Metabolic signatures derived from whole-brain MR-spectroscopy identify early tumor progression in high-grade gliomas using machine learning.

PURPOSE: Recurrence for high-grade gliomas is inevitable despite maximal safe resection and adjuvant chemoradiation, and current imaging techniques fall short in predicting future progression. However, we introduce a novel whole-brain magnetic resonance spectroscopy (WB-MRS) protocol that delves into the intricacies of tumor microenvironments, offering a comprehensive understanding of glioma progression to inform expectant surgical and adjuvant intervention. METHODS: We investigated five locoregional tumor metabolites in a post-treatment population and applied machine learning (ML) techniques to analyze key relationships within seven regions of interest: contralateral normal-appearing white matter (NAWM), fluid-attenuated inversion recovery (FLAIR), contrast-enhancing tumor at time of WB-MRS (Tumor), areas of future recurrence (AFR), whole-brain healthy (WBH), non-progressive FLAIR (NPF), and progressive FLAIR (PF). Five supervised ML classification models and a neural network were developed, optimized, trained, tested, and validated. Lastly, a web application was developed to host our novel calculator, the Miami Glioma Prediction Map (MGPM), for open-source interaction. RESULTS: Sixteen patients with histopathological confirmation of high-grade glioma prior to WB-MRS were included in this study, totaling 118,922 whole-brain voxels. ML models successfully differentiated normal-appearing white matter from tumor and future progression. Notably, the highest performing ML model predicted glioma progression within fluid-attenuated inversion recovery (FLAIR) signal in the post-treatment setting (mean AUC = 0.86), with Cho/Cr as the most important feature. CONCLUSIONS: This study marks a significant milestone as the first of its kind to unveil radiographic occult glioma progression in post-treatment gliomas within 8 months of discovery. These findings underscore the utility of ML-based WB-MRS growth predictions, presenting a promising avenue for the guidance of early treatment decision-making. This research represents a crucial advancement in predicting the timing and location of glioblastoma recurrence, which can inform treatment decisions to improve patient outcomes.

The Feasibility of Robot-assisted Laser Interstitial Thermal Therapy (LITT) for Brain Tumors in Octogenarians.

BACKGROUND: The use of robot-assisted laser interstitial thermal therapy (LITT) is emerging as a viable treatment option for brain tumors in patients aged 80-90 years (octogenarians). Correspondingly, the aim of this study was to describe the clinical feasibility of octogenarians undergoing LITT procedure for brain tumors at our institution. METHODS: A retrospective review was conducted of all robot-assisted LITT procedures performed at our institution between 2013 and 2023 for octogenarians. Comparison of continuous variables was by Student t tests, and Kaplan-Meier estimates were used to estimate survival outcomes. RESULTS: A total of 20 of 311 (6%) LITT patients in the search cohort were octogenarians. Mean age was 82.6 years (range, 80.1-88.0 years) with 13 (65%) female patients. Brain tumor lesions most commonly were located on the left side (65%), and, for ablation, all were single trajectories with mean number of 2.3 ablations. No operative complications were seen during hospitalization, with mean length of stay of 1.6 days and most common disposition destination being home (95%). There were no 30- or 90-day readmissions or emergency department presentations. Mean follow-up was 12.4 months without any complications in that time. The most common pathology in our cohort was glioblastoma (55%). CONCLUSIONS: Robot-assisted LITT is a safe and effective treatment option for brain tumors in octogenarians with a very low morbidity risk. Therefore, further investigation is required to understand how LITT can translate to therapeutic benefit in patients aged over 80 years old with brain tumors.

Antisense Oligonucleotides for Rapid Translation of Gene Therapy in Glioblastoma.

