CODEL: phase III study of RT, RT + TMZ, or TMZ for newly diagnosed 1p/19q codeleted oligodendroglioma. Analysis from the initial study design

Targeted reprogramming of tumor-associated macrophages for overcoming glioblastoma resistance to chemotherapy and immunotherapy

The resistance of glioblastoma multiforme (GBM) to standard chemotherapy is primarily attributed to the existence of tumor-associated macrophages (TAMs) in the GBM microenvironment, particularly the anti-inflammatory M2 phenotype. Targeted modulation of M2-TAMs is emerging as a promising strategy to enhance chemotherapeutic efficacy. However, combination TAM-targeted therapy with chemotherapy faces substantial challenges, notably in terms of delivery efficiency and targeting specificity. In this study, we designed a pH-responsive hierarchical brain-targeting micelleplex loaded with temozolomide (TMZ) and resiquimod (R848) for combination chemo-immunotherapy against GBM. This delivery system, termed PCPA&PPM@TR, features a primary Angiopep-2 decoration on the outer layer via a pH-cleavable linker and a secondary mannose analogue (MAN) on the middle layer. This pH-responsive hierarchical targeting strategy enables effective BBB permeability while simultaneous GBM- and TAMs-targeting delivery. GBM-targeted delivery of TMZ induces alkylation and triggers an anti-GBM immune response. Concurrently, TAM-targeted delivery of R848 reprograms their phenotype from M2 to pro-inflammatory M1, thereby diminishing GBM resistance to TMZ and amplifying the immune response. In vivo studies demonstrated that targeted modulation of TAMs using PCPA&PPM@TR significantly enhanced anti-GBM efficacy. In summary, this study proposes a promising brain-targeting delivery system for the targeted modulation of TAMs to combat GBM.

Dosimetric evaluation and treatment planning considerations for GammaTile permanent brain implants - a pilot, institutional experience

PURPOSE

GammaTile® (GT) is a brachytherapy platform that received Federal Drug Administration (FDA) approval as brain tumor therapy in late 2018. Here, we reviewed our institutional experience with GT as treatment for recurrent glioblastomas and characterized dosimetric parameter and associated clinical outcome.

METHODS AND MATERIALS

A total of 20 consecutive patients with 21 (n = 21) diagnosis of recurrent glioblastoma underwent resection followed by intraoperative GT implant between 01/2019 and 12/2020. Data on gross tumor volume (GTV), number of GT units implanted, dose coverage for the high-risk clinical target volume (HR-CTV), measured by D90 or dose received by 90% of the HR-CTV, dose to organs at risk, and six months local control were collected.

RESULTS

The median D90 to HR-CTV was 56.0 Gy (31.7-98.7 Gy). The brainstem, optic chiasm, ipsilateral optic nerve, and ipsilateral hippocampus median Dmax were 11.2, 5.4, 6.4, and 10.0 Gy, respectively. None of the patients in this study cohort suffered from radiation necrosis or adverse events attributable to the GT. Correlation was found between pre-op GTV, the volume of the resection cavity, and the number of GT units implanted. Of the resection cavities, 7/21 (33%) of the cavity experienced shrinkage, 3/21 (14%) remained stable, and 11/21 (52%) of the cavities expanded on the 3-months post-resection/GT implant MRIs. D90 to HR-CTV was found to be associated with local recurrence at 6-month post GT implant, suggesting a dose response relationship (p = 0.026). The median local recurrence-free survival was 366.5 days (64-1,098 days), and a trend towards improved local recurrence-free survival was seen in patients with D90 to HR-CTV ≥ 56 Gy (p = 0.048).

CONCLUSIONS

Our pilot, institutional experience provides clinical outcome, dosimetric considerations, and offer technical guidance in the clinical implementation of GT brachytherapy.

A systematic review and meta-analysis informing the role of adjuvant radiotherapy (RT) in Grade 2 and 3 oligodendroglioma

BACKGROUND AND PURPOSE

Evidence and clinical guidelines support the use of adjuvant RT in high-risk low-grade gliomas. However, patients with oligodendroglioma have a more indolent disease course and delaying or avoiding RT is often considered to reduce treatment-related toxicities. As the optimal adjuvant management for oligodendroglioma is unclear, we aimed to assess the effect of adjuvant RT on overall survival (OS) and progression-free survival (PFS).

METHODS

MEDLINE, EMBASE, CENTRAL and CINAHL were searched from January 1990 to February 2023 for studies comparing adjuvant RT versus no adjuvant RT for patients with oligodendroglioma.

RESULTS

This review found 17 eligible studies including 14 comparative retrospective studies and 3 randomized controlled trials. Using random-effects model, the results suggested that adjuvant RT improved OS by 28 % (HR 0.72, 95 % CI (0.56-0.93), I2 = 86 %), and PFS by 48 % (HR 0.52, (95 % CI 0.40-0.66), I2 = 48 %) compared to patients without adjuvant RT. Subgroup analysis showed that upfront adjuvant RT improved OS and PFS compared to salvage RT. There were no significant differences in OS and PFS between adjuvant RT versus adjuvant chemotherapy. There was improvement in PFS but not OS for adjuvant chemoradiotherapy versus adjuvant chemotherapy alone. Adjuvant RT improved OS in WHO Grade 3 but not WHO Grade 2 oligodendroglioma.

CONCLUSION

Overall, adjuvant RT improved OS and PFS in patients with oligodendroglioma. In patients with low-risk features (e.g. Grade 2, gross total resection), alternative approaches and individualization of management such as adjuvant chemotherapy alone may be reasonable considering the lack of survival benefit. Future efforts should prospectively investigate these treatment regimens on molecularly-classified oligodendroglioma patients (defined by presence of IDH mutation and 1p/19q co-deletion), balancing between maximizing survival outcomes and reducing RT-related toxicities.

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.

Treatment of IDH-mutant glioma in the INDIGO era

Gliomas are the most common primary brain tumor and are uniformly lethal. Despite significant advancements in understanding the genetic landscape of gliomas, standard-of-care has remained largely unchanged. Subsets of gliomas are defined by gain-of-function mutations in the metabolic genes encoding isocitrate dehydrogenase (IDH). Efforts to exploit mutant IDH activity and/or directly inhibit it with mutant IDH inhibitors have been the focus of over a decade of research. The recently published INDIGO trial, demonstrating the benefit of the mutant IDH inhibitor vorasidenib in patients with low-grade IDH-mutant gliomas, introduces a new era of precision medicine in brain tumors that is poised to change standard-of-care. In this review, we highlight and contextualize the results of the INDIGO trial and introduce key questions whose answers will guide how mutant IDH inhibitors may be used in the clinic. We discuss possible combination therapies with mutant IDH inhibition and future directions for clinical and translational research.

Clinical Course after Carmustine Wafer Implantation for Newly Diagnosed Adult-type Diffuse Gliomas; A controlled propensity matched analysis of a single center cohort

PURPOSE

It remains unclear whether combining carmustine wafer (CW) implantation with the standard treatment for adult-type diffuse gliomas is safe and has a prognostic impact. This study aimed to investigate the prognostic value and safety of CW implantation.

