Maintenance Therapy With Tumor-Treating Fields Plus Temozolomide vs Temozolomide Alone for Glioblastoma: A Randomized Clinical Trial

Targeting experimental orthotopic glioblastoma with chitosan-based superparamagnetic iron oxide nanoparticles (CS-DX-SPIONs)

Background

Glioblastoma is the most devastating primary brain tumor of the central nervous system in adults. Magnetic nanocarriers may help not only for a targeted delivery of chemotherapeutic agents into the tumor site but also provide contrast enhancing properties for diagnostics using magnetic resonance imaging (MRI).

Methods

Synthesized hybrid chitosan-dextran superparamagnetic nanoparticles (CS-DX-SPIONs) were characterized using transmission electron microscopy (TEM) and relaxometry studies. Nonlinear magnetic response measurements were employed for confirming the superparamagnetic state of particles. Following in vitro analysis of nanoparticles cellular uptake tumor targeting was assessed in the model of the orthotopic glioma in rodents.

Results

CS-DX-SPIONs nanoparticles showed a uniform diameter of 55 nm under TEM and superparamagentic characteristics as determined by T₁ (spin-lattice relaxation time) and T₂ (spin-spin relaxation time) proton relaxation times. Application of the chitosan increased the charge from +8.9 to +19.3 mV of the dextran-based SPIONs. The nonlinear magnetic response at second harmonic of CS-DX-SPIONs following the slow change of stationary magnetic fields with very low hysteresis evidenced superparamagnetic state of particles at ambient temperatures. Confocal microscopy and flow cytometry studies showed an enhanced internalization of the chitosan-based nanoparticles in U87, C6 glioma and HeLa cells as compared to dextran-coated particles. Cytotoxicity assay demonstrated acceptable toxicity profile of the synthesized nanoparticles up to a concentration of 10 μg/ml. Intravenously administered CS-DX-SPIONs in orthotopic C6 gliomas in rats accumulated in the tumor site as shown by high-resolution MRI (11.0 T). Retention of nanoparticles resulted in a significant contrast enhancement of the tumor image that was accompanied with a dramatic drop in T₂ values (P<0.001). Subsequent histological studies proved the accumulation of the nanoparticles inside glioblastoma cells.

Conclusion

Hybrid chitosan-dextran magnetic particles demonstrated high MR contrast enhancing properties for the delineation of the brain tumor. Due to a significant retention of the particles in the tumor an application of the CS-DX-SPIONs could not only improve the tumor imaging but also could allow a targeted delivery of chemotherapeutic agents.

Apelin, the Devil Inside Brain Tumors

Glioblastoma multiforme are mortifying brain tumors that contain a subpopulation of tumor cells with stem-like properties, termed as glioblastoma stem-like cells (GSCs). These GSCs constitute an autonomous reservoir of aberrant cells able to initiate, maintain, and repopulate the tumor mass. A new therapeutic strategy would consist of targeting the GSC population. The GSCs are situated in perivascular niches, closely associated with brain microvascular endothelial cells thereby involved in bidirectional molecular and cellular interactions. In this scenario, the endothelium not only supplies oxygen and necessary nutrients but also seeds a protective microenvironment for tumor growth. Although GSC fate, plasticity, and survival are regulated by external cues emanating from endothelial cells, the nature of such angiocrine signals remains unknown. Our laboratory conclusively demonstrated that brain endothelial cells positively control the expansion of GSCs.¹ Notably, we found that GSCs are addicted to the hormonal peptide apelin (APLN) secreted by surrounding endothelial cells, and identified the APLN/APLNR nexus as a promising druggable network in glioblastoma.

Modern reirradiation for recurrent gliomas can safely delay tumor progression

BACKGROUND

Despite advances in modern therapy, high-grade gliomas continue to portend a dismal prognosis and nearly all patients will experience relapse. Unfortunately, salvage options remain limited. In this study, we assessed outcomes for patients with recurrent gliomas treated with reirradiation.

METHODS

We retrospectively identified 48 glioma patients treated with reirradiation between 2013 and 2016. All had radiographic or pathologic evidence of recurrence. Prognostic factors were abstracted from the electronic medical record.

RESULTS

Initial surgery included biopsy in 15, subtotal resection in 21, and gross total resection in 12. Initial chemotherapy included temozolomide (TMZ) in 31, TMZ+dasatinib in 7, TMZ+vorinostat in 3, and procarbazine, lomustine, and vincristine in 2. The median dose of primary radiotherapy was 60 Gy delivered in 30 fractions. Median overall survival (OS) and progression-free survival (PFS) from initial diagnosis were 3.2 and 1.7 years, respectively. A total of 36 patients failed salvage bevacizumab before reirradiation. Salvage surgery was performed before reirradiation in 21 patients. Median time to reirradiation was 1.7 years. Median follow-up was 13.7 months from reirradiation. Concurrent systemic therapy was given in 33 patients (bevacizumab in 27, TMZ in 8, and lomustine in 2). Median PFS and OS after reirradiation were 3.2 and 6.3 months, respectively. Radionecrosis occurred in 4 patients and no radionecrosis was seen in patients receiving concurrent bevacizumab with reirradiation (0% vs 19%, P = .03).

CONCLUSIONS

Reirradiation may result in delayed tumor progression with acceptable toxicity. Prospective trials are needed to determine the impact of reirradiation on tumor progression and quality of life.

Dosimetric impact of tumor treating field (TTField) transducer arrays onto treatment plans for glioblastomas - a planning study

BACKGROUND

Tumor-Treating Fields (TTFields) are a novel treatment strategy for glioblastoma (GBM) that is approved for the use concomitantly to adjuvant chemotherapy. Preclinical data suggest a synergistic interaction of TTFields and radiotherapy (RT). However, the dosimetric uncertainties caused by the highly dense arrays have led to caution of applying the TTF setup during RT.

METHODS

In a RW3 slab phantom we compared the MV- and kV-CT based planned dose with the measured dose. VMAT-plans were optimized on MV-CTs of an Alderson head phantom without TTF arrays and then re-calculated on the same phantom equipped with TTF arrays. Dose at organs at risk (OAR) and target volumes (PTVs) were compared.

RESULTS

Measurements at a depth of 2, 3 and 4 cm of a RW 3 slab phantom show an attenuation due to TTField arrays of 3.4, 3.7 and 2.7% respectively. This was in-line with calculated attenuations based on MV-CT (1.2, 2.5 and 2.5%) but not with the attenuation expected from kV-CT based calculations (7.1, 8.2 and 8.6%). Consecutive MV-CT based VMAT planning and re-calculation reveals, that the conformity and homogeneity are not affected by the presence of TTField arrays. The dose at organs at risk (OAR) can show increases or decreases by < 0.5 Gy, which should be considered especially in cases next to the scull base.