PURPOSE: The limited efficacy of current treatments for malignant brain tumors necessitates novel therapeutic strategies. This study aimed to assess the potential of antisense oligonucleotides (ASOs) as adjuvant therapy for high-grade gliomas, focusing on their CNS penetration and clinical translation prospects. METHODS: A comprehensive review of the existing literature was conducted to evaluate the implications of ASOs in neuro-oncology. Studies that investigated ASO therapy's efficacy, CNS penetration, and safety profile were analyzed to assess its potential as a therapeutic intervention for high-grade gliomas. RESULTS: ASOs present a promising avenue for enhancing targeted gene therapies in malignant gliomas. Their potent CNS penetration, in vivo durability, and efficient transduction offer advantages over conventional treatments. Preliminary in vivo and in vitro studies suggest ASOs as a viable adjuvant therapy for high-grade gliomas, warranting further exploration in clinical trials. CONCLUSIONS: ASOs hold significant promise as adjuvant therapy for high-grade gliomas, offering improved CNS penetration and durability compared with existing treatments. While preliminary studies are encouraging, additional research is needed to establish the safety and efficacy of ASO therapy in clinical settings. Further investigation and clinical trials are warranted to validate ASOs as a transformative approach in neuro-oncology.

Laser interstitial thermal therapy in neurosurgery: a single-surgeon experience of 313 patients.

OBJECTIVE: Real-time MRI-guided focused laser interstitial thermal therapy (LITT) is a minimally invasive surgical treatment choice for challenging intracranial lesions that are either resistant to conventional therapies or located in deep or critical areas of the brain. However, existing studies on LITT within surgical neuro-oncology are relatively small and have limited follow-up periods. The authors aimed to present a comprehensive analysis of their experiences with LITT in surgical neuro-oncology, with the intent to provide a clearer understanding of the safety and efficacy of this procedure. METHODS: This study was an exploratory cohort analysis encompassing all patients who underwent LITT for brain tumors at a single center between 2013 and 2023. The primary focus was extent of ablation (EOA), time to recurrence (TTR), and overall survival (OS). Secondary outcomes, including the rate of complications, were also evaluated. Comparative analyses were conducted based on lesion subtypes, and factors predicting outcomes were identified. RESULTS: Three hundred thirteen patients underwent LITT procedures. During a mean follow-up of 10.4 months, 66.8% of patients remained alive and 26.2% of the ablated lesions recurred. The mean age of the cohort was 60.4 ± 13.3 years (58.5% female). The lesion subtypes that were treated comprised metastases (30%), glioblastoma (GBM; 41.6%), low-grade glioma (9.1%), radiation necrosis (11.4%), and meningioma (2.2%). The permanent neurological deficit rate was 14% (n = 44), with 25 (8%) of them new-onset deficits and 19 deficits (6.1%) that were present preoperatively and did not resolve after LITT. The mean TTR and OS were 12.2 and 38.1 months, respectively. TTR and OS varied significantly by lesion subtype (p < 0.001, log-rank analysis). A high-grade lesion was identified as the single factor linked to tumor recurrence. Age, high-grade lesion, preoperative lesion volume, and readmission within 30 days were identified as factors significantly associated with OS in the multivariable Cox regression analysis. EOA > 100% predicted longer OS in metastases and GBM by log-rank analysis. CONCLUSIONS: LITT stands as a secure and feasible ablative treatment choice for intracranial lesions, potentially suitable for specific patient cases otherwise not amenable to surgical intervention. These findings further corroborate the safety of the procedure and its favorable outcomes, underscoring its potential significance in clinical practice.

Antiretroviral Drug Repositioning for Glioblastoma.

Outcomes for glioblastoma (GBM) remain poor despite standard-of-care treatments including surgical resection, radiation, and chemotherapy. Intratumoral heterogeneity contributes to treatment resistance and poor prognosis, thus demanding novel therapeutic approaches. Drug repositioning studies on antiretroviral therapy (ART) have shown promising potent antineoplastic effects in multiple cancers; however, its efficacy in GBM remains unclear. To better understand the pleiotropic anticancer effects of ART on GBM, we conducted a comprehensive drug repurposing analysis of ART in GBM to highlight its utility in translational neuro-oncology. To uncover the anticancer role of ART in GBM, we conducted a comprehensive bioinformatic and in vitro screen of antiretrovirals against glioblastoma. Using the DepMap repository and reversal of gene expression score, we conducted an unbiased screen of 16 antiretrovirals in 40 glioma cell lines to identify promising candidates for GBM drug repositioning. We utilized patient-derived neurospheres and glioma cell lines to assess neurosphere viability, proliferation, and stemness. Our in silico screen revealed that several ART drugs including reverse transcriptase inhibitors (RTIs) and protease inhibitors (PIs) demonstrated marked anti-glioma activity with the capability of reversing the GBM disease signature. RTIs effectively decreased cell viability, GBM stem cell markers, and proliferation. Our study provides mechanistic and functional insight into the utility of ART repurposing for malignant gliomas, which supports the current literature. Given their safety profile, preclinical efficacy, and neuropenetrance, ARTs may be a promising adjuvant treatment for GBM.

Minimally invasive keyhole approach for supramaximal frontal glioma resections: technical note.

OBJECTIVE: The authors aimed to review the frontal lobe's surgical anatomy, describe their keyhole frontal lobectomy technique, and analyze the surgical results. METHODS: Patients with newly diagnosed frontal gliomas treated using a keyhole approach with supramaximal resection (SMR) from 2016 to 2022 were retrospectively reviewed. Surgeries were performed on patients asleep and awake. A human donor head was dissected to demonstrate the surgical anatomy. Kaplan-Meier curves were used for survival analysis. RESULTS: Of the 790 craniotomies performed during the study period, those in 47 patients met our inclusion criteria. The minimally invasive approach involved four steps: 1) debulking the frontal pole; 2) subpial dissection identifying the sphenoid ridge, olfactory nerve, and optic nerve; 3) medial dissection to expose the falx cerebri and interhemispheric structures; and 4) posterior dissection guided by motor mapping, avoiding crossing the inferior plane defined by the corpus callosum. A fifth step could be added for nondominant lesions by resecting the inferior frontal gyrus. Perioperative complications were recorded in 5 cases (10.6%). The average hospital length of stay was 3.3 days. High-grade gliomas had a median progression-free survival of 14.8 months and overall survival of 23.9 months. CONCLUSIONS: Keyhole approaches enabled successful SMR of frontal gliomas without added risks. Robust anatomical knowledge and meticulous surgical technique are paramount for obtaining successful resections.

Bilateral Laser Interstitial Thermal Therapy for Butterfly Gliomas Compared With Needle Biopsy: A Preliminary Survival Study.

BACKGROUND AND OBJECTIVES: Bilateral/butterfly glioblastoma (bGBM) has a poor prognosis. Resection of these tumors is limited due to severe comorbidities that arise from surgical procedures. Laser interstitial thermal therapy (LITT) offers a minimally invasive cytoreductive therapy for deep-seated tumors such as bGBM. The objective of this study was to evaluate the safety of bilateral LITT in patients with bGBM. METHODS: Medical records of all consecutive patients diagnosed with bGBM by a single surgeon at a single institution from January 2014 to August 2022 were reviewed. Clinical, safety, and radiographic volumetric data were obtained. In addition, an exploratory analysis of survival was performed. RESULTS: A total of 25 patients were included; 14 underwent biopsy only, and 11 underwent biopsy + LITT (7 underwent bilateral and 4 underwent unilateral LITT). No (0%) intraoperative or postoperative complications were recorded in the treatment group. Tumor volume negatively correlated with extent of treatment (r 2 = 0.44, P = .027). The median progression-free survival was 2.8 months in the biopsy-only group and 5.5 months in the biopsy + LITT group ( P = .026). The median overall survival was 4.3 months in the biopsy-only group and 10.3 months in the biopsy + LITT group ( P = .035). CONCLUSION: Bilateral LITT for bGBM can be safely performed and shows early improvement of the progression-free survival and long-term survival outcomes of these patients.

Laser Interstitial Thermal Therapy Induces Robust Local Immune Response for Newly Diagnosed Glioblastoma With Long-term Survival and Disease Control.

Laser interstitial thermal therapy (LITT) is a minimally invasive neurosurgical technique used to ablate intra-axial brain tumors. The impact of LITT on the tumor microenvironment is scarcely reported. Nonablative LITT-induced hyperthermia (33-43˚C) increases intra-tumoral mutational burden and neoantigen production, promoting immunogenic cell death. To understand the local immune response post-LITT, we performed longitudinal molecular profiling in a newly diagnosed glioblastoma and conducted a systematic review of anti-tumoral immune responses after LITT. A 51-year-old male presented after a fall with progressive dizziness, ataxia, and worsening headaches with a small, frontal ring-enhancing lesion. After clinical and radiographic progression, the patient underwent stereotactic needle biopsy, confirming an IDH-WT World Health Organization Grade IV Glioblastoma, followed by LITT. The patient was subsequently started on adjuvant temozolomide, and 60 Gy fractionated radiotherapy to the post-LITT tumor volume. After 3 months, surgical debulking was conducted due to perilesional vasogenic edema and cognitive decline, with H&E staining demonstrating perivascular lymphocytic infiltration. Postoperative serial imaging over 3 years showed no evidence of tumor recurrence. The patient is currently alive 9 years after diagnosis. Multiplex immunofluorescence imaging of pre-LITT and post-LITT biopsies showed increased CD8 and activated macrophage infiltration and programmed death ligand 1 expression. This is the first depiction of the in-situ immune response to LITT and the first human clinical presentation of increased CD8 infiltration and programmed death ligand 1 expression in post-LITT tissue. Our findings point to LITT as a treatment approach with the potential for long-term delay of recurrence and improving response to immunotherapy.

Human endogenous retrovirus K contributes to a stem cell niche in glioblastoma.

Human endogenous retroviruses (HERVs) are ancestral viral relics that constitute nearly 8% of the human genome. Although normally silenced, the most recently integrated provirus HERV-K (HML-2) can be reactivated in certain cancers. Here, we report pathological expression of HML-2 in malignant gliomas in both cerebrospinal fluid and tumor tissue that was associated with a cancer stem cell phenotype and poor outcomes. Using single-cell RNA-Seq, we identified glioblastoma cellular populations with elevated HML-2 transcripts in neural progenitor-like cells (NPC-like) that drive cellular plasticity. Using CRISPR interference, we demonstrate that HML-2 critically maintained glioblastoma stemness and tumorigenesis in both glioblastoma neurospheres and intracranial orthotopic murine models. Additionally, we demonstrate that HML-2 critically regulated embryonic stem cell programs in NPC-derived astroglia and altered their 3D cellular morphology by activating the nuclear transcription factor OCT4, which binds to an HML-2-specific long-terminal repeat (LTR5Hs). Moreover, we discovered that some glioblastoma cells formed immature retroviral virions, and inhibiting HML-2 expression with antiretroviral drugs reduced reverse transcriptase activity in the extracellular compartment, tumor viability, and pluripotency. Our results suggest that HML-2 fundamentally contributes to the glioblastoma stem cell niche. Because persistence of glioblastoma stem cells is considered responsible for treatment resistance and recurrence, HML-2 may serve as a unique therapeutic target.

Outcomes of HSV-1 encephalitis infection in glioblastoma: An integrated systematic analysis.

INTRODUCTION: Herpes Simplex Virus-1 (HSV-1) is a neurotropic DNA virus with neural latency and stereotypic viral encephalitis. It has been reported to conceal underlying glioblastoma (GBM) due to similar radiographic imaging and clinical presentation. Limited data exist on the co-occurrence of GBM and HSV-1. To better describe the pathophysiology of HSV-1 superinfections in GBM, we performed a comprehensive review of GBM cases with superimposed HSV-1. METHODS: A comprehensive literature search of six electronic databases with apriori search criteria was performed to identify eligible cases of GBM with HSV-1. Relevant clinic-radiographic data were collected, Kaplan-Meier estimates, Fisher's exact test, and logistic regression analyses were used. RESULTS: We identified 20 cases of HSE in GBM with an overall survival (OS) of 8.0 months. The median age of presentation was 63 years (range: 24-78 years) and the median interval between GBM or HSE diagnosis was 2 months (range: 0.05-25 months). HSE diagnosis before GBM diagnosis was a predictor for improved survival (HR: 0.06; 95% CI: [0.01-0.54]; p < 0.01). There is a significant reduction in OS in patients with concomitant HSE and GBM compared to the cancer genome atlas (TCGA) cohort (median OS: 8 months vs. 14.2 months; p < 0.05). Finally, HSV does not directly infect GBM cells but indirectly activates a local immune response in the tumor microenvironment. CONCLUSIONS: Superimposed HSE in GBM may contribute to a significant reduction in OS compared to uninfected controls, potentially activating proto-oncogenes during active infection and latency. Preoperative HSE may induce an antiviral immune response, which may serve as a positive prognostic factor. Prompt antiviral treatment upon co-occurrence is necessary.

Surgical Approