: 38 years) among whom 46 (56.8%) had an initial diagnosis of grade II glioma. Previous treatments included at least one surgical intervention, radiotherapy (98.8%), and ≥ 2 chemotherapy lines (64.2%). After bevacizumab initiation, partial response, stable disease, and progressive disease were observed in 27.2%, 22.2%, and 50.6% of patients. The median PFS and OS were 4.9 months (95% confidence interval [CI] 3.7-6.1) and 7.6 months (95% CI 5.5-9.9). Bevacizumab severe toxicity occurred in 12.3%. Twenty-four (29.6%) patients discontinued bevacizumab without radiological progression. Oligodendroglioma and age ≥ 38 years at diagnosis were more frequent in this subgroup (odds ratio = 0.24, 95% CI 0.07-0.84, p = 0.023 and 0.36, 95% CI 0.13-0.99, p = 0.042). Ten of these 24 patients were alive at 12 months and two patients at 8 years after bevacizumab initiation, without any subsequent treatment.

Conclusion

Bevacizumab can be an option for heavily pretreated patients with rGII-III glioma with contrast enhancement. In our study, bevacizumab displayed prolonged activity in a subgroup of patients.

Advances in molecular and imaging biomarkers in lower-grade gliomas

INTRODUCTION

Lower-grade (grade 2-3) gliomas (LGGs) constitutes a group of primary brain tumors with variable clinical behaviors and treatment responses. Recent advancements in molecular biology have redefined their classification, and novel imaging modalities emerged for the noninvasive diagnosis and follow-up.

AREAS COVERED

This review comprehensively analyses the current knowledge on molecular and imaging biomarkers in LGGs. Key molecular alterations, such as IDH mutations and 1p/19q codeletion, are discussed for their prognostic and predictive implications in guiding treatment decisions. Moreover, the authors explore theranostic biomarkers for the potential of tailored therapies. Additionally, they also describe the utility of advanced imaging modalities, including widely available techniques, as dynamic susceptibility contrast perfusion-weighted imaging and less validated, emerging approaches, for the noninvasive LGGs characterization and follow-up.

EXPERT OPINION

The integration of molecular markers enhanced the stratification of LGGs, leading to the new concept of integrated histomolecular classification. While the IDH mutation is an established key prognostic and predictive marker, recent results from IDH inhibitors trials showed its potential value as a theranostic marker. In this setting, advanced MRI techniques such as 2-D-hydroxyglutarate spectroscopy are very promising for the noninvasive diagnosis and monitoring of LGGs. This progress offers exciting prospects for personalized medicine and improved treatment outcomes in LGGs.

Association of MGMT Promoter Methylation With Survival in Low-grade and Anaplastic Gliomas After Alkylating Chemotherapy

Importance

O6-methylguanine-DNA methyltransferase (MGMT [OMIM 156569]) promoter methylation (mMGMT) is predictive of response to alkylating chemotherapy for glioblastomas and is routinely used to guide treatment decisions. However, the utility of MGMT promoter status for low-grade and anaplastic gliomas remains unclear due to molecular heterogeneity and the lack of sufficiently large data sets.

Objective

To evaluate the association of mMGMT for low-grade and anaplastic gliomas with chemotherapy response.

Design, Setting, and Participants

This cohort study aggregated grade II and III primary glioma data from 3 prospective cohort studies with patient data collected from August 13, 1995, to August 3, 2022, comprising 411 patients: MSK-IMPACT, EORTC (European Organization of Research and Treatment of Cancer) 26951, and Columbia University. Statistical analysis was performed from April 2022 to January 2023.

Exposure

MGMT promoter methylation status.

Main Outcomes and Measures

Multivariable Cox proportional hazards regression modeling was used to assess the association of mMGMT status with progression-free survival (PFS) and overall survival (OS) after adjusting for age, sex, molecular class, grade, chemotherapy, and radiotherapy. Subgroups were stratified by treatment status and World Health Organization 2016 molecular classification.