METHODS

Adult patients with IDH-wild-type and -mutant gliomas, grades 3-4 treated with surgical resection, radiotherapy, and temozolomide chemotherapy between 2013 and 2023 were surveyed. CWs were implanted except in cases of intraoperative wide ventricle opening or marked preoperative brain swelling. For survival analyses, a case-matched dataset based on propensity score matching (PSM), including multiple factors (patient background, diagnosis, and extent of resection) was generated. Progression-free survival (PFS), overall survival (OS), and frequency of complications of CW implantation (brain edema, infection, and cerebrospinal fluid leakage) were compared between the CW and non-use groups.

RESULTS

In total, 127 patients (75 in the CW use group and 52 in the non-use group) were enrolled. Regardless of stratification, no significant differences in PFS and OS were observed between the CW use and non-use groups. The frequency of postoperative brain edema was significantly higher in the CW use group than in the non-use group. An adjusted dataset containing 41 patients in the CW use and nonuse groups was generated. Even after PSM, CW implantation had no prognostic effect.

CONCLUSIONS

CW implantation with standard treatment demonstrated little beneficial effect for the present strategy of CW use.

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.

Rare dual-genotype IDH mutant glioma: Review of previously reported cases and two new cases of true "oligoastrocytoma"

In 2016, the World Health Organization (WHO) eliminated "oligoastrocytoma" from the classification of central nervous system (CNS) tumors, in favor of an integrated histologic and molecular diagnosis. Consistent with the 2016 classification, in the 2021 classification, oligodendrogliomas are defined by mutations in isocitrate dehydrogenase (IDH) with concurrent 1p19q codeletion, while astrocytomas are IDH mutant tumors, usually with ATRX loss. In 2007, a 24-year-old man presented with a brain tumor histologically described as astrocytoma, but with molecular studies consistent with an oligodendroglioma, IDH mutant and 1p19q-codeleted. Years later, at resection, pathology revealed an astrocytoma, with variable ATRX expression and mutations of IDH, ATRX, TP53, and TERT by DNA sequencing. Fluorescence in situ hybridization studies confirmed 1p19q codeletion in sections of the tumor shown to histologically retain ATRX expression. Separately, in 2017, a 36-year-old woman presented with a frontal brain tumor with pathology consistent with an oligodendroglioma, IDH mutant and 1p19q-codeleted. Two years later, pathology revealed an astrocytoma, IDH1 mutant, with ATRX loss. These two cases likely represent the rare occurrence of dual-genotype IDH mutant infiltrating glioma. Nine cases of dual-genotype IDH mutant glioma were previously reported in the literature. We present two cases in which this distinct molecular phenotype is present in a tumor in the same location with surgeries at two points in time, both with 1p19q codeletion and ATRX loss at the time of resection. Whether this represents a true "collision tumor" or genetic switching over time is not known, but the co-occurrence of these hybrid mutations supports a diagnosis of dual-genotype IDH mutant glioma.

Rise of oligodendroglioma hypermutator phenotype from a subclone harboring TP53 mutation after TMZ treatment

Oligodendrogliomas characterized and defined by 1p/19q co-deletion are slowly growing tumors showing better prognosis than astrocytomas. TP53 mutation is rare in oligodendrogliomas while the vast majority of astrocytomas harbor the mutation, making TP53 mutation mutually exclusive with 1p/19q codeletion in lower grade gliomas virtually. We report a case of 51-year-old woman with a left fronto-temporal oligodendroglioma that contained a small portion with a TP53 mutation, R248Q, at the initial surgery. On a first, slow-growing recurrence 29 months after radiation and nitrosourea-based chemotherapy, the patient underwent TMZ chemotherapy. The recurrent tumor responded well to TMZ but developed a rapid progression after 6 cycles as a malignant hypermutator tumor with a MSH6 mutation. Most of the recurrent tumor lacked typical oligodendroglioma morphology that was observed in the primary tumor, while it retained the IDH1 mutation and 1p/19q co-deletion. The identical TP53 mutation observed in the small portion of the primary tumor was universal in the recurrence. This case embodied the theoretically understandable clonal expansion of the TP53 mutation with additional mismatch repair gene dysfunction leading to hypermutator phenotype. It thus indicated that TP53 mutation in oligodendroglioma, although not common, may play a critical role in the development of hypermutator after TMZ treatment.

Post-ictal changes presenting as late pseudoprogression on MRI and PET in a patient with diffuse glioma: Case report and brief literature review

Following completion of adjuvant radiation and chemotherapy imaging surveillance forms a major role in the management of diffuse gliomas. The primary role of imaging is to detect recurrences earlier than clinical symptomatology. Magnetic resonance imaging (MRI) is considered the gold standard in follow-up protocols owing to better soft tissue delineation and multiparametric nature. True recurrence can often mimic treatment-related changes, it is of paramount importance to differentiate between the two entities as the clinical course is divergent. Addition of functional sequences like perfusion, spectroscopy and metabolic imaging can provide further details into the microenvironment. In equivocal cases, a follow-up short interval imaging might be obtained to settle the diagnostic dilemma. Here, we present a patient with diagnosis of recurrent oligodendroglioma treated with adjuvant chemoradiation, presenting with seizures five years post-completion of chemotherapy for recurrence. On MRI, subtle new onset gyral thickening of the left frontal region with mild increase in perfusion and patchy areas of raised choline. FET-PET (fluoro-ethyltyrosine) showed an increased tumour-to-white matter (T/Wm) ratio favouring tumour recurrence. Based on discussion in a multi-disciplinary joint clinic, short interval follow-up MRI was undertaken at two months showing decrease in gyral thickening and resolution of enhancing areas in left frontal lobe. Repeat imaging one year later demonstrated stable disease status without further new imaging findings. Given the changes resolving completely without any anti-tumoral intervention, we conclude this to be peri-ictal pseudoprogression, being the second such case described in India.

Oligodendroglioma, IDH-mutant and 1p/19q-codeleted-prognostic factors, standard of care and chemotherapy, and future perspectives with neoadjuvant strategy

Oligodendroglioma, IDH-mutant and 1p/19q-codeleted is known for their relative chemosensitivity and indolent clinical course among diffuse gliomas of adult type. Based on the data from phase 3 clinical trials, the standard of post-surgical care for those tumors is considered to be initial chemoradiotherapy regardless of histopathological grade, particularly with PCV. However, partly due to its renewed definition in late years, prognostic factors in patients with those tumors are not well established. Moreover, the survival rate declines over 15 years, with only a 37% OS rate at 20 years for grade 3 tumors, even with the current standard of care. Given that most of this disease occurs in young or middle-aged adults, further improvements in treatment and management are necessary. Here, we discuss prognostic factors, standard of care and chemotherapy, and future perspectives with neoadjuvant strategy in those tumors.