CONCLUSION

MV-CT based dose calculation results in reliable dose distributions also in the presence of TTField arrays. There is a small but clinically not relevant interaction between the TTField arrays and VMAT dose application. Thus, daily replacement of TTField arrays is not necessary in regard to deeply located OARs. RT is feasible, when a VMAT treatment plan is optimized to an array free planning CT. As the biologic effect of a concomitant treatment especially on OARs is currently unknown, a concomitant treatment should be performed only within clinical trials.

β-escin selectively targets the glioblastoma-initiating cell population and reduces cell viability

Glioblastoma multiforme (GBM) is a highly aggressive tumour of the central nervous system and is associated with an extremely poor prognosis. Within GBM exists a subpopulation of cells, glioblastoma-initiating cells (GIC), which possess the characteristics of progenitor cells, have the ability to initiate tumour growth and resist to current treatment strategies. We aimed at identifying novel specific inhibitors of GIC expansion through use of a large-scale chemical screen of approved small molecules. Here, we report the identification of the natural compound β-escin as a selective inhibitor of GIC viability. Indeed, β-escin was significantly cytotoxic in nine patient-derived GIC, whilst exhibiting no substantial effect on the other human cancer or control cell lines tested. In addition, β-escin was more effective at reducing GIC growth than current clinically used cytotoxic agents. We further show that β-escin triggers caspase-dependent cell death combined with a loss of stemness properties. However, blocking apoptosis could not rescue the β-escin-induced reduction in sphere formation or stemness marker activity, indicating that β-escin directly modifies the stem identity of GIC, independent of the induction of cell death. Thus, this study has repositioned β-escin as a promising potential candidate to selectively target the aggressive population of initiating cells within GBM.

Whole-Brain Radiotherapy for Brain Metastases: Evolution or Revolution?

An estimated 20% of patients with cancer will develop brain metastases. Approximately 200,000 individuals in the United States alone receive whole-brain radiotherapy (WBRT) each year to treat brain metastases. Historically, the prognosis of patients with brain metastases has been poor; however, with new therapies, this is changing. Because patients are living longer following the diagnosis and treatment of brain metastases, there has been rising concern about treatment-related toxicities associated with WBRT, including neurocognitive toxicity. In addition, recent clinical trials have raised questions about the use of WBRT. To better understand this rapidly changing landscape, this review outlines the treatment roles and toxicities of WBRT and alternative therapies for the management of brain metastases.

MicroRNA-Based Drugs for Brain Tumors

MicroRNAs (miRNAs) are key regulatory elements encoded by the genome. A single miRNA can downregulate the expression of multiple genes involved in diverse functions. Because cancer is a disease with multiple gene aberrations, developing novel approaches to identify and modulate miRNA pathways may result in a breakthrough for cancer treatment. With a special focus on glioblastoma (GBM), this review provides an up-to-date summary of miRNA biogenesis, the role of miRNA in cancer resistance, and essential tools for modulating miRNA expression, as well as of clinically promising RNAi delivery systems and how they can be adapted for therapy.

Treatment of Glioblastoma

Glioblastoma is the most common and most aggressive form of primary brain tumor in adults and contributes to high social and medical burden as a result of its incurable nature and significant neurologic morbidity. Despite ongoing research, there has not been improvement in survival in glioblastoma. This review discusses recent advances in clinically significant molecular profiling, including IDH mutation status and O⁶-methylguanine-DNA methyltransferase ( MGMT) promoter methylation. We review updates in management of newly diagnosed and recurrent glioblastoma, as well as common difficulties in management, such as pseudoprogression and pseudoresponse. Ongoing translational research in targeted therapy and immunotherapy is briefly discussed.

The Evolving Role of Tumor Treating Fields in Managing Glioblastoma: Guide for Oncologists

Glioblastoma (GBM) is a devastating brain tumor with poor prognosis despite advances in surgery, radiation, and chemotherapy. Survival of patients with glioblastoma remains poor, with only 1 in 4 patients alive at 2 years, and a 5-year survival rate of about 5%. Recurrence is nearly universal and, after recurrence, prognosis is poor with very short progression-free survival and overall survival (OS). Various salvage chemotherapy strategies have been applied with limited success. Tumor Treating Fields (TTFields) are a novel treatment modality approved for treatment of either newly diagnosed or recurrent GBM. TTFields therapy involves a medical device and transducer arrays to provide targeted delivery of low intensity, intermediate frequency, alternating electric fields to produce antimitotic effects selective for rapidly dividing tumor cells with limited toxicity. In the phase 3 EF-14 trial, TTFields plus temozolomide provided significantly longer progression-free survival and OS compared with temozolomide alone in patients with newly diagnosed GBM after initial chemoradiotherapy. The addition of TTFields to standard therapy improved median OS from 15.6 to 20.5 months (P=0.04). In the phase 3 EF-11 trial, for recurrent GBM, TTFields provided comparable efficacy as investigator's choice systemic therapy, with improved patient-reported quality of life and a lower incidence of serious adverse events. Primary toxicity associated with TTFields is skin irritation generally managed with array relocation and topical treatments including antibiotics and steroids. TTFields therapy has demonstrated proven efficacy in management of GBM, including improvement in OS for patients with newly diagnosed GBM, and is under current investigation in other brain and extracranial tumors.

Effect of Radiation Treatment Volume Reduction on Lymphopenia in Patients Receiving Chemoradiotherapy for Glioblastoma

PURPOSE

To evaluate whether reduction in glioblastoma radiation treatment volume can reduce risk of acute severe lymphopenia (ASL).

METHODS AND MATERIALS

A total of 210 patients with supratentorial/nonmetastatic glioblastoma were treated with radiation therapy (RT) plus temozolomide from 2007 to 2016 and had laboratory data on total lymphocyte counts. Before 2015, 164 patients were treated with standard-field RT (SFRT), and limited-field RT (LFRT) was implemented thereafter for 46 patients to reduce treatment volume. Total lymphocyte counts were evaluated at baseline, during RT, and at approximately week 12 from initiating RT. Acute severe lymphopenia was defined as any total lymphocyte count < 500 cells/μL within 3 months (by week 12) of initiating RT. Multivariate analysis for overall survival (OS) was performed with Cox regression and with logistic regression for ASL. Propensity score matching was performed to adjust for variability between cohorts. Acute severe lymphopenia, progression-free survival (PFS), and OS were compared using the Kaplan-Meier method.

RESULTS

Limited-field RT patients had higher gross tumor volume than SFRT patients yet lower brain dose-volume parameters, including volume receiving 25 Gy (V25 Gy: 41% vs 53%, respectively, P < .01). Total lymphocyte count at week 12 was significantly higher for LFRT than for SFRT (median: 1100 cells/μL vs 900 cells/μL, respectively, P = .02). On multivariate analysis, ASL was an independent predictor of OS, and brain V25 Gy was an independent predictor of ASL. The ASL rate at 3 months was 15.5% for LFRT and 33.8% for SFRT (P = .12). In a propensity-matched comparison of 45 pairs of LFRT and SFRT patients, PFS (median: 5.9 vs 6.2 months, respectively, P = .58) and OS (median: 16.2 vs 13.9 months, respectively, P = .69) were not significantly different.

CONCLUSIONS

Limited-field RT is associated with less lymphopenia after RT plus temozolomide and does not adversely affect PFS or OS. Brain V25 Gy is confirmed as an important dosimetric predictor for ASL.

Intratumoral heterogeneity: pathways to treatment resistance and relapse in human glioblastoma

Intratumoral heterogeneity (ITH) has increasingly being described for multiple cancers as the root cause of therapy resistance. Recent studies have started to explore the scope of ITH in glioblastoma (GBM), a highly aggressive and fatal form of brain tumor, to explain its inevitable therapy resistance and disease relapse. In this review, we detail the emerging data that explores the extensive genetic, cellular and functional ITH present in GBM. We discuss current experimental models of human GBM recurrence and suggest harnessing new technologies (CRISPR-Cas9 screening, CyTOF, cellular barcoding, single cell analysis) to delineate GBM ITH and identify treatment-refractory cell populations, thus opening new therapeutic windows. We will also explore why current therapeutics have failed in clinical trials and how ITH can inform us on developing empiric therapies for the treatment of recurrent GBM.

Volumetric Modulated Arc (Radio) Therapy in Pets Treatment: The "La Cittadina Fondazione" Experience

Volumetric Modulated Arc Therapy (VMAT) is a modern technique, widely used in human radiotherapy, which allows a high dose to be delivered to tumor volumes and low doses to the surrounding organs at risk (OAR). Veterinary clinics takes advantage of this feature due to the small target volumes and distances between the target and the OAR. Sparing the OAR permits dose escalation, and hypofractionation regimens reduce the number of treatment sessions with a simpler manageability in the veterinary field. Multimodal volumes definition is mandatory for the small volumes involved and a positioning device precisely reproducible with a setup confirmation is needed before each session for avoiding missing the target. Additionally, the elaborate treatment plan must pursue hard constraints and objectives, and its feasibility must be evaluated with a per patient quality control. The aim of this work is to report results with regard to brain meningiomas and gliomas, trigeminal nerve tumors, brachial plexus tumors, adrenal tumors with vascular invasion and rabbit thymomas, in comparison with literature to determine if VMAT is a safe and viable alternative to surgery or chemotherapy alone, or as an adjuvant therapy in pets.

Glioblastoma in elderly patients: solid conclusions built on shifting sand?

Management of glioblastoma in the elderly population is challenging. In the near future, more than half of patients with this tumor will be over the age of 65. Clinicians have been historically reluctant to treat such patients with the same intensity as younger patients. Due to upper age limits or poor accrual of elderly patients in clinical trials, randomized data for this patient population have been relatively sparse until recently. In this review, we will discuss the concept of an elderly patient population, describe evidence for molecular differences in glioblastoma of elderly versus young patients, evaluate recent first-line trials studying glioblastoma in elderly patients, and discuss best therapeutic practices including the value of molecular testing.

Combination Therapy with Sulfasalazine and Valproic Acid Promotes Human Glioblastoma Cell Death Through Imbalance of the Intracellular Oxidative Response

Glioblastoma (GBM) is the most common and aggressive malignant primary brain tumor and still lacks effective therapeutic strategies. It has already been shown that old drugs like sulfasalazine (SAS) and valproic acid (VPA) present antitumoral activities in glioma cell lines. SAS has also been associated with a decrease of intracellular glutathione (GSH) levels through a potent inhibition of xc- glutamate/cystine exchanger leading to an antioxidant deprotection. In the same way, VPA was recently identified as a histone deacetylase (HDAT) inhibitor capable of activating tumor suppression genes. As both drugs are widely used in clinical practice and their profile of adverse effects is well known, the aim of our study was to investigate the effects of the combined treatment with SAS and VPA in GBM cell lines. We observed that both drugs were able to reduce cell viability in a dose-dependent manner and the combined treatment potentiated these effects. Combined treatment also increased cell death and inhibited proliferation of GBM cells, while having no effect on human and rat cultured astrocytes. Also, we observed high protein expression of the catalytic subunit of xc- in all the examined GBM cell lines, and treatment with SAS blocked its activity and decreased intracellular GSH levels. Noteworthy, SAS but not VPA was also able to reduce the [¹⁴C]-ascorbate uptake. Together, these data indicate that SAS and VPA exhibit a substantial effect on GBM cell's death related to an intracellular oxidative response imbalance, making this combination of drugs a promising therapeutic strategy.

From imaging to biology of glioblastoma: new clinical oncology perspectives to the problem of local recurrence

GBM is one of the most common and aggressive brain tumors. Surgery and adjuvant chemoradiation have succeeded in providing a survival benefit. Although most patients will eventually experience local recurrence, the means to fight recurrence are limited and prognosis remains poor. In a disease where local control remains the major challenge, few trials have addressed the efficacy of local treatments, either surgery or radiation therapy. The present article reviews recent advances in the biology, imaging and biomarker science of GBM as well as the current treatment status of GBM, providing new perspectives to the problem of local recurrence.

Prospective trial evaluating the sensitivity and specificity of 3,4-dihydroxy-6-[18F]-fluoro-L-phenylalanine (18F-DOPA) PET and MRI in patients with recurrent gliomas

Treatment-related changes can be difficult to differentiate from progressive glioma using MRI with contrast (CE). The purpose of this study is to compare the sensitivity and specificity of 18F-DOPA-PET and MRI in patients with recurrent glioma. Thirteen patients with MRI findings suspicious for recurrent glioma were prospectively enrolled and underwent 18F-DOPA-PET and MRI for neurosurgical planning. Stereotactic biopsies were obtained from regions of concordant and discordant PET and MRI CE, all within regions of T2/FLAIR signal hyperintensity. The sensitivity and specificity of 18F-DOPA-PET and CE were calculated based on histopathologic analysis. Receiver operating characteristic curve analysis revealed optimal tumor to normal (T/N) and SUVmax thresholds. In the 37 specimens obtained, 51% exhibited MRI contrast enhancement (M+) and 78% demonstrated 18F-DOPA-PET avidity (P+). Imaging characteristics included M-P- in 16%, M-P+ in 32%, M+P+ in 46% and M+P- in 5%. Histopathologic review of biopsies revealed grade II components in 16%, grade III in 43%, grade IV in 30% and no tumor in 11%. MRI CE sensitivity for recurrent tumor was 52% and specificity was 50%. PET sensitivity for tumor was 82% and specificity was 50%. A T/N threshold > 2.0 altered sensitivity to 76% and specificity to 100% and SUVmax > 1.36 improved sensitivity and specificity to 94 and 75%, respectively. 18F-DOPA-PET can provide increased sensitivity and specificity compared with MRI CE for visualizing the spatial distribution of recurrent gliomas. Future studies will incorporate 18F-DOPA-PET into re-irradiation target volume delineation for RT planning.