Results

A total of 411 patients (mean [SD] age, 44.1 [14.5] years; 283 men [58%]) met the inclusion criteria, 288 of whom received alkylating chemotherapy. MGMT promoter methylation was observed in 42% of isocitrate dehydrogenase (IDH)-wild-type gliomas (56 of 135), 53% of IDH-mutant and non-codeleted gliomas (79 of 149), and 74% of IDH-mutant and 1p/19q-codeleted gliomas (94 of 127). Among patients who received chemotherapy, mMGMT was associated with improved PFS (median, 68 months [95% CI, 54-132 months] vs 30 months [95% CI, 15-54 months]; log-rank P < .001; adjusted hazard ratio [aHR] for unmethylated MGMT, 1.95 [95% CI, 1.39-2.75]; P < .001) and OS (median, 137 months [95% CI, 104 months to not reached] vs 61 months [95% CI, 47-97 months]; log-rank P < .001; aHR, 1.65 [95% CI, 1.11-2.46]; P = .01). After adjusting for clinical factors, MGMT promoter status was associated with chemotherapy response in IDH-wild-type gliomas (aHR for PFS, 2.15 [95% CI, 1.26-3.66]; P = .005; aHR for OS, 1.69 [95% CI, 0.98-2.91]; P = .06) and IDH-mutant and codeleted gliomas (aHR for PFS, 2.99 [95% CI, 1.44-6.21]; P = .003; aHR for OS, 4.21 [95% CI, 1.25-14.2]; P = .02), but not IDH-mutant and non-codeleted gliomas (aHR for PFS, 1.19 [95% CI, 0.67-2.12]; P = .56; aHR for OS, 1.07 [95% CI, 0.54-2.12]; P = .85). Among patients who did not receive chemotherapy, mMGMT status was not associated with PFS or OS.

Conclusions and Relevance

This study suggests that mMGMT is associated with response to alkylating chemotherapy for low-grade and anaplastic gliomas and may be considered as a stratification factor in future clinical trials of patients with IDH-wild-type and IDH-mutant and codeleted tumors.

Genomic analysis of immunogenic cell death-related subtypes for predicting prognosis and immunotherapy outcomes in glioblastoma multiforme

Immunogenic cell death (ICD), a unique form of cancer cell death, has therapeutic potential in anti-tumour immunotherapy. The aim of this study is to explore the predictive potential of ICD in the prognosis and immunotherapy outcomes of glioblastoma multiforme (GBM). RNA sequencing data and clinical information were downloaded from three databases. Unsupervised consistency clustering analysis was used to identify ICD-related clusters and gene clusters. Additionally, the ICD scores were determined using principal component analysis and the Boruta algorithm via dimensionality reduction techniques. Subsequently, three ICD-related clusters and three gene clusters with different prognoses were identified, with differences in specific tumour immune infiltration-related lymphocytes in these clusters. Moreover, the ICD score was well differentiated among patients with GBM, and the ICD score was considered an independent prognostic factor for patients with GBM. Furthermore, two datasets were used for the external validation of ICD scores as predictors of prognosis and immunotherapy outcomes. The validation analysis suggested that patients with high ICD scores had a worse prognosis. Additionally, a higher proportion of patients with high ICD scores were non-responsive to immunotherapy. Thus, the ICD score has the potential as a biomarker to predict the prognosis and immunotherapy outcomes of patients with GBM.

DNA damage in IDH-mutant gliomas: mechanisms and clinical implications

PURPOSE

Since the discovery of IDH mutations in glioma over a decade ago, significant progress has been made in determining how these mutations affect epigenetic, transcriptomic, and metabolic programs in brain tumor cells. In this article, we summarize current understanding of how IDH mutations influence DNA damage in glioma and discuss clinical implications of these findings.

METHODS

We performed a thorough review of peer-reviewed publications and provide an overview of key mechanisms by which IDH mutations impact response to DNA damage in gliomas, with an emphasis on clinical implications.

RESULTS

The effects of mutant IDH on DNA damage largely fall into four overarching categories: Gene Expression, Sensitivity to Alkylating Agents, Homologous Recombination, and Oxidative Stress. From a mechanistic standpoint, we discuss how mutant IDH and the oncometabolite (R)-2HG affect each of these categories of DNA damage. We also contextualize these mechanisms with respect to ongoing clinical trials. Studies are underway that incorporate current standard-of-care therapies, including radiation and alkylating agents, in addition to novel therapeutic agents that exert genotoxic stress specifically in IDH-mutant gliomas. Lastly, we discuss key unanswered questions and emerging data in this field that have important implications for our understanding of glioma biology and for the development of new brain tumor therapies.

CONCLUSION

Mounting preclinical and clinical data suggest that IDH mutations alter DNA damage sensing and repair pathways through distinct mechanisms. Future studies are needed to deepen our understanding of these processes and provide additional mechanistic insights that can be leveraged for therapeutic benefit.