Updates on management of gliomas in the molecular age

Gliomas are primary brain tumors derived from glial cells of the central nervous system, afflicting both adults and children with distinct characteristics and therapeutic challenges. Recent developments have ushered in novel clinical and molecular prognostic factors, reshaping treatment paradigms based on classification and grading, determined by histological attributes and cellular lineage. This review article delves into the diverse treatment modalities tailored to the specific grades and molecular classifications of gliomas that are currently being discussed and used clinically in the year 2023. For adults, the therapeutic triad typically consists of surgical resection, chemotherapy, and radiotherapy. In contrast, pediatric gliomas, due to their diversity, require a more tailored approach. Although complete tumor excision can be curative based on the location and grade of the glioma, certain non-resectable cases demand a chemotherapy approach usually involving, vincristine and carboplatin. Additionally, if surgery or chemotherapy strategies are unsuccessful, Vinblastine can be used. Despite recent advancements in treatment methodologies, there remains a need of exploration in the literature, particularly concerning the efficacy of treatment regimens for isocitrate dehydrogenase type mutant astrocytomas and fine-tuned therapeutic approaches tailored for pediatric cohorts. This review article explores into the therapeutic modalities employed for both adult and pediatric gliomas in the context of their molecular classification.

Impact of intensity-modulated proton therapy in reducing radiation-induced lymphopenia in glioma patients

Background

Current standard management in adult grades 2-4 gliomas includes maximal safe resection followed by adjuvant radiotherapy (RT) and chemotherapy. Radiation-induced lymphopenia (RIL) has been shown to possibly affect treatment outcomes adversely. Proton beam therapy (PBT) may reduce the volume of the normal brain receiving moderate radiation doses, and consequently RIL. Our aim was to evaluate the incidence and severity of RIL during proton beam therapy (PBT).

Methods

We identified patients with grades 2-4 glioma treated with PBT at our center between January 2019 and December 2021. We evaluated the incidence and severity of RIL from weekly complete blood count (CBC) data collected during PBT and compared it to the patients who were treated with photon-based RT (XRT) at our center during the same time.

Results

The incidence of any degree of lymphopenia (48% in PBT, vs. 81.2% in XRT, P value = .001) and severe lymphopenia (8% in PBT, vs. 24.6% in XRT, P value = .093) were both significantly lesser in patients who received PBT. Severe RIL in patients receiving PBT was seen in only CNS WHO Gr-4 tumors. Mean whole brain V20GyE and V25GyE inversely correlated to nadir ALC and were both significantly lower with PBT. Patients with lymphopenia during PBT showed a trend toward poorer progression-free survival (P = .053) compared to those with maintained lymphocyte counts.

Conclusions

Proton therapy seems to have a superior sparing of normal brain to moderate dose radiation than photon-based RT and reduces the incidence of lymphopenia. Glioma patients with lymphopenia possibly have worse outcomes than the ones with maintained lymphocyte counts.

Neuro-oncology Treatment Strategies for Primary Glial Tumors

Primary brain tumors underwent reclassification in the 2021 World Health Organization update, relying on molecular findings (especially isocitrate dehydrogenase mutations and chromosomal changes in 1p, 19q, gain of chromosome 7 and loss of chromosome 10). Newer entities have also been described including histone 3 mutant midline gliomas. These updated pathologic classifications improve prognostication and reliable diagnosis, but may confuse interpretation of prior clinical trials and require reclassification of patients diagnosed in the past. For patients over seventy, multiple studies have now confirmed the utility of shorter courses of radiation, and the risk of post-operative delirium. Ongoing studies are comparing proton to photon radiation. Long term follow up of prior clinical trials have confirmed the roles and length of chemotherapy (mainly temozolomide) in different tumors, as well as the wearable novottf device. New oral isocitrate dehydrogenase inhibitors have also shown efficacy in clinical trials.

Adult-type Diffuse Gliomas

OBJECTIVE

This article highlights key aspects of the diagnosis and management of adult-type diffuse gliomas, including glioblastomas and IDH-mutant gliomas relevant to the daily practice of the general neurologist.

LATEST DEVELOPMENTS

The advances in molecular characterization of gliomas have translated into more accurate prognostication and tumor classification. Gliomas previously categorized by histological appearance solely as astrocytomas or oligodendrogliomas are now also defined by molecular features. Furthermore, ongoing clinical trials have incorporated these advances to tailor more effective treatments for specific glioma subtypes.

ESSENTIAL POINTS

Despite recent insights into the molecular aspects of gliomas, these tumors remain incurable. Care for patients with these complex tumors requires a multidisciplinary team in which the general neurologist has an important role. Efforts focus on translating the latest data into more effective therapies that can prolong survival.

MGMT Promoter Methylation Predicts Overall Survival after Chemotherapy for 1p/19q-Codeleted Gliomas

PURPOSE

While MGMT promoter methylation (mMGMT) is predictive of response to alkylating chemotherapy and guides treatment decisions in glioblastoma, its role in grade 2 and 3 glioma remains unclear. Recent data suggest that mMGMT is prognostic of progression-free survival in 1p/19q-codeleted oligodendrogliomas, but an effect on overall survival (OS) has not been demonstrated.

EXPERIMENTAL DESIGN

We identified patients with newly diagnosed 1p/19q-codeleted gliomas and known MGMT promoter status in the National Cancer Database from 2010 to 2019. Multivariable Cox proportional hazards regression modeling was used to assess the effect of mMGMT on OS after adjusting for age, sex, race, comorbidity, grade, extent of resection, chemotherapy, and radiotherapy.

RESULTS

We identified 1,297 eligible patients, 938 (72.3%) of whom received chemotherapy in their initial course of treatment. The MGMT promoter was methylated in 1,009 (77.8%) patients. Unmethylated MGMT (uMGMT) was associated with worse survival compared with mMGMT [70% {95% confidence interval (CI), 64%-77%} vs. 81% (95% CI, 78%-85%); P < 0.001; adjusted HR (aHR), 2.35 (95% CI, 1.77-3.14)]. uMGMT was associated with worse survival in patients who received chemotherapy [63% (95% CI, 55-73%) vs. 80% (95% CI, 76%-84%); P < 0.001; aHR, 2.61 (95% CI, 1.89-3.60)] but not in patients who did not receive chemotherapy [P = 0.38; HR, 1.31 (95% CI, 0.71-2.42)]. Similar results were observed regardless of World Health Organization grade and after single- or multiagent chemotherapy.

CONCLUSIONS

Our study demonstrates an association between mMGMT and OS in 1p/19q-codeleted gliomas. MGMT promoter status should be considered as a stratification factor in future clinical trials of 1p/19q-codeleted gliomas that use OS as an endpoint.

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.

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.

Therapies for IDH-Mutant Gliomas

PURPOSE OF REVIEW

Isocitrate dehydrogenase (IDH) mutant gliomas are a distinct type of primary brain tumors with unique characteristics, behavior, and disease outcomes. This article provides a review of standard of care treatment options and innovative, therapeutic approaches that are currently under investigation for these tumors.

RECENT FINDINGS

Extensive pre-clinical data and a variety of clinical studies support targeting IDH mutations in glioma using different mechanisms, which include direct inhibition and immunotherapies that target metabolic and epigenomic vulnerabilities caused by these mutations. IDH mutations have been recognized as an oncogenic driver in gliomas for more than a decade and as a positive prognostic factor influencing the research for new therapeutic methods including IDH inhibitors, DNA repair inhibitors, and immunotherapy.

National-level overall survival patterns for molecularly-defined diffuse glioma types in the United States

BACKGROUND

Molecularly-defined diffuse glioma types-including IDH-wildtype glioblastoma, IDH-mutant astrocytoma, IDH-mutant 1p/19q-codeleted oligodendroglioma, and H3 K27M-mutant diffuse midline glioma-were incorporated into U.S. cancer registry reporting for individuals with brain tumors beginning in 2018. We leveraged these new data to estimate the national-level overall survival (OS) patterns associated with glioma integrated diagnoses.

METHODS

Individuals diagnosed with diffuse gliomas in 2018 and had brain molecular marker data were identified within the U.S. National Cancer Database. OS was estimated using Kaplan-Meier methods and stratified by WHO CNS grade, age, sex, tumor size, treatment, extent of resection, and MGMT promoter methylation. Additionally, the effects of WHO CNS grade were examined among individuals with IDH-wildtype astrocytic gliomas.

RESULTS

8651 individuals were identified. One-year OS was 53.7% for WHO grade 4 IDH-wildtype glioblastomas; 98.0%, 92.4%, and 76.3% for WHO grade 2, 3, and 4 IDH-mutant astrocytomas, respectively; 97.9% and 94.4% for WHO grade 2 and 3 IDH-mutant 1p/19q-codeleted oligodendrogliomas, respectively; and 55.9% for H3 K27M-mutant diffuse midline gliomas. Among IDH-wildtype glioblastomas, median OS was 17.1 months and 12.4 months for methylated and unmethylated MGMT promoters. Additionally, IDH-wildtype diffuse astrocytic gliomas reported as WHO grade 2 or 3 demonstrated longer OS compared to grade 4 tumors (both P < .001).

CONCLUSIONS

Our findings provide the initial national OS estimates for molecularly-defined diffuse gliomas in the United States and illustrate the importance of incorporating such data into cancer registry reporting.

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.

Bio-fabricated nanodrugs with chemo-immunotherapy to inhibit glioma proliferation and recurrence

Glioblastoma multiforme (GBM) is the most malignant brain tumor with high mortality. Knowledge of the stemness concept has developed recently, giving rising to a novel hallmark with therapeutic potential that can help in management of GBM recurrence and prognosis. However, limited blood-brain barrier (BBB) penetration, non-discriminatory distribution, and deficiency of diagnosis remain three major obstacles need to be overcome for further facilitating therapeutic effects. Herein, D4F and α-Melittin (a-Mel) are co-assembled to construct bio-fabricated nanoplatforms, which endowed with inherent BBB permeability, precise tumor accumulation, deep penetration, and immune activation. After carrying arsenic trioxide (ATO) and manganese dichloride (MnCl₂), these elaborated nanodrugs, Mel-LNPs/MnAs, gather in tumor foci by natural pathways and respond to microenvironment to synchronously release Mn²⁺ and As³⁺, achieving real-time navigating-diagnosis and tumor cell proliferation inhibition. Through down regulating CD44 and CD133 expression, the GBM stemness was suppressed to overcome its high recurrence, invasion, and chemoresistance. After being combined with temozolomide (TMZ), the survival rate of GBM-bearing mice is significantly enhanced, and the rate of recurrence is powerfully limited. Collectively, this tumor-specific actuating multi-modality nanotheranostics provide a promising candidate for clinical application with high security.

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.

Novel tumor necrosis factor-related long non-coding RNAs signature for risk stratification and prognosis in glioblastoma

Background

Tumor necrosis factor (TNF) is an inflammatory cytokine that can coordinate tissue homeostasis by co-regulating the production of cytokines, cell survival, or death. It widely expresses in various tumor tissues and correlates with the malignant clinical features of patients. As an important inflammatory factor, the role of TNFα is involved in all steps of tumorigenesis and development, including cell transformation, survival, proliferation, invasion and metastasis. Recent research has showed that long non-coding RNAs (lncRNAs), defined as RNA transcripts >200 nucleotides that do not encode a protein, influence numerous cellular processes. However, little is known about the genomic profile of TNF pathway related-lncRNAs in GBM. This study investigated the molecular mechanism of TNF related-lncRNAs and their immune characteristics in glioblastoma multiforme (GBM) patients.

Methods

To identify TNF associations in GBM patients, we performed bioinformatics analysis of public databases - The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA). The ConsensusClusterPlus, CIBERSORT, Estimate, GSVA and TIDE and first-order bias correlation and so on approaches were conducted to comprehensively characterize and compare differences among TNF-related subtypes.

Results

Based on the comprehensive analysis of TNF-related lncRNAs expression profiles, we constructed six TNF-related lncRNAs (C1RL-AS1, LINC00968, MIR155HG, CPB2-AS1, LINC00906, and WDR11-AS1) risk signature to determine the role of TNF-related lncRNAs in GBM. This signature could divide GBM patients into subtypes with distinct clinical and immune characteristics and prognoses. We identified three molecular subtypes (C1, C2, and C3), with C2 showing the best prognosis; otherwise, C3 showing the worst prognosis. Moreover, we assessed the prognostic value, immune infiltration, immune checkpoints, chemokines cytokines and enrichment analysis of this signature in GBM. The TNF-related lncRNA signature was tightly associated with the regulation of tumor immune therapy and could serve as an independent prognostic biomarker in GBM.

Conclusion

This analysis provides a comprehensive understanding of the role of TNF-related characters, which may improve the clinical outcome of GBM patients.

Conventional and emerging treatments of astrocytomas and oligodendrogliomas

PURPOSE

Astrocytomas and oligodendrogliomas are mainly diffuse primary brain tumors harboring a diagnostic and prognostically favorable isocitrate dehydrogenase mutation. They are still incurable besides growing molecular knowledge and therapy options. Circumscribed astrocytomas are also discussed here, although they represent a separate entity despite similarities in the nomenclature.

METHODS

We reviewed clinical trials, preclinical approaches as well as guideline recommendations form the major scientific Neuro-Oncology organizations for astrocytomas and oligodendrogliomas according to PRISMA guidelines.

RESULTS

After histopathological diagnosis and eventually a maximal safe resection, patients with good prognostic factors may be followed by magnetic resonance imaging (MRI). If further treatment is necessary, either after diagnosis or at progression, diffuse astrocytomas and oligodendrogliomas are mainly treated with combined radiochemotherapy or maximal safe resection followed by combined radiochemotherapy according to current guidelines based on randomized trials. Circumscribed gliomas like pilocytic astrocytomas, CNS WHO grade 1, or pleomorphic xanthoastrocytomas, CNS WHO grade 2, are often treated with surgery alone. Current approaches for therapy optimization include decision of the best chemotherapy regimen. The IDH mutation presents a rational target for small molecule inhibition and immune therapy in diffuse astrocytomas and oligodendrogliomas, while the BRAF pathway is frequently mutated and treatable in circumscribed gliomas.