Phase 2 Study of Bortezomib Combined With Temozolomide and Regional Radiation Therapy for Upfront Treatment of Patients With Newly Diagnosed Glioblastoma Multiforme: Safety and Efficacy Assessment

PURPOSE

To assess the safety and efficacy of upfront treatment using bortezomib combined with standard radiation therapy (RT) and temozolomide (TMZ), followed by adjuvant bortezomib and TMZ for ≤24 cycles, in patients with newly diagnosed glioblastoma multiforme (GBM).

METHODS AND MATERIALS

Twenty-four patients with newly diagnosed GBM were enrolled. The patients received standard external beam regional RT with concurrent TMZ beginning 3 to 6 weeks after surgery, followed by adjuvant TMZ and bortezomib for ≤24 cycles or until tumor progression. During RT, bortezomib was given at 1.3 mg/m² on days 1, 4, 8, 11, 29, 32, 36, and 39. After RT, bortezomib was given at 1.3 mg/m² on days 1, 4, 8, and 11 every 4 weeks.

RESULTS

No unexpected adverse events occurred from the addition of bortezomib. The efficacy analysis showed a median progression-free survival (PFS) of 6.2 months (95% confidence interval [CI] 3.7-8.8), with promising PFS rates at ≥18 months compared with historical norms (25.0% at 18 and 24 months; 16.7% at 30 months). In terms of overall survival (OS), the median OS was 19.1 months (95% CI 6.7-31.4), with improved OS rates at ≥12 months (87.5% at 12, 50.0% at 24, 34.1% at 36-60 months) compared with the historical norms. The median PFS was 24.7 months (95% CI 8.5-41.0) in 10 MGMT methylated and 5.1 months (95% CI 3.9-6.2) in 13 unmethylated patients. The estimated median OS was 61 months (95% CI upper bound not reached) in the methylated and 16.4 months (95% CI 11.8-21.0) in the unmethylated patients.

CONCLUSIONS

The addition of bortezomib to current standard radiochemotherapy in newly diagnosed GBM patients was tolerable. The PFS and OS rates appeared promising, with more benefit to MGMT methylated patients. Further clinical investigation is warranted in a larger cohort of patients.

SCD1 Confers Temozolomide Resistance to Human Glioma Cells via the Akt/GSK3β/β-Catenin Signaling Axis

Resistance to temozolomide (TMZ), the standard chemotherapy agent for glioblastoma (GBM), poses a major clinical challenge to GBM prognosis. Understanding the mechanisms of TMZ resistance can help to identify novel drug targets and more effective therapies. Recent studies suggest that bioenergetic alterations of cancer cells play important roles in drug resistance. In our study, the altered metabolism of cancer cells was observed using a metabolic PCR array. We found that stearoyl-coenzyme A desaturase 1 (SCD1), a key rate-limiting enzyme for synthesis of monounsaturated fatty acids, was significantly upregulated in TMZ-resistant GBM cells compared to their parental counterparts. Overexpression of SCD1 promoted resistance to TMZ in parental GBM cells, whereas SCD1 downregulation by siRNA could re-sensitize TMZ-resistant cells in vitro. Combinational treatment of TMZ and an SCD1-specific inhibitor showed a combined inhibitory effect on TMZ-resistant glioma cells. We also observed that overexpression of SCD1 promoted Akt/GSK3β/β-catenin signaling, while silencing of SCD1 inhibited the signaling. The combination of an Akt activator with exogenous SCD1 or the combined inhibition of Akt and enforced expression of SCD1 resulted in the most significant changes of Akt signaling. Functionally, significantly lower viability and mobility rates were observed in TMZ-resistant cells when treated with Akt inhibitors and an SCD1 inhibitor simultaneously compared to when treated individually. In conclusion, our study identified SCD1 along with its functional pathway as a novel target in the development of TMZ resistance. SCD1 inhibition used alone or in combination with Akt inhibition could effectively overcome TMZ resistance in gliomas.

A Survey of the Neuro-Oncology Landscape

The field of neuro-oncology is evolving rapidly. Many important advances have recently been reported, and other promising investigations have the potential to soon make substantial impacts in the field, especially in the areas of high-grade gliomas and brain metastases. We present an overview of the current status of this field, highlighting the key recent advances as well as representative work of key clinical investigations, since these concepts have the potential to influence clinical management if they are demonstrated to be safe and efficacious. This overview includes some work that has only appeared in abstract form in order to provide a timely understanding of how the field is actively changing and what may lie on the horizon. We focus on both medical and surgical neuro-oncology advances in this highly multidisciplinary subspecialty.

Contemporary management of high-grade gliomas

High-grade gliomas, including glioblastoma, are the most common malignant brain tumors in adults. Despite intensive efforts to develop new therapies for these diseases, treatment options remain limited and prognosis is poor. Recently, there have been important advances in our understanding of the molecular basis of glioma, leading to refinements in our diagnostic and management approach. There is new evidence to guide the treatment of elderly patients. A multitude of new agents have been investigated, including targeted therapies, immunotherapeutics and tumor-treating fields. This review summarizes the key findings from this research, and presents a perspective on future opportunities to advance the field.

SEOM clinical guidelines for diagnosis and treatment of glioblastoma (2017)

Glioblastoma (GB) is the most common brain malignancy and accounts for over 50% of all high-grade gliomas. Radiotherapy (RT) with concomitant and adjuvant temozolomide (TMZ) chemotherapy is the current standard of care for patients with newly diagnosed GB up to age 70. Recently, a new standard of care has been adopted for elderly patients (≥ 65 years) based on short course of RT and TMZ. Several clinically relevant molecular markers that assist in diagnosis and prognosis have recently been identified. The treatment for recurrent GB is not well defined, and decision-making is usually based on prior strategies as well as several clinical and radiological factors. The presence of neurologic deficits and seizures can significantly impact quality of life.

Tumor treating fields (TTFields) delay DNA damage repair following radiation treatment of glioma cells

Background

Tumor Treating Fields (TTFields) are an anti-neoplastic treatment modality delivered via application of alternating electric fields using insulated transducer arrays placed directly on the skin in the region surrounding the tumor. A Phase 3 clinical trial has demonstrated the effectiveness of continuous TTFields application in patients with glioblastoma during maintenance treatment with Temozolomide. The goal of this study was to evaluate the efficacy of combining TTFields with radiation treatment (RT) in glioma cells. We also examined the effect of TTFields transducer arrays on RT distribution in a phantom model and the impact on rat skin toxicity.

Methods

The efficacy of TTFields application after induction of DNA damage by RT or bleomycin was tested in U-118 MG and LN-18 glioma cells. The alkaline comet assay was used to measure repair of DNA lesions. Repair of DNA double strand breaks (DSBs) were assessed by analyzing γH2AX or Rad51 foci. DNA damage and repair signaled by the activation pattern of phospho-ATM (pS1981) and phospho-DNA-PKcs (pS2056) was evaluated by immunoblotting. The absorption of the RT energy by transducer arrays was measured by applying RT through arrays placed on a solid-state phantom. Skin toxicities were tested in rats irradiated daily through the arrays with 2Gy (total dose of 20Gy).

Results

TTFields synergistically enhanced the efficacy of RT in glioma cells. Application of TTFields to irradiated cells impaired repair of irradiation- or chemically-induced DNA damage, possibly by blocking homologous recombination repair. Transducer arrays presence caused a minor reduction in RT intensity at 20 mm and 60 mm below the arrays, but led to a significant increase in RT dosage at the phantom surface jeopardizing the “skin sparing effect”. Nevertheless, transducer arrays placed on the rat skin during RT did not lead to additional skin reactions.

Conclusions

Administration of TTFields after RT increases glioma cells treatment efficacy possibly by inhibition of DNA damage repair. These preclinical results support the application of TTFields therapy immediately after RT as a viable regimen to enhance RT outcome. Phantom measurements and animal models imply that it may be possible to leave the transducer arrays in place during RT without increasing skin toxicities.

Electronic supplementary material

The online version of this article (10.1186/s13014-017-0941-6) contains supplementary material, which is available to authorized users.

Addition of carbonic anhydrase 9 inhibitor SLC-0111 to temozolomide treatment delays glioblastoma growth in vivo

Tumor microenvironments can promote stem cell maintenance, tumor growth, and therapeutic resistance, findings linked by the tumor-initiating cell hypothesis. Standard of care for glioblastoma (GBM) includes temozolomide chemotherapy, which is not curative, due, in part, to residual therapy-resistant brain tumor-initiating cells (BTICs). Temozolomide efficacy may be increased by targeting carbonic anhydrase 9 (CA9), a hypoxia-responsive gene important for maintaining the altered pH gradient of tumor cells. Using patient-derived GBM xenograft cells, we explored whether CA9 and CA12 inhibitor SLC-0111 could decrease GBM growth in combination with temozolomide or influence percentages of BTICs after chemotherapy. In multiple GBMs, SLC-0111 used concurrently with temozolomide reduced cell growth and induced cell cycle arrest via DNA damage in vitro. In addition, this treatment shifted tumor metabolism to a suppressed bioenergetic state in vivo. SLC-0111 also inhibited the enrichment of BTICs after temozolomide treatment determined via CD133 expression and neurosphere formation capacity. GBM xenografts treated with SLC-0111 in combination with temozolomide regressed significantly, and this effect was greater than that of temozolomide or SLC-0111 alone. We determined that SLC-0111 improves the efficacy of temozolomide to extend survival of GBM-bearing mice and should be explored as a treatment strategy in combination with current standard of care.

Advances in Brain Tumor Surgery for Glioblastoma in Adults

Glioblastoma (GBM) is the most common primary intracranial neoplasia, and is characterized by its extremely poor prognosis. Despite maximum surgery, chemotherapy, and radiation, the histological heterogeneity of GBM makes total eradication impossible, due to residual cancer cells invading the parenchyma, which is not otherwise seen in radiographic images. Even with gross total resection, the heterogeneity and the dormant nature of brain tumor initiating cells allow for therapeutic evasion, contributing to its recurrence and malignant progression, and severely impacting survival. Visual delimitation of the tumor’s margins with common surgical techniques is a challenge faced by many surgeons. In an attempt to achieve optimal safe resection, advances in approaches allowing intraoperative analysis of cancer and non-cancer tissue have been developed and applied in humans resulting in improved outcomes. In addition, functional paradigms based on stimulation techniques to map the brain’s electrical activity have optimized glioma resection in eloquent areas such as the Broca’s, Wernike’s and perirolandic areas. In this review, we will elaborate on the current standard therapy for newly diagnosed and recurrent glioblastoma with a focus on surgical approaches. We will describe current technologies used for glioma resection, such as awake craniotomy, fluorescence guided surgery, laser interstitial thermal therapy and intraoperative mass spectrometry. Additionally, we will describe a newly developed tool that has shown promising results in preclinical experiments for brain cancer: optical coherence tomography.

Effect of Tumor-Treating Fields Plus Maintenance Temozolomide vs Maintenance Temozolomide Alone on Survival in Patients With Glioblastoma: A Randomized Clinical Trial

IMPORTANCE

Tumor-treating fields (TTFields) is an antimitotic treatment modality that interferes with glioblastoma cell division and organelle assembly by delivering low-intensity alternating electric fields to the tumor.

OBJECTIVE

To investigate whether TTFields improves progression-free and overall survival of patients with glioblastoma, a fatal disease that commonly recurs at the initial tumor site or in the central nervous system.

DESIGN, SETTING, AND PARTICIPANTS

In this randomized, open-label trial, 695 patients with glioblastoma whose tumor was resected or biopsied and had completed concomitant radiochemotherapy (median time from diagnosis to randomization, 3.8 months) were enrolled at 83 centers (July 2009-2014) and followed up through December 2016. A preliminary report from this trial was published in 2015; this report describes the final analysis.

INTERVENTIONS

Patients were randomized 2:1 to TTFields plus maintenance temozolomide chemotherapy (n = 466) or temozolomide alone (n = 229). The TTFields, consisting of low-intensity, 200 kHz frequency, alternating electric fields, was delivered (≥ 18 hours/d) via 4 transducer arrays on the shaved scalp and connected to a portable device. Temozolomide was administered to both groups (150-200 mg/m2) for 5 days per 28-day cycle (6-12 cycles).

MAIN OUTCOMES AND MEASURES

Progression-free survival (tested at α = .046). The secondary end point was overall survival (tested hierarchically at α = .048). Analyses were performed for the intent-to-treat population. Adverse events were compared by group.

RESULTS

Of the 695 randomized patients (median age, 56 years; IQR, 48-63; 473 men [68%]), 637 (92%) completed the trial. Median progression-free survival from randomization was 6.7 months in the TTFields-temozolomide group and 4.0 months in the temozolomide-alone group (HR, 0.63; 95% CI, 0.52-0.76; P < .001). Median overall survival was 20.9 months in the TTFields-temozolomide group vs 16.0 months in the temozolomide-alone group (HR, 0.63; 95% CI, 0.53-0.76; P < .001). Systemic adverse event frequency was 48% in the TTFields-temozolomide group and 44% in the temozolomide-alone group. Mild to moderate skin toxicity underneath the transducer arrays occurred in 52% of patients who received TTFields-temozolomide vs no patients who received temozolomide alone.