Radiosensitization of IDH-Mutated Gliomas through ZMYND8 - a Pathway to Improved Outcomes

Isocitrate dehydrogenase 1-mutant (IDH1m) gliomas are recalcitrant tumors for which radiotherapy remains a standard treatment. A recent study identified ZMYND8 as a key mediator of radioresistance for IDH1m gliomas, and pharmacologic targeting of this pathway may heighten radiotherapy-induced tumor response, providing a prospect of improved clinical outcomes. See related article by Carney et al., p. 1763.

Stalled oligodendrocyte differentiation in IDH-mutant gliomas

BACKGROUND

Roughly 50% of adult gliomas harbor isocitrate dehydrogenase (IDH) mutations. According to the 2021 WHO classification guideline, these gliomas are diagnosed as astrocytomas, harboring no 1p19q co-deletion, or oligodendrogliomas, harboring 1p19q co-deletion. Recent studies report that IDH-mutant gliomas share a common developmental hierarchy. However, the neural lineages and differentiation stages in IDH-mutant gliomas remain inadequately characterized.

METHODS

Using bulk transcriptomes and single-cell transcriptomes, we identified genes enriched in IDH-mutant gliomas with or without 1p19q co-deletion, we also assessed the expression pattern of stage-specific signatures and key regulators of oligodendrocyte lineage differentiation. We compared the expression of oligodendrocyte lineage stage-specific markers between quiescent and proliferating malignant single cells. The gene expression profiles were validated using RNAscope analysis and myelin staining and were further substantiated using data of DNA methylation and single-cell ATAC-seq. As a control, we assessed the expression pattern of astrocyte lineage markers.

RESULTS

Genes concordantly enriched in both subtypes of IDH-mutant gliomas are upregulated in oligodendrocyte progenitor cells (OPC). Signatures of early stages of oligodendrocyte lineage and key regulators of OPC specification and maintenance are enriched in all IDH-mutant gliomas. In contrast, signature of myelin-forming oligodendrocytes, myelination regulators, and myelin components are significantly down-regulated or absent in IDH-mutant gliomas. Further, single-cell transcriptomes of IDH-mutant gliomas are similar to OPC and differentiation-committed oligodendrocyte progenitors, but not to myelinating oligodendrocyte. Most IDH-mutant glioma cells are quiescent; quiescent cells and proliferating cells resemble the same differentiation stage of oligodendrocyte lineage. Mirroring the gene expression profiles along the oligodendrocyte lineage, analyses of DNA methylation and single-cell ATAC-seq data demonstrate that genes of myelination regulators and myelin components are hypermethylated and show inaccessible chromatin status, whereas regulators of OPC specification and maintenance are hypomethylated and show open chromatin status. Markers of astrocyte precursors are not enriched in IDH-mutant gliomas.

CONCLUSIONS

Our studies show that despite differences in clinical manifestation and genomic alterations, all IDH-mutant gliomas resemble early stages of oligodendrocyte lineage and are stalled in oligodendrocyte differentiation due to blocked myelination program. These findings provide a framework to accommodate biological features and therapy development for IDH-mutant gliomas.

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.

The Korean Society for Neuro-Oncology (KSNO) Guideline for the Management of Brain Tumor Patients During the Crisis Period: A Consensus Survey About Specific Clinical Scenarios (Version 2023.1)

BACKGROUND

During the coronavirus disease 2019 (COVID-19) pandemic, there was a shortage of medical resources and the need for proper treatment guidelines for brain tumor patients became more pressing. Thus, the Korean Society for Neuro-Oncology (KSNO), a multidisciplinary academic society, has undertaken efforts to develop a guideline that is tailored to the domestic situation and that can be used in similar crisis situations in the future. As part II of the guideline, this consensus survey is to suggest management options in specific clinical scenarios during the crisis period.

METHODS

The KSNO Guideline Working Group consisted of 22 multidisciplinary experts on neuro-oncology in Korea. In order to confirm a consensus reached by the experts, opinions on 5 specific clinical scenarios about the management of brain tumor patients during the crisis period were devised and asked. To build-up the consensus process, Delphi method was employed.

RESULTS

The summary of the final consensus from each scenario are as follows. For patients with newly diagnosed astrocytoma with isocitrate dehydrogenase (IDH)-mutant and oligodendroglioma with IDH-mutant/1p19q codeleted, observation was preferred for patients with low-risk, World Health Organization (WHO) grade 2, and Karnofsky Performance Scale (KPS) ≥60, while adjuvant radiotherapy alone was preferred for patients with high-risk, WHO grade 2, and KPS ≥60. For newly diagnosed patients with glioblastoma, the most preferred adjuvant treatment strategy after surgery was radiotherapy plus temozolomide except for patients aged ≥70 years with KPS of 60 and unmethylated MGMT promoters. In patients with symptomatic brain metastasis, the preferred treatment differed according to the number of brain metastasis and performance status. For patients with newly diagnosed atypical meningioma, adjuvant radiation was deferred in patients with older age, poor performance status, complete resection, or low mitotic count.

CONCLUSION

It is imperative that proper medical care for brain tumor patients be sustained and provided, even during the crisis period. The findings of this consensus survey will be a useful reference in determining appropriate treatment options for brain tumor patients in the specific clinical scenarios covered by the survey during the future crisis.

The Korean Society for Neuro-Oncology (KSNO) Guideline for the Management of Brain Tumor Patients During the Crisis Period: A Consensus Recommendation Using the Delphi Method (Version 2023.1)

BACKGROUND

During the coronavirus disease 2019 (COVID-19) pandemic, the need for appropriate treatment guidelines for patients with brain tumors was indispensable due to the lack and limitations of medical resources. Thus, the Korean Society for Neuro-Oncology (KSNO), a multidisciplinary academic society, has undertaken efforts to develop a guideline that is tailored to the domestic situation and that can be used in similar crisis situations in the future.

METHODS

The KSNO Guideline Working Group was composed of 22 multidisciplinary experts on neuro-oncology in Korea. In order to reach consensus among the experts, the Delphi method was used to build up the final recommendations.

RESULTS

All participating experts completed the series of surveys, and the results of final survey were used to draft the current consensus recommendations. Priority levels of surgery and radiotherapy during crises were proposed using appropriate time window-based criteria for management outcome. The highest priority for surgery is assigned to patients who are life-threatening or have a risk of significant impact on a patient's prognosis unless immediate intervention is given within 24-48 hours. As for the radiotherapy, patients who are at risk of compromising their overall survival or neurological status within 4-6 weeks are assigned to the highest priority. Curative-intent chemotherapy has the highest priority, followed by neoadjuvant/adjuvant and palliative chemotherapy during a crisis period. Telemedicine should be actively considered as a management tool for brain tumor patients during the mass infection crises such as the COVID-19 pandemic.

CONCLUSION

It is crucial that adequate medical care for patients with brain tumors is maintained and provided, even during times of crisis. This guideline will serve as a valuable resource, assisting in the delivery of treatment to brain tumor patients in the event of any future crisis.

Radiomic features from dynamic susceptibility contrast perfusion-weighted imaging improve the three-class prediction of molecular subtypes in patients with adult diffuse gliomas

OBJECTIVES

To investigate whether radiomic features extracted from dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) can improve the prediction of the molecular subtypes of adult diffuse gliomas, and to further develop and validate a multimodal radiomic model by integrating radiomic features from conventional and perfusion MRI.

METHODS

We extracted 1197 radiomic features from each sequence of conventional MRI and DSC-PWI, respectively. The Boruta algorithm was used for feature selection and combination, and a three-class random forest method was applied to construct the models. We also constructed a combined model by integrating radiomic features and clinical metrics. The models' diagnostic performance for discriminating the molecular subtypes (IDH wild type [IDHwt], IDH mutant and 1p/19q-noncodeleted [IDHmut-noncodel], and IDH mutant and 1p/19q-codeleted [IDHmut-codel]) was compared using AUCs in the validation set.

RESULTS

We included 272 patients (training set, n = 166; validation set, n = 106) with grade II-IV gliomas (mean age, 48.7 years; range, 19-77 years). The proportions of the molecular subtypes were 66.2% IDHwt, 15.1% IDHmut-noncodel, and 18.8% IDHmut-codel. Nineteen radiomic features (13 from conventional MRI and 6 from DSC-PWI) were selected to build the multimodal radiomic model. In the validation set, the multimodal radiomic model showed better performance than the conventional radiomic model did in predicting the IDHwt and IDHmut-codel subtypes, which was comparable to the conventional radiomic model in predicting the IDHmut-noncodel subtype. The multimodal radiomic model yielded similar performance as the combined model in predicting the three molecular subtypes.

CONCLUSIONS

Adding DSC-PWI to conventional MRI can improve molecular subtype prediction in patients with diffuse gliomas.

KEY POINTS

• The multimodal radiomic model outperformed conventional MRI when predicting both the IDH wild type and IDH mutant and 1p/19q-codeleted subtypes of gliomas. • The multimodal radiomic model showed comparable performance to the combined model in the prediction of the three molecular subtypes. • Radiomic features from T1-weighted gadolinium contrast-enhanced and relative cerebral blood volume images played an important role in the prediction of molecular subtypes.

Tumor Microenvironment in Gliomas: A Treatment Hurdle or an Opportunity to Grab?

Gliomas are the most frequent central nervous system (CNS) primary tumors. The prognosis and clinical outcomes of these malignancies strongly diverge according to their molecular alterations and range from a few months to decades. The tumor-associated microenvironment involves all cells and connective tissues surrounding tumor cells. The composition of the microenvironment as well as the interactions with associated neoplastic mass, are both variables assuming an increasing interest in these last years. This is mainly because the microenvironment can mediate progression, invasion, dedifferentiation, resistance to treatment, and relapse of primary gliomas. In particular, the tumor microenvironment strongly diverges from isocitrate dehydrogenase (IDH) mutated and wild-type (wt) tumors. Indeed, IDH mutated gliomas often show a lower infiltration of immune cells with reduced angiogenesis as compared to IDH wt gliomas. On the other hand, IDH wt tumors exhibit a strong immune infiltration mediated by several cytokines and chemokines, including CCL2, CCL7, GDNF, CSF-1, GM-CSF, etc. The presence of several factors, including Sox2, Oct4, PD-L1, FAS-L, and TGF β2, also mediate an immune switch toward a regulatory inhibited immune system. Other important interactions are described between IDH wt glioblastoma cells and astrocytes, neurons, and stem cells, while these interactions are less elucidated in IDH-mutated tumors. The possibility of targeting the microenvironment is an intriguing perspective in terms of therapeutic drug development. In this review, we summarized available evidence related to the glioma microenvironment, focusing on differences within different glioma subtypes and on possible therapeutic development.

Adjuvant Chemoradiation Therapy Versus Chemotherapy Alone for Resected Oligodendroglioma: A Surveillance, Epidemiology and End Results (SEER) Analysis

OBJECTIVE

The benefit of postoperative adjuvant therapy for survival of oligodendrocyte glioma remains unclear. In this study, we compared the effect of chemoradiation therapy (CRT) and chemotherapy (CT) alone in patients who underwent resection. We aim to identify which adjuvant therapy provides more survival benefits.

METHODS

We identified patients who underwent oligodendroglioma resection in the Surveillance, Epidemiology and End Results (SEER) database. A multivariate Cox regression analysis was used to evaluate the factors affecting survival rates. We used a propensity matching analysis to minimize selection bias in each group. We performed subgroup analyses based on patients' clinical characteristics.

RESULTS

This study identified 1826 patients who received adjuvant CT (n = 503) or adjuvant CRT (n = 1323). On multivariate analysis, elderly, white and other race, and temporal lobe and parietal lobe tumor site were independent risk factors for improved overall survival (OS). After 1:1 propensity match, we included 501 patients who received CT and 501 with CRT. Patients in the CT group showed improved overall survival rate compared with those who received CRT (median OS: 146 months vs. 111 months). Subgroup analysis showed that improved overall survival in CT group was more significant in patients who were younger or older, male or female, white race, frontal lobe and parietal lobe tumor site, smaller tumor size (≤4 cm), and with gross total resection (GTR) (P < 0.05).

CONCLUSIONS

In patients with resected oligodendroglioma, adjuvant CT is associated with better survival compared to adjuvant CRT. The benefit was more significant in patients who were younger and older, male and female, white race, frontal lobe and parietal lobe tumor site, smaller tumor size (≤4 cm), and with GTR.

Isocitrate dehydrogenase (IDH) mutant gliomas: A Society for Neuro-Oncology (SNO) consensus review on diagnosis, management, and future directions

Isocitrate dehydrogenase (IDH) mutant gliomas are the most common adult, malignant primary brain tumors diagnosed in patients younger than 50, constituting an important cause of morbidity and mortality. In recent years, there has been significant progress in understanding the molecular pathogenesis and biology of these tumors, sparking multiple efforts to improve their diagnosis and treatment. In this consensus review from the Society for Neuro-Oncology (SNO), the current diagnosis and management of IDH-mutant gliomas will be discussed. In addition, novel therapies, such as targeted molecular therapies and immunotherapies, will be reviewed. Current challenges and future directions for research will be discussed.