CONCLUSION

Despite establishment of standard treatment approaches for gliomas that include resection, radio- and chemotherapy, there is a lack of effective treatments for progressive disease. Immune- and targeted therapies are currently investigated.

A prognostic estimation model based on mRNA-sequence data for patients with oligodendroglioma

Background

The diagnosis of oligodendroglioma based on the latest World Health Organization Classification of Tumors of the Central Nervous System (WHO CNS 5) criteria requires the codeletion of chromosome arms 1p and 19q and isocitrate dehydrogenase gene (IDH) mutation (mut). Previously identified prognostic indicators may not be completely suitable for patients with oligodendroglioma based on the new diagnostic criteria. To find potential prognostic indicators for oligodendroglioma, we analyzed the expression of mRNAs of oligodendrogliomas in Chinese Glioma Genome Atlas (CGGA).

Methods

We collected 165 CGGA oligodendroglioma mRNA-sequence datasets and divided them into two cohorts. Patients in the two cohorts were further classified into long-survival and short-survival subgroups. The most predictive mRNAs were filtered out of differentially expressed mRNAs (DE mRNAs) between long-survival and short-survival patients in the training cohort by least absolute shrinkage and selection operator (LASSO), and risk scores of patients were calculated. Univariate and multivariate analyses were performed to screen factors associated with survival and establish the prognostic model. qRT-PCR was used to validate the expression differences of mRNAs.

Results

A total of 88 DE mRNAs were identified between the long-survival and the short-survival groups in the training cohort. Seven RNAs were selected to calculate risk scores. Univariate analysis showed that risk level, age, and primary-or-recurrent status (PRS) type were statistically correlated with survival and were used as factors to establish a prognostic model for patients with oligodendroglioma. The model showed an optimal predictive accuracy with a C-index of 0.912 (95% CI, 0.679-0.981) and harbored a good agreement between the predictions and observations in both training and validation cohorts.

Conclusion

We established a prognostic model based on mRNA-sequence data for patients with oligodendroglioma. The predictive ability of this model was validated in a validation cohort, which demonstrated optimal accuracy. The 7 mRNAs included in the model would help predict the prognosis of patients and guide personalized treatment.

Treatment of Adult Gliomas: A Current Update

Gliomas are the most common type of primary brain tumor in adults. Glioma treatment requires a multidisciplinary approach involving surgery, radiotherapy, and chemotherapy. Multiple trials have been conducted to establish the appropriate choice of treatment to achieve long-term survival and better quality of life. This review provides up-to-date evidence regarding treatment strategies for gliomas.

Early Postoperative Treatment versus Initial Observation in CNS WHO Grade 2 and 3 Oligodendroglioma: Clinical Outcomes and DNA Methylation Patterns

PURPOSE

The treatment of oligodendroglioma consists of tumor resection and radiochemotherapy. The timing of radiochemotherapy remains unclear, and predictive biomarkers are limited.

EXPERIMENTAL DESIGN

Adult patients diagnosed with isocitrate dehydrogenase (IDH)-mutated, 1p/19q-codeleted CNS WHO grade 2 and 3 oligodendroglioma at the Medical University of Vienna and the Kepler University Hospital Linz (Austria) in 1992 to 2019 were included. Progression-free (PFS) and overall survival (OS) between early postoperative treatment and initial observation were compared using propensity score-weighted Cox regression models. DNA methylation analysis of tumor tissue was performed using Illumina MethylationEPIC 850k microarrays.

RESULTS

One hundred thirty-one out of 201 (65.2%) patients with CNS WHO grade 2 and 70 of 201 (34.8%) with grade 3 oligodendroglioma were identified. Eighty-three of 201 (41.3%) patients underwent early postoperative treatment, of whom 56 of 83 (67.5%) received radiochemotherapy, 15 of 84 (18.1%) radiotherapy (RT) only and 12 of 83 (14.5%) chemotherapy only. Temozolomide-based treatment was administered to 64 of 68 (94.1%) patients, whereas RT + procarbazine, lomustine (CCNU), and vincristine (PCV) were applied in 2 of 69 (3.5%) patients. Early treatment was not associated with PFS [adjusted hazard ratio (HR) 0.74; 95% CI, 0.33-1.65, P = 0.459] or OS (adjusted HR: 2.07; 95% CI, 0.52-8.21, P = 0.302) improvement. Unsupervised clustering analysis of DNA methylation profiles from patients receiving early treatment revealed two methylation clusters correlating with PFS, whereas no association of clustering with O6-methylguanine methyltransferase (MGMT) promoter methylation, CNS WHO grade, extent of resection, and treating center could be observed.

CONCLUSIONS

In this retrospective study, early postoperative treatment was not associated with improved PFS/OS in oligodendroglioma. The potentially predictive value of whole-genome methylation profiling should be validated in prospective trials.

Limited efficacy of temozolomide alone for astrocytoma, IDH-mutant, CNS WHO grades 2 or 3

Purpose

The role of temozolomide chemotherapy alone in isocitrate dehydrogenase (IDH)-mutant astrocytomas has not been conclusively determined. Radiotherapy might be superior to temozolomide. Recent studies have linked temozolomide with induction of hypermutation and poor clinical course in some IDH-mutant gliomas.

Methods

In this retrospective study, 183 patients with astrocytoma, IDH-mutant, CNS WHO grade 2 or 3 and diagnosed between 2001 and 2019 were included. Patients initially monitored by wait-and-scan strategies or treated with radiotherapy or temozolomide alone were studied. Patient data were correlated with outcome. Matched pair and subgroup analyses were conducted.

Results

Radiotherapy was associated with longer progression-free survival than temozolomide (6.2 vs 3.4 years, p = 0.02) and wait-and-scan strategies (6.2 vs 4 years, p = 0.03). Patients treated with radiotherapy lived longer than patients treated with temozolomide (14.4 vs 10.7 years, p = 0.02). Survival was longer in the wait-and-scan cohort than in the temozolomide cohort (not reached vs 10.7 years, p < 0.01). Patients from the wait-and-scan cohort receiving temozolomide at first progression had significantly shorter survival times than patients treated with any other therapy at first progression (p < 0.01). Post-surgical T2 tumor volume, contrast enhancement on MRI and WHO grade were associated with overall survival in univariate analyses (p < 0.01).

Conclusion

The results suggest superiority of radiotherapy over temozolomide and wait-and-scan strategies regarding progression-free survival and superiority of radiotherapy over temozolomide regarding overall survival. Our results are consistent with the notion that early temozolomide might compromise outcome in some patients.

Radiation Therapy for IDH-Mutant Grade 2 and Grade 3 Diffuse Glioma: An ASTRO Clinical Practice Guideline

PURPOSE

This guideline provides evidence-based recommendations for adults with isocitrate dehydrogenase (IDH)-mutant grade 2 and grade 3 diffuse glioma, as classified in the 2021 World Health Organization (WHO) Classification of Tumours. It includes indications for radiation therapy (RT), advanced RT techniques, and clinical management of adverse effects.

METHODS

The American Society for Radiation Oncology convened a multidisciplinary task force to address 4 key questions focused on the RT management of patients with IDH-mutant grade 2 and grade 3 diffuse glioma. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

A strong recommendation for close surveillance alone was made for patients with oligodendroglioma, IDH-mutant, 1p/19q codeleted, WHO grade 2 after gross total resection without high-risk features. For oligodendroglioma, WHO grade 2 with any high-risk features, adjuvant RT was conditionally recommended. However, adjuvant RT was strongly recommended for oligodendroglioma, WHO grade 3. A conditional recommendation for close surveillance alone was made for astrocytoma, IDH-mutant, WHO grade 2 after gross total resection without high-risk features. Adjuvant RT was conditionally recommended for astrocytoma, WHO grade 2, with any high-risk features and strongly recommended for astrocytoma, WHO grade 3. Dose recommendations varied based on histology and grade. Given known adverse long-term effects of RT, consideration for advanced techniques such as intensity modulated radiation therapy/volumetric modulated arc therapy or proton therapy were given as strong and conditional recommendations, respectively. Finally, based on expert opinion, the guideline recommends assessment, surveillance, and management for toxicity management.

CONCLUSIONS

Based on published data, the American Society for Radiation Oncology task force has proposed recommendations to inform the management of adults with IDH-mutant grade 2 and grade 3 diffuse glioma as defined by WHO 2021 classification, based on the highest quality published data, and best translated by our task force of subject matter experts.

Joint Final Report of EORTC 26951 and RTOG 9402: Phase III Trials With Procarbazine, Lomustine, and Vincristine Chemotherapy for Anaplastic Oligodendroglial Tumors

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the basis of the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Anaplastic oligodendroglial tumors (AOTs) are chemotherapy-sensitive brain tumors. We report the final very long-term survival results from European Organization for the Research and Treatment of Cancer 26951 and Radiation Therapy Oncology Group 9402 phase III trials initiated in 1990s, which both studied radiotherapy with/without neo/adjuvant procarbazine, lomustine, and vincristine (PCV) for newly diagnosed anaplastic oligodendroglial tumors. The median follow-up duration in both was 18-19 years. For European Organization for the Research and Treatment of Cancer 26951, median, 14-year, and probable 20-year overall survival rates without versus with PCV were 2.6 years, 13.4%, and 10.1% versus 3.5 years, 25.1%, and 16.8% (N = 368 overall; hazard ratio [HR] 0.78; 95% CI, 0.63 to 0.98; P = .033), with 1p19q codeletion 9.3 years, 26.2%, and 13.6% versus 14.2 years, 51.0%, and 37.1% (n = 80; HR 0.60; 95% CI, 0.35 to 1.03; P = .063), respectively. For Radiation Therapy Oncology Group 9402, analogous results were 4.8 years, 16.5%, and 11.2% versus 4.8 years, 29.1%, and 24.6% (N = 289 overall; HR 0.79; 95% CI, 0.61 to 1.03; P = .08), with codeletion 7.3 years, 25.0%, and 14.9% versus 13.2 years, 46.1%, and 37% (n = 125; HR 0.61; 95% CI, 0.40 to 0.94; P = .02), respectively. With that, the studies show similar long-term survival even without tumor recurrence in a significant proportion of patients after first-line treatment with radiotherapy/PCV.

Influences on cognitive outcomes in adult patients with gliomas: A systematic review

People with brain tumors, including those previously treated, are commonly affected by a range of neurocognitive impairments involving executive function, memory, attention, and social/emotional functioning. Several factors are postulated to underlie this relationship, but evidence relating to many of these factors is conflicting and does not fully explain the variation in cognitive outcomes seen in the literature and in clinical practice. To address this, we performed a systematic literature review to identify and describe the range of factors that can influence cognitive outcomes in adult patients with gliomas. A literature search was performed of Ovid MEDLINE, PsychINFO, and PsycTESTS from commencement until September 2021. Of 9,998 articles identified through the search strategy, and an additional 39 articles identified through other sources, 142 were included in our review. The results confirmed that multiple factors influence cognitive outcomes in patients with gliomas. The effects of tumor characteristics (including location) and treatments administered are some of the most studied variables but the evidence for these is conflicting, which may be the result of methodological and study population differences. Tumor location and laterality overall appear to influence cognitive outcomes, and detection of such an effect is contingent upon administration of appropriate cognitive tests. Surgery appears to have an overall initial deleterious effect on cognition with a recovery in most cases over several months. A large body of evidence supports the adverse effects of radiotherapy on cognition, but the role of chemotherapy is less clear. To contrast, baseline cognitive status appears to be a consistent factor that influences cognitive outcomes, with worse baseline cognition at diagnosis/pre-treatment correlated with worse long-term outcomes. Similarly, much evidence indicates that anti-epileptic drugs have a negative effect on cognition and genetics also appear to have a role. Evidence regarding the effect of age on cognitive outcomes in glioma patients is conflicting, and there is insufficient evidence for gender and fatigue. Cognitive reserve, brain reserve, socioeconomic status, and several other variables discussed in this review, and their influence on cognition and recovery, have not been well-studied in the context of gliomas and are areas for focus in future research.

Current and Future Frontiers of Molecularly Defined Oligodendrogliomas

Oligodendrogliomas are a subtype of adult diffuse glioma characterized by their better responsiveness to systemic chemotherapy than other high-grade glial tumors. The World Health Organization (WHO) 2021 brain tumor classification highlighted defining molecular markers, including 1p19q codeletion and IDH mutations which have become key in diagnosing and treating oligodendrogliomas. The management for patients with oligodendrogliomas includes observation or surgical resection potentially followed by radiation and chemotherapy with PCV (Procarbazine, Lomustine, and Vincristine) or Temozolomide. However, most of the available research about oligodendrogliomas includes a mix of histologically and molecularly diagnosed tumors. Even data driving our current management guidelines are based on post-hoc subgroup analyses of the 1p19q codeleted population in landmark prospective trials. Therefore, the optimal treatment paradigm for molecularly defined oligodendrogliomas is incompletely understood. Many questions remain open, such as the optimal timing of radiation and chemotherapy, the response to different chemotherapeutic agents, or what genetic factors influence responsiveness to these agents. Ultimately, oligodendrogliomas are still incurable and new therapies, such as targeting IDH mutations, are necessary. In this opinion piece, we present relevant literature in the field, discuss current challenges, and propose some studies that we think are necessary to answer these critical questions.