CONCLUSIONS AND RELEVANCE

In the final analysis of this randomized clinical trial of patients with glioblastoma who had received standard radiochemotherapy, the addition of TTFields to maintenance temozolomide chemotherapy vs maintenance temozolomide alone, resulted in statistically significant improvement in progression-free survival and overall survival. These results are consistent with the previous interim analysis.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00916409.

Salvage fractionated stereotactic re-irradiation (FSRT) for patients with recurrent high grade gliomas progressed after bevacizumab treatment

Bevacizumab failure is a major clinical problem in the management of high grade gliomas (HGG), with a median overall survival (OS) of < 4 months. This study evaluated the feasibility and efficacy of fractionated stereotactic re-irradiation (FSRT) for patients progressed after Bevacizumab treatment. Retrospective review was conducted of 36 patients treated with FSRT after progression on bevacizumab. FSRT was most commonly delivered in 3.5 Gy fractions to a total dose of 35 Gy. Survival from initial diagnosis, as well as from recurrence and re-irradiation, were utilized as study endpoints. Univariate and multivariate analysis was performed. The median time from initial bevacizumab treatment to FSRT was 8.5 months. The median plan target volume for FSRT was 27.5 cc. The median OS from FSRT was 4.8 months. FSRT treatment was well tolerated with no grade 3 or higher toxicity. Favorable outcomes were observed in patients with recurrent HGG who received salvage FSRT after bevacizumab failure. The treatment was well tolerated. Prospective study is warranted to further evaluate the efficacy of salvage FSRT for selected patients with recurrent HGG amenable to FSRT, who had failed bevacizumab treatment.

Ubiquitin carboxyl-terminal hydrolase isozyme L5 inhibits human glioma cell migration and invasion via downregulating SNRPF

Ubiquitin C-terminal Hydrolase-L5 (UCH-L5/UCH37), a member of the deubiquitinases (DUBs), suppresses protein degeneration via removing ubiquitin from the distal subunit of the polyubiquitin chain. The activity of UCH-L5 is enhanced when UCH-L5 combines with proteasome 19S regulatory subunit by Rpn13/Admr1 receptor and inhibited when UCH-L5 interacts with NFRKB. But the role of UCH-L5 in gliomas remains unknown. In this study, analysis of 19 frozen and 51 paraffin-embedded clinic pathological cases showed that UCH-L5 expression in glioma tissues was lower than normal brain tissues. In vitro, we found that UCH-L5 could inhibit migration and invasion of U87MG and U251 cells. It has been reported that the expression of SNRPN, SNRPF, and CKLF was abnormal in gliomas or other tumors. We also found that SNRPF-siRNA, SNRPN-siRNA and CKLF-siRNA could inhibit migration and invasion of U87MG cells. And knockdown of UCH-L5 expression improved both mRNA expression and protein level of SNRPF. The relationship between UCH-L5 and SNRPF was further confirmed in 293T cells. Our study showed that UCH-L5 could inhibit migration and invasion of glioma cells via down regulating expression of SNRPF. And the above findings suggest that UCH-L5 may inhibit occurrence and metastasis of gliomas.

Direct medical costs of treatment in newly-diagnosed high-grade glioma among commercially insured US patients

AIM

This analysis assessed the direct medical costs of newly-diagnosed, temozolomide (TMZ)-treated glioblastoma (GBM) from the perspective of a US commercial setting.

MATERIALS AND METHODS

The analysis included subjects identified from the IMS PharMetrics LifeLink Plus™ claims database from January 1, 2008 to August 31, 2014 who were ≥18 years of age, had ≥1 malignant brain cancer diagnosis, had brain surgery ≤90 days prior to TMZ initiation, had TMZ treatment, and were continuously enrolled for ≥12 months pre-diagnosis and ≥1 month post-diagnosis. Per-patient per-month (PPPM) and cumulative costs from 3 months pre-diagnosis to various post-diagnosis follow-up time points were calculated. Multivariable analyses were used to estimate adjusted mean cost and identify contributors of cost.

RESULTS

The study included 2,921 subjects (median age = 56 years; 60% male). After diagnosis, the median (interquartile range, IQR) number of inpatient, emergency department, and outpatient visits were 2 (1-4), 1 (1-3), and 19 (13-27); median (IQR) length of stay per hospitalization was 5 (3-9) days. Mean total cumulative costs per patient from 3 months pre-diagnosis to 12 months and to 5 years post-diagnosis were $201,749 (197,490-206,024) and $268,031 (262,877-274,416). Mean (SD) PPPM costs were $818 (1,128) and $7,394 (8,676) pre- and post-GBM diagnosis, respectively. The variables most predictive of cumulative costs included radiation therapy (+$81,732), ≥2 weeks of hospitalization (+$49,629), and ≥7 MRI scans (+$40,105).

CONCLUSIONS

The direct medical costs of newly-diagnosed, TMZ-treated GBM in commercially insured patients are substantial, with estimated total cumulative costs of $268,031.

Pivotal therapeutic trials for infiltrating gliomas and how they affect clinical practice

The therapeutic landscape of the management of low- and high-grade infiltrating gliomas continues to evolve. Daily clinical decision making in neuro-oncology clinics across the US is frequently challenging, especially for anaplastic and low grade primary brain tumors. The focus of this review is centered on treatments which are approved by the FDA and/or featured in the NCCN Guidelines. Systemic therapy trials using a variety of agents such as temozolomide, bevacizumab, and procarbazine, lomustine, vincristine (PCV), and lastly trials of local therapies including surgical trials using carmustine impregnated wafers as well as trials investigating the administration of tumor treating fields are evaluated. Pivotal trials on the treatment of the primary brain tumors are discussed in detail along with associated correlative studies.

Treatment of meningioma and glioma with protons and carbon ions

The rapid rise of particle therapy across the world necessitates evidence to justify its ever-increasing utilization. This narrative review summarizes the current status of these technologies on treatment of both meningiomas and gliomas, the most common benign and malignant primary brain tumors, respectively. Proton beam therapy (PBT) for meningiomas displays high rates of long-term local control, low rates of symptomatic deterioration, along with the potential for safe dose-escalation in select (but not necessarily routine) cases. PBT is also associated with low adverse events and maintenance of functional outcomes, which have implications for quality of life and cost-effectiveness measures going forward. Data on carbon ion radiation therapy (CIRT) are limited; existing series describe virtually no high-grade toxicities and high local control. Regarding the few available data on low-grade gliomas, PBT provides opportunities to dose-escalate while affording no increase of severe toxicities, along with maintaining appropriate quality of life. Although dose-escalation for low-grade disease has been less frequently performed than for glioblastoma, PBT and CIRT continue to be utilized for the latter, and also have potential for safer re-irradiation of high-grade gliomas. For both neoplasms, the impact of superior dosimetric profiles with endpoints such as neurocognitive decline and neurologic funcionality, are also discussed to the extent of requiring more data to support the utility of particle therapy. Caveats to these data are also described, such as the largely retrospective nature of the available studies, patient selection, and heterogeneity in patient population as well as treatment (including mixed photon/particle treatment). Nevertheless, multiple prospective trials (which may partially attenuate those concerns) are also discussed. In light of the low quantity and quality of available data, major questions remain regarding economic concerns as well.

Glioma epigenetics: From subclassification to novel treatment options

Gliomas are the most common malignant primary brain tumors, of which glioblastoma is the most malignant form (WHO grade IV), and notorious for treatment resistance. Over the last decade mutations in epigenetic regulator genes have been identified as key drivers of subtypes of gliomas with distinct clinical features. Most characteristic are mutations in IDH1 or IDH2 in lower grade gliomas, and histone 3 mutations in pediatric high grade gliomas that are also associated with characteristic DNA methylation patterns. Furthermore, in adult glioblastoma patients epigenetic silencing of the DNA repair gene MGMT by promoter methylation is predictive for benefit from alkylating agent therapy. These epigenetic alterations are used as biomarkers and play a central role for classification of gliomas (WHO 2016) and treatment decisions. Here we review the pivotal role of epigenetic alterations in the etiology and biology of gliomas. We summarize the complex interactions between "driver" mutations, DNA methylation, histone post-translational modifications, and overall chromatin organization, and how they inform current efforts of testing epigenetic compounds and combinations in preclinical and clinical studies.

Yeast display biopanning identifies human antibodies targeting glioblastoma stem-like cells

Glioblastoma stem-like cells (GSC) are hypothesized to evade current therapies and cause tumor recurrence, contributing to poor patient survival. Existing cell surface markers for GSC are developed from embryonic or neural stem cell systems; however, currently available GSC markers are suboptimal in sensitivity and specificity. We hypothesized that the GSC cell surface proteome could be mined with a yeast display antibody library to reveal novel immunophenotypes. We isolated an extensive collection of antibodies that were differentially selective for GSC. A single domain antibody VH-9.7 showed selectivity for five distinct patient-derived GSC lines and visualized orthotopic GBM xenografts in vivo after conjugation with a near-infrared dye. These findings demonstrate a previously unexplored high-throughput strategy for GSC-selective antibody discovery, to aid in GSC isolation, diagnostic imaging, and therapeutic targeting.

CAR T-Cell Therapies in Glioblastoma: A First Look

Glioblastoma is an aggressive malignancy with a poor prognosis. The current standard of care for newly diagnosed glioblastoma patients includes surgery to the extent, temozolomide combined with radiotherapy, and alternating electric fields therapy. After recurrence, there is no standard therapy and survival is less than 9 months. Recurrent glioblastoma offers a unique opportunity to investigate new treatment approaches in a malignancy known for remarkable genetic heterogeneity, an immunosuppressive microenvironment, and a partially permissive anatomic blood-brain barrier. Results from three first-in-man chimeric antigen receptor (CAR) T-cell trials targeting IL13Rα2, Her2/CMV, and EGFRvIII have recently been reported. Each one of these trials addresses important questions, such as T-cell trafficking to CNS, engraftment and persistence, tumor microenvironment remodeling, and monitoring of glioma response to CAR T cells. Objective radiologic responses have been reported. Here, we discuss and summarize the results of these trials and suggest opportunities for the field. Clin Cancer Res; 24(3); 535-40. ©2017 AACR.

Initial psycho-oncological counselling in neuro-oncology: analysis of topics and needs of brain tumour patients

Diagnosis of a brain tumour is associated with a tremendous disruption of emotional, physical and social well-being. Due to the complexity of the disease and the affection of the central organ, the brain, brain tumour patients differ from other cancer patients. The purpose of this study was to evaluate the concerns and burdens presented by brain tumour patients during their initial psycho-oncological consultation. We performed a retrospective analysis of 53 patients with the diagnosis of either benign or malignant brain tumour, seeking counsel by a neurosurgeon specialised in psycho-oncology. We performed a thematic analysis of the interviews at first consultation identifying themes and patterns and created thematic categories. The main concerns of the patients presented during the first consultations were psychological problems, reported by 40 patients (75.5%). Death and dying was mentioned by more than half of the patients (n = 30, 56.6%). In addition, 62.3% of the patients (n = 33) asked for information regarding the medical treatment and diagnosis. With our study, we created greater awareness of the psychological needs of brain tumour patients in order to define treatment strategies for this important aspect of disease. We showed that there is a need for patients to talk about death even during the initial consultation. Psycho-oncologist in a neuro-oncological setting should be prepared for topics like that and should have a neurosurgical background or collaborate with members of the surgical team in order to provide the patients with medical details and to better understand the impact of the disease.

Drug Repositioning Meets Precision in Glioblastoma

Glioblastoma has a gigantic unmet medical need. Molecular knowledge has evolved substantially, including data on clonal selection with progression. Past trials for all-comers may have produced false negative results. Molecular precision at progression needs workup of new tissue, and revisiting drugs with a focus on brain tumor penetration may yield surprises. Clin Cancer Res; 24(2); 256-8. ©2017 AACRSee related article by Byron et al., p. 295.

Efficacy of a ketogenic diet with concomitant intranasal perillyl alcohol as a novel strategy for the therapy of recurrent glioblastoma

It has been hypothesized that persistent ketotic hypoglycemia represents a potential therapeutic strategy against high-grade gliomas. Perillyl alcohol (POH) is a non-toxic, naturally-occurring, hydroxylated monoterpene that exhibits cytotoxicity against temozolomide-resistant glioma cells, regardless of O6-methylguanine-methyltransferase promoter methylation status. The present study aimed to evaluate the toxicity and therapeutic efficacy of intranasal POH when administered in combination with a ketogenic diet (KD) program for the treatment of patients with recurrent glioblastoma. The 32 enrolled patients were divided into two groups, KD or standard diet, with intranasal POH treatment (n=17 and n=15, respectively). The nutritional status and anthropometric parameters of the patients were measured. Patients that adhered to the KD maintained a strict dietary regimen, in addition to receiving 55 mg POH four times daily, in an uninterrupted administration schedule for three months. Neurological examination and magnetic resonance imaging analysis were used to monitor disease progression. A total of 9/17 patients in the KD group survived and maintained compliance with the KD. After three months of well-tolerated treatment, a partial response (PR) was observed for 77.8% (7/9) of the patients, stable disease (SD) in 11.1% (1/9) and 11.1% (1/9) presented with progressive disease (PD). Among the patients assigned to the standard diet group, the PR rate was 25% (2/8 patients), SD 25% (2/8) and PD 50% (4/8 patients). The patients assigned to the KD group presented with reduced serum lipid levels and decreased low-density lipoprotein cholesterol levels. These results are encouraging and suggest that KD associated with intranasal POH may represent a viable option as an adjunct therapy for recurrent GBM.

Geographic Variations in the Incidence of Glioblastoma and Prognostic Factors Predictive of Overall Survival in US Adults from 2004-2013

Objective: The purpose of this study was to evaluate variations in the regional incidence of glioblastoma in US adults in 2004-2013. Study Design and Setting: We evaluated 24,262 patients with primary glioblastoma. Data were categorized based on geographic regions that included different SEER registry sites as follows: (1) Northeast: Connecticut, New Jersey (3,977 patients); (2) South: Kentucky, Louisiana, Metropolitan Atlanta, Rural Georgia, Greater Georgia (excluding AT and RG) (5,212 patients); (3) North Central: Metropolitan Detroit, Iowa (2,320 patients); (4) West: Hawaii, New Mexico, Seattle (Puget Sound), Utah, San Francisco-Oakland SMSA, San Jose-Monterey, Los Angeles, Greater California (excluding SF, LA, and SJ), Alaska (12,753 patients). Results: Statistically significant differences in the rates of overall patient survival (P < 0.001) and the incidence of glioblastoma (24.31, 22.6, 20.35, 15.03 per 100,000/year in the South, Northeast, West, North Central regions, respectively) were identified between geographic regions. Multivariate Cox regression analysis demonstrated that overall survival was better in patients of Asian or Pacific Islander race. In addition, age, registry site, marital status, tumor laterality, histological classification, the extent of disease, tumor size, tumor extension, and treatment methods were identified as significant prognostic factors. Conclusion: Glioblastoma incidence is geographic region and race/ethnicity-dependent.

Pharmacological targeting of apelin impairs glioblastoma growth

Glioblastoma are highly aggressive brain tumours that are associated with an extremely poor prognosis. Within these tumours exists a subpopulation of highly plastic self-renewing cancer cells that retain the ability to expand ex vivo as tumourspheres, induce tumour growth in mice, and have been implicated in radio- and chemo-resistance. Although their identity and fate are regulated by external cues emanating from endothelial cells, the nature of such signals remains unknown. Here, we used a mass spectrometry proteomic approach to characterize the factors released by brain endothelial cells. We report the identification of the vasoactive peptide apelin as a central regulator for endothelial-mediated maintenance of glioblastoma patient-derived cells with stem-like properties. Genetic and pharmacological targeting of apelin cognate receptor abrogates apelin- and endothelial-mediated expansion of glioblastoma patient-derived cells with stem-like properties in vitro and suppresses tumour growth in vivo. Functionally, selective competitive antagonists of apelin receptor were shown to be safe and effective in reducing tumour expansion and lengthening the survival of intracranially xenografted mice. Therefore, the apelin/apelin receptor signalling nexus may operate as a paracrine signal that sustains tumour cell expansion and progression, suggesting that apelin is a druggable factor in glioblastoma.

MicroRNA in Glioblastoma: An Overview

Glioblastoma is the most aggressive brain tumor and, even with the current multimodal therapy, is an invariably lethal cancer with a life expectancy that depends on the tumor subtype but, even in the most favorable cases, rarely exceeds 2 years. Epigenetic factors play an important role in gliomagenesis, are strong predictors of outcome, and are important determinants for the resistance to radio- and chemotherapy. The latest addition to the epigenetic machinery is the noncoding RNA (ncRNA), that is, RNA molecules that are not translated into a protein and that exert their function by base pairing with other nucleic acids in a reversible and nonmutational mode. MicroRNAs (miRNA) are a class of ncRNA of about 22 bp that regulate gene expression by binding to complementary sequences in the mRNA and silence its translation into proteins. MicroRNAs reversibly regulate transcription through nonmutational mechanisms; accordingly, they can be considered as epigenetic effectors. In this review, we will discuss the role of miRNA in glioma focusing on their role in drug resistance and on their potential applications in the therapy of this tumor.

Impact of academic facility type and volume on post-surgical outcomes following diagnosis of glioblastoma

OBJECTIVE

To identify if facility type and/or facility volume impact overall survival (OS) following diagnosis of glioblastoma (GBM). We also sought to compare early post-surgical outcomes based on these factors.

METHODS

The National Cancer Database was queried for patients with GBM diagnosed from 2004 to 2013 with known survival. Patients were grouped based on facility type and facility volume. Multivariable analyses were performed to investigate factors associated OS following diagnosis and Chi-square tests were used to compare early post-surgical outcomes.

RESULTS

89,839 patients met inclusion criteria. Factors associated with improved OS on multivariable analysis included younger patient age, female gender, race, lower comorbidity score, higher performance score, smaller tumor size, unifocal tumors, MGMT hypermethylation, fully resected tumors, radiotherapy, and chemotherapy (each p < .001). Also, OS was improved among patients treated at centers averaging at least 30.2 cases per year (HR 0.948, compared to <7.4 cases/year, p < .001), and patients treated at Academic/Research programs had improved survival compared to those treated at Comprehensive Community Cancer programs (HR 1.069, p < .001) and Integrated Network Cancer programs (HR 1.126, p < .001). Similarly, Academic/Research programs and high volume centers demonstrated improved 30- and 90-day morality as well as 30-day readmission rates (p < .001).

CONCLUSIONS

This study suggests that patients treated in Academic/Research programs and high patient-volume centers have increased survival and more favorable early-postsurgical outcomes. The extent to which differences in patient populations, socioeconomic factors, and/or provider expertise play into this cause will be areas of future research.

Recurrent glioma clinical trial, CheckMate-143: the game is not over yet

Glioblastoma (GBM) is the most common, and aggressive, primary brain tumor in adults. With a median patient survival of less than two years, GBM represents one of the biggest therapeutic challenges of the modern era. Even with the best available treatment, recurrence rates are nearly 100% and therapeutic options at the time of relapse are extremely limited. Nivolumab, an anti-programmed cell death-1 (PD-1) monoclonal antibody, has provided significant clinical benefits in the treatment of various advanced cancers and represented a promising therapy for primary and recurrent GBM. CheckMate 143 (NCT 02017717) was the first large randomized clinical trial of PD pathway inhibition in the setting of GBM, including a comparison of nivolumab and the anti-VEGF antibody, bevacizumab, in the treatment of recurrent disease. However, preliminary results, recently announced in a WFNOS 2017 abstract, demonstrated a failure of nivolumab to prolong overall survival of patients with recurrent GBM, and this arm of the trial was prematurely closed. In this review, we discuss the basic concepts underlying the rational to target PD pathway in GBM, address implications of using immune checkpoint inhibitors in central nervous system malignancies, provide a rationale for possible reasons contributing to the failure of nivolumab to prolong survival in patients with recurrent disease, and analyze the future role of immune checkpoint inhibitors in the treatment of GBM.