Signaling pathways in brain tumors and therapeutic interventions

Brain tumors, although rare, contribute to distinct mortality and morbidity at all ages. Although there are few therapeutic options for brain tumors, enhanced biological understanding and unexampled innovations in targeted therapies and immunotherapies have considerably improved patients' prognoses. Nonetheless, the reduced response rates and unavoidable drug resistance of currently available treatment approaches have become a barrier to further improvement in brain tumor (glioma, meningioma, CNS germ cell tumors, and CNS lymphoma) treatment. Previous literature data revealed that several different signaling pathways are dysregulated in brain tumor. Importantly, a better understanding of targeting signaling pathways that influences malignant behavior of brain tumor cells might open the way for the development of novel targeted therapies. Thus, there is an urgent need for a more comprehensive understanding of the pathogenesis of these brain tumors, which might result in greater progress in therapeutic approaches. This paper began with a brief description of the epidemiology, incidence, risk factors, as well as survival of brain tumors. Next, the major signaling pathways underlying these brain tumors' pathogenesis and current progress in therapies, including clinical trials, targeted therapies, immunotherapies, and system therapies, have been systemically reviewed and discussed. Finally, future perspective and challenges of development of novel therapeutic strategies in brain tumor were emphasized.

[Prognosis of overall and disease-free survival in patients with grade 3 astrocytomas (anaplastic astrocytoma, WHO 2016)]

Anaplastic astrocytoma (AA) is a rare intracerebral tumor. Therefore, the number of studies devoted to risk factors of overall and disease-free survival is small. This single-center clinical study is devoted to various factors influencing prognosis of treatment in this group of patients.

MATERIAL AND METHODS

A retrospective study included 389 patients diagnosed with grade 3 astrocytoma. We analyzed dependence of overall and disease-free survival from the following factors: gender, age of onset of disease, tumor extent, surgery, neurological disorders before and after surgery (NANO grading system), Ki67 index, postoperative radio- and chemotherapy (number courses, treatment regimens).

RESULTS

Significant risk factors for overall and disease-free survival were spread and volume of tumor, postoperative neurological aggravation, Ki67 index, IDH mutation, radio- and chemotherapy. Age, frontal lobe tumor and disease manifestation variant were significant only for overall, but not for disease-free survival.

CONCLUSION

This study was based on material of one of the largest clinical series of patients with AA operated on in one center in «molecular» era. Our results are consistent with previous data. Analysis of tumor biology and risk factors for IDH-negative AA without molecular signs of glioblastoma may be perspective.

NCCN Guidelines® Insights: Central Nervous System Cancers, Version 2.2022

The NCCN Guidelines for Central Nervous System (CNS) Cancers focus on management of the following adult CNS cancers: glioma (WHO grade 1, WHO grade 2-3 oligodendroglioma [1p19q codeleted, IDH-mutant], WHO grade 2-4 IDH-mutant astrocytoma, WHO grade 4 glioblastoma), intracranial and spinal ependymomas, medulloblastoma, limited and extensive brain metastases, leptomeningeal metastases, non-AIDS-related primary CNS lymphomas, metastatic spine tumors, meningiomas, and primary spinal cord tumors. The information contained in the algorithms and principles of management sections in the NCCN Guidelines for CNS Cancers are designed to help clinicians navigate through the complex management of patients with CNS tumors. Several important principles guide surgical management and treatment with radiotherapy and systemic therapy for adults with brain tumors. The NCCN CNS Cancers Panel meets at least annually to review comments from reviewers within their institutions, examine relevant new data from publications and abstracts, and reevaluate and update their recommendations. These NCCN Guidelines Insights summarize the panel's most recent recommendations regarding molecular profiling of gliomas.

Benign Glioma

Benign glioma broadly refers to a heterogeneous group of slow-growing glial tumors with low proliferative rates and a more indolent clinical course. These tumors may also be described as "low-grade" glioma (LGG) and are classified as WHO grade I or II lesions according to the Classification of Tumors of the Central Nervous System (CNS) (Louis et al. in Acta Neuropathol 114:97-109, 2007). Advances in molecular genetics have improved understanding of glioma tumorigenesis, leading to the identification of common mutation profiles with significant treatment and prognostic implications. The most recent WHO 2016 classification system has introduced several notable changes in the way that gliomas are diagnosed, with a new emphasis on molecular features as key factors in differentiation (Wesseling and Capper in Neuropathol Appl Neurobiol 44:139-150, 2018). Benign gliomas have a predilection for younger patients and are among the most frequently diagnosed tumors in children and young adults (Ostrom et al. in Neuro Oncol 22:iv1-iv96, 2020). These tumors can be separated into two clinically distinct subgroups. The first group is of focal, well-circumscribed lesions that notably are not associated with an increased risk of malignant transformation. Primarily diagnosed in pediatric patients, these WHO grade I tumors may be cured with surgical resection alone (Sturm et al. in J Clin Oncol 35:2370-2377, 2017). Recurrence rates are low, and the prognosis for these patients is excellent (Ostrom et al. in Neuro Oncol 22:iv1-iv96, 2020). Diffuse gliomas are WHO grade II lesions with a more infiltrative pattern of growth and high propensity for recurrence. These tumors are primarily diagnosed in young adult patients, and classically present with seizures (Pallud et al. Brain 137:449-462, 2014). The term "benign" is a misnomer in many cases, as the natural history of these tumors is with malignant transformation and recurrence as grade III or grade IV tumors (Jooma et al. in J Neurosurg 14:356-363, 2019). For all LGG, surgery with maximal safe resection is the treatment of choice for both primary and recurrent tumors. The goal of surgery should be for gross total resection (GTR), as complete tumor removal is associated with higher rates of tumor control and seizure freedom. Chemotherapy and radiation therapy (RT), while not typically a component of first-line treatment in most cases, may be employed as adjunctive therapy in high-risk or recurrent tumors and in some select cases. The prognosis of benign gliomas varies widely; non-infiltrative tumor subtypes generally have an excellent prognosis, while diffusely infiltrative tumors, although slow-growing, are eventually fatal (Sturm et al. in J Clin Oncol 35:2370-2377, 2017). This chapter reviews the shared and unique individual features of the benign glioma including diffuse glioma, pilocytic astrocytoma and pilomyxoid astrocytoma (PMA), subependymal giant cell astrocytoma (SEGA), pleomorphic xanthoastrocytoma (PXA), subependymoma (SE), angiocentric glioma (AG), and chordoid glioma (CG). Also discussed is ganglioglioma (GG), a mixed neuronal-glial tumor that represents a notable diagnosis in the differential for other LGG (Wesseling and Capper 2018). Ependymomas of the brain and spinal cord, including major histologic subtypes, are discussed in other chapters.

Proton radiotherapy in the treatment of IDH-mutant diffuse gliomas: an early experience from shanghai proton and heavy ion center

PURPOSE

According to the presence or absence of isocitrate dehydrogenase (IDH) mutation, the 2021 WHO classification system bisected diffuse gliomas into IDH-mutant tumors and IDH-wildtype tumors. This study was aimed to evaluate the outcomes of proton radiotherapy treating IDH-mutant diffuse gliomas.

PATIENTS AND METHODS

Between May 2015 and May 2022, a total of 52 consecutive patients with IDH-mutant diffuse gliomas were treated at Shanghai Proton and Heavy Ion Center. Tumor histologies were 33 cases of astrocytoma and 19 cases of oligodendroglioma. Tumor classified by WHO grade 2, 3 and 4 were 22, 25, and 5 cases, respectively. All 22 patients with WHO grade 2 tumors and one patient with brain stem WHO grade 4 tumor were irradiated with 54GyE. The other 29 patients with WHO grade 3 and 4 tumors were irradiated with 60GyE. Temozolomide was recommended to all patients, and was eventually conducted in 50 patients.

RESULTS

The median follow-up time was 21.7 months. The 12/24-month progression-free survival (PFS) and overall survival (OS) rates for the entire cohort were 97.6%/78.4% and 100%/91.0% group. Examined by both univariate and multivariate analysis, WHO grade of tumor were of the most significant impact for both PFS and OS. No severe acute toxicity (grade 3 or above) was found. In terms of late toxicity, grade 3 radio-necrosis was developed in one case of oligodendroglioma, WHO grade 3.

CONCLUSION

Proton radiotherapy produced a favorable outcome with acceptable adverse-effects in patients with IDH-mutant diffuse gliomas.

Construction of a machine learning-based artificial neural network for discriminating PANoptosis related subgroups to predict prognosis in low-grade gliomas

The poor prognosis of gliomas necessitates the search for biomarkers for predicting clinical outcomes. Recent studies have shown that PANoptosis play an important role in tumor progression. However, the role of PANoptosis in in gliomas has not been fully clarified.Low-grade gliomas (LGGs) from TCGA and CGGA database were classified into two PANoptosis patterns based on the expression of PANoptosis related genes (PRGs) using consensus clustering method, followed which the differentially expressed genes (DEGs) between two PANoptosis patterns were defined as PANoptosis related gene signature. Subsequently, LGGs were separated into two PANoptosis related gene clusters with distinct prognosis based on PANoptosis related gene signature. Univariate and multivariate cox regression analysis confirmed the prognostic values of PANoptosis related gene cluster, based on which a nomogram model was constructed to predict the prognosis in LGGs. ESTIMATE algorithm, MCP counter and CIBERSORT algorithm were utilized to explore the distinct characteristics of tumor microenvironment (TME) between two PANoptosis related gene clusters. Furthermore, an artificial neural network (ANN) model based on machine learning methods was developed to discriminate distinct PANoptosis related gene clusters. Two external datasets were used to verify the performance of the ANN model. The Human Protein Atlas website and western blotting were utilized to confirm the expression of the featured genes involved the ANN model. We developed a machine learning based ANN model for discriminating PANoptosis related subgroups with drawing implications in predicting prognosis in gliomas.

Changes in clinical management of diffuse IDH-mutated lower-grade gliomas: patterns of care in a 15-year period

BACKGROUND

Isocitrate dehydrogenase (IDH) mutated diffuse lower-grade gliomas (dLGG) are infiltrating brain tumors and increasing evidence is in favor of early multimodal treatment. In a Scandinavian population-based setting, we wanted to study treatment patterns over the last 15 years, focusing on the short-term postoperative course to better understand the potential negative consequences of treatment.

METHODS

Patients ≥ 18 years with primary IDH-mutated dLGG grade 2 and 3, operated between January 2007-June 2021 were identified. Patients were divided into subgroups (2007-2011, 2012-2016, and 2017-2021) and comparisons regarding tumor- and disease characteristics, treatment, and postoperative outcome were performed.

RESULTS

We identified 202 patients (n = 61, 2007-2011; n = 72, 2012-2016; n = 69, 2017-2021), where of 193 underwent resection without change in proportion of resections over time. More patients underwent complete resections in recent times (6.1%; 15.7%; 26.1%, respectively; p = 0.016). Forty-two patients had any neurological deficit postoperatively (14.8%; 23.6%; 23.2%; p = 0.379), mostly minor and transient. Differences in oncological therapy were seen between the investigated subgroups. Early radiotherapy alone (32.8%; 7%; 2.9%; p < 0.001), concomitant chemoradiotherapy (23%; 37.5%; 17.4%; p = 0.022), sequential chemoradiotherapy (0%; 18%; 49.3%; p < 0.001), and no adjuvant treatment (42.6%; 23.6%; 18.8%; p = 0.009) shifted during the studied period. Increasingly more patients received proton radiotherapy compared to photon radiotherapy during the later time periods (p < 0.001).

CONCLUSION

Complete resections were performed more often in later time periods without an apparent increase in surgical morbidity. Early adjuvant oncological treatment shifted towards providing chemotherapy and combined chemoradiotherapy more often in later time periods. Protons replaced photons as the radiation modality of choice.

Establishing a glutamine metabolism-based model for predicting the prognosis of low-grade glioma

Background: The natural history of patients with low-grade glioma (LGG) varies widely, but most patients eventually deteriorate, leading to poor prognostic outcomes. We aim to develop biological models that can accurately predict the outcome of LGG prognosis. Methods: Prognostic genes for glutamine metabolism were searched by univariate Cox regression, and molecular typing was constructed. Functional enrichment analysis was done to evaluate potential prognostic-related pathways by analyzing differential genes in different subtypes. Enrichment scores of specific gene sets in different subtypes were measured by gene set enrichment analysis. Different immune infiltration levels among subtypes were calculated using algorithms such as CIBERSORT and ESTIMATE. Gene expression levels of prognostic-related gene signatures of glutamine metabolism phenotypes were used to construct a RiskScore model. Receiver operating characteristic curve, decision curve and calibration curve analyses were used to evaluate the reliability and validity of the risk model. The decision tree model was used to determine the best predictor variable ultimately. Results: We found that C1 had the worst prognosis and the highest level of immune infiltration, among which the highest macrophage infiltration can be found in the M2 stage. Moreover, most of the pathways associated with tumor development, such as MYC_TARGETS_V1 and EPITHELIAL_MESENCHYMAL_TRANSITION, were significantly enriched in C1. The wild-type IDH and MGMT hypermethylation were the most abundant in C1. A five-gene risk model related to glutamine metabolism phenotype was established with good performance in both training and validation datasets. The final decision tree demonstrated the RiskScore model as the most significant predictor of prognostic outcomes in individuals with LGG. Conclusion: The RiskScore model related to glutamine metabolism can be an exceedingly accurate predictor for LGG patients, providing valuable suggestions for personalized treatment.