The Network of Tumor Microtubes: An Improperly Reactivated Neural Cell Network With Stemness Feature for Resistance and Recurrence in Gliomas

Gliomas are known as an incurable brain tumor for the poor prognosis and robust recurrence. In recent years, a cellular subpopulation with tumor microtubes (TMs) was identified in brain tumors, which may provide a new angle to explain the invasion, resistance, recurrence, and heterogeneity of gliomas. Recently, it was demonstrated that the cell subpopulation also expresses neural stem cell markers and shares a lot of features with both immature neurons and cancer stem cells and may be seen as an improperly reactivated neural cell network with a stemness feature at later time points of life. TMs may also provide a new angle to understand the resistance and recurrence mechanisms of glioma stem cells. In this review, we innovatively focus on the common features between TMs and sprouting axons in morphology, formation, and function. Additionally, we summarized the recent progress in the resistance and recurrence mechanisms of gliomas with TMs and explained the incurability and heterogeneity in gliomas with TMs. Moreover, we discussed the recently discovered overlap between cancer stem cells and TM-positive glioma cells, which may contribute to the understanding of resistant glioma cell subpopulation and the exploration of the new potential therapeutic target for gliomas.

Molecular, Histological, and Clinical Characteristics of Oligodendrogliomas: A Multi-Institutional Retrospective Study

BACKGROUND

Reports suggest that phosphatidylinositol 3-kinase pathway alterations confer increased risk of progression and poor prognosis in oligodendroglioma, IDH-mutant, and 1p/19q-codeleted molecular oligodendrogliomas (mODG). However, factors that affect prognosis in mODG have not been thoroughly studied. In addition, the benefits of adjuvant radiation and temozolomide (TMZ) in mODGs remain to be determined.

OBJECTIVE

To evaluate the role of PIK3CA mutations in mODGs.

METHODS

One hundred seven mODGs (2008-2019) diagnosed at 2 institutions were included. A retrospective review of clinical characteristics, molecular alterations, treatments, and outcomes was performed.

RESULTS

The median age was 37 years, and 61 patients (57%) were male. There were 64 (60%) World Health Organization (WHO) grade 2 and 43 (40%) WHO grade 3 tumors. Eighty-two patients (77%) were stratified as high risk (age 40 years or older and/or subtotal resection per Radiation Treatment Oncology Group-9802). Gross-total resection was achieved in 47 patients (45%). Treatment strategies included observation (n = 15), TMZ (n = 11), radiation (n = 13), radiation/TMZ (n = 62), and others (n = 6). Our results show a benefit of TMZ vs observation in progression-free survival (PFS). No difference in PFS or overall survival (OS) was observed between radiation and radiation/TMZ. PIK3CA mutations were detected in 15 (14%) mODG, and shorter OS was observed in PIK3CA-mutant compared with PIK3CA wild-type mODGs (10.7 years vs 15.1 years, P = .009). WHO grade 3 tumors showed a shorter PFS, but no significant difference in OS was observed between WHO grades.

CONCLUSION

Our findings suggest that mODGs harboring PIK3CA mutations have worse OS. Except for an advantage in PFS with TMZ treatment, adjuvant TMZ, radiation, or a combination of the two showed no significant improvement in OS.

Short-term outcomes associated with temozolomide or PCV chemotherapy for 1p/19q-codeleted WHO grade 3 oligodendrogliomas: A national evaluation

Background

The optimal chemotherapy regimen between temozolomide and procarbazine, lomustine, and vincristine (PCV) remains uncertain for WHO grade 3 oligodendroglioma (Olig3) patients. We therefore investigated this question using national data.

Methods

Patients diagnosed with radiotherapy-treated 1p/19q-codeleted Olig3 between 2010 and 2018 were identified from the National Cancer Database. The overall survival (OS) associated with first-line single-agent temozolomide vs multi-agent PCV was estimated by Kaplan-Meier techniques and evaluated by multivariable Cox regression.

Results

One thousand five hundred ninety-six radiotherapy-treated 1p/19q-codeleted Olig3 patients were identified: 88.6% (n = 1414) treated with temozolomide and 11.4% (n = 182) with PCV (from 5.4% in 2010 to 12.0% in 2018) in the first-line setting. The median follow-up was 35.5 months (interquartile range [IQR] 20.7-60.6 months) with 63.3% of patients alive at the time of analysis. There was a significant difference in unadjusted OS between temozolomide (5-year OS 58.9%, 95%CI: 55.6-62.0) and PCV (5-year OS 65.1%, 95%CI: 54.8-73.5; P = .04). However, a significant OS difference between temozolomide and PCV was not observed in the Cox regression analysis adjusted by age and extent of resection (PCV vs temozolomide HR 0.81, 95%CI: 0.59-1.11, P = .18). PCV was more frequently used for younger Olig3s but otherwise was not associated with patient's insurance status or care setting.

Conclusions

In a national analysis of Olig3s, first-line PCV chemotherapy was associated with a slightly improved unadjusted short-term OS compared to temozolomide; but not following adjustment by patient age and extent of resection. There has been an increase in PCV utilization since 2010. These findings provide preliminary data while we await the definitive results from the CODEL trial.

Imaging diagnosis and treatment selection for brain tumors in the era of molecular therapeutics

Currently, most CNS tumors require tissue sampling to discern their molecular/genomic landscape. However, growing research has shown the powerful role imaging can play in non-invasively and accurately detecting the molecular signature of these tumors. The overarching theme of this review article is to provide neuroradiologists and neurooncologists with a framework of several important molecular markers, their associated imaging features and the accuracy of those features. A particular emphasis is placed on those tumors and mutations that have specific or promising imaging correlates as well as their respective therapeutic potentials.

Characteristics of Anaplastic Oligodendrogliomas Short-Term Survivors: A POLA Network Study

Background

Anaplastic oligodendrogliomas IDH-mutant and 1p/19q codeleted (AO) occasionally have a poor outcome. Herein we aimed at analyzing their characteristics.

Methods

We retrospectively analyzed the characteristics of 44 AO patients with a cancer-specific survival <5 years (short-term survivors, STS) and compared them with those of 146 AO patients with a survival ≥5 years (classical survivors, CS) included in the POLA network.

Results

Compared to CS, STS were older (P = .0001), less frequently presented with isolated seizures (P < .0001), more frequently presented with cognitive dysfunction (P < .0001), had larger tumors (P = .= .003), a higher proliferative index (P = .= .0003), and a higher number of chromosomal arm abnormalities (P = .= .02). Regarding treatment, STS less frequently underwent a surgical resection than CS (P = .= .0001) and were more frequently treated with chemotherapy alone (P = .= .009) or with radiotherapy plus temozolomide (P = .= .05). Characteristics independently associated with STS in multivariate analysis were cognitive dysfunction, a number of mitosis > 8, and the absence of tumor resection. Based on cognitive dysfunction, type of surgery, and number of mitosis, patients could be classified into groups of standard (18%) and high (62%) risk of <5 year survival.

Conclusion

The present study suggests that although STS poor outcome appears to largely result from a more advanced disease at diagnosis, surgical resection may be particularly important in this population.

Therapy for Diffuse Astrocytic and Oligodendroglial Tumors in Adults: ASCO-SNO Guideline

Purpose

To provide guidance to clinicians regarding therapy for diffuse astrocytic and oligodendroglial tumors in adults.

Methods

ASCO and the Society for Neuro-Oncology convened an Expert Panel and conducted a systematic review of the literature.

Results

Fifty-nine randomized trials focusing on therapeutic management were identified.

Recommendations

Adults with newly diagnosed oligodendroglioma, isocitrate dehydrogenase (IDH)–mutant, 1p19q codeleted CNS WHO grade 2 and 3 should be offered radiation therapy (RT) and procarbazine, lomustine, and vincristine (PCV). Temozolomide (TMZ) is a reasonable alternative for patients who may not tolerate PCV, but no high-level evidence supports upfront TMZ in this setting. People with newly diagnosed astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 2 should be offered RT with adjuvant chemotherapy (TMZ or PCV). People with astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 should be offered RT and adjuvant TMZ. People with astrocytoma, IDH-mutant, CNS WHO grade 4 may follow recommendations for either astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 or glioblastoma, IDH-wildtype, CNS WHO grade 4. Concurrent TMZ and RT should be offered to patients with newly diagnosed glioblastoma, IDH-wildtype, CNS WHO grade 4 followed by 6 months of adjuvant TMZ. Alternating electric field therapy, approved by the US Food and Drug Administration, should be considered for these patients. Bevacizumab is not recommended. In situations in which the benefits of 6-week RT plus TMZ may not outweigh the harms, hypofractionated RT plus TMZ is reasonable. In patients age ≥ 60 to ≥ 70 years, with poor performance status or for whom toxicity or prognosis are concerns, best supportive care alone, RT alone (for MGMTpromoter unmethylated tumors), or TMZ alone (for MGMT promoter methylated tumors) are reasonable treatment options. Additional information is available at www.asco.org/neurooncology-guidelines.

Therapy for Diffuse Astrocytic and Oligodendroglial Tumors in Adults: ASCO-SNO Guideline

PURPOSE

To provide guidance to clinicians regarding therapy for diffuse astrocytic and oligodendroglial tumors in adults.

METHODS

ASCO and the Society for Neuro-Oncology convened an Expert Panel and conducted a systematic review of the literature.

RESULTS

Fifty-nine randomized trials focusing on therapeutic management were identified.

RECOMMENDATIONS

Adults with newly diagnosed oligodendroglioma, isocitrate dehydrogenase (IDH)-mutant, 1p19q codeleted CNS WHO grade 2 and 3 should be offered radiation therapy (RT) and procarbazine, lomustine, and vincristine (PCV). Temozolomide (TMZ) is a reasonable alternative for patients who may not tolerate PCV, but no high-level evidence supports upfront TMZ in this setting. People with newly diagnosed astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 2 should be offered RT with adjuvant chemotherapy (TMZ or PCV). People with astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 should be offered RT and adjuvant TMZ. People with astrocytoma, IDH-mutant, CNS WHO grade 4 may follow recommendations for either astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 or glioblastoma, IDH-wildtype, CNS WHO grade 4. Concurrent TMZ and RT should be offered to patients with newly diagnosed glioblastoma, IDH-wildtype, CNS WHO grade 4 followed by 6 months of adjuvant TMZ. Alternating electric field therapy, approved by the US Food and Drug Administration, should be considered for these patients. Bevacizumab is not recommended. In situations in which the benefits of 6-week RT plus TMZ may not outweigh the harms, hypofractionated RT plus TMZ is reasonable. In patients age ≥ 60 to ≥ 70 years, with poor performance status or for whom toxicity or prognosis are concerns, best supportive care alone, RT alone (for MGMT promoter unmethylated tumors), or TMZ alone (for MGMT promoter methylated tumors) are reasonable treatment options. Additional information is available at www.asco.org/neurooncology-guidelines.

Molecular Biology in Treatment Decision Processes-Neuro-Oncology Edition

Computational approaches including machine learning, deep learning, and artificial intelligence are growing in importance in all medical specialties as large data repositories are increasingly being optimised. Radiation oncology as a discipline is at the forefront of large-scale data acquisition and well positioned towards both the production and analysis of large-scale oncologic data with the potential for clinically driven endpoints and advancement of patient outcomes. Neuro-oncology is comprised of malignancies that often carry poor prognosis and significant neurological sequelae. The analysis of radiation therapy mediated treatment and the potential for computationally mediated analyses may lead to more precise therapy by employing large scale data. We analysed the state of the literature pertaining to large scale data, computational analysis, and the advancement of molecular biomarkers in neuro-oncology with emphasis on radiation oncology. We aimed to connect existing and evolving approaches to realistic avenues for clinical implementation focusing on low grade gliomas (LGG), high grade gliomas (HGG), management of the elderly patient with HGG, rare central nervous system tumors, craniospinal irradiation, and re-irradiation to examine how computational analysis and molecular science may synergistically drive advances in personalised radiation therapy (RT) and optimise patient outcomes.

Disparities in Reported Testing for 1p/19q Codeletion in Oligodendroglioma and Oligoastrocytoma Patients: An Analysis of the National Cancer Database

Purpose

A chromosomal 1p/19q codeletion was included as a required diagnostic component of oligodendrogliomas in the 2016 World Health Organization (WHO) classification of central nervous system tumors. We sought to evaluate disparities in reported testing for 1p/19q codeletion among oligodendroglioma and oligoastrocytoma patients before and after the guidelines.

Methods

The National Cancer Database (NCDB) was queried for patients with histologically-confirmed WHO grade II/III oligodendroglioma or oligoastrocytoma from 2011-2017. Adjusted odds of having a reported 1p/19q codeletion test for patient- and hospital-level factors were calculated before (2011-2015) and after (2017) the guidelines. The adjusted likelihood of receiving adjuvant treatment (chemotherapy and/or radiotherapy) based on reported testing was also evaluated.

Results

Overall, 6,404 patients were identified. The reported 1p/19q codeletion testing rate increased from 45.8% in 2011 to 59.8% in 2017. From 2011-2015, lack of insurance (OR 0.77; 95% CI 0.62-0.97;p=0.025), lower zip code-level educational attainment (OR 0.62; 95% CI 0.49-0.78;p<0.001), and Northeast (OR 0.68; 95% CI 0.57-0.82;p<0.001) or Southern (OR 0.62; 95% CI 0.49-0.79;p<0.001) facility geographic region were negatively associated with reported testing. In 2017, Black race (OR 0.49; 95% CI 0.26-0.91;p=0.024) and Northeast (OR 0.50; 95% CI 0.30-0.84;p=0.009) or Southern (OR 0.42; 95% CI 0.22-0.78;p=0.007) region were negatively associated with reported testing. Patients with a reported test were more likely to receive adjuvant treatment (OR 1.73; 95% CI 1.46-2.04;p<0.001).

Conclusion

Despite the 2016 WHO guidelines, disparities in reported 1p/19q codeletion testing by geographic region persisted while new disparities in race/ethnicity were identified, which may influence oligodendroglioma and oligoastrocytoma patient management.

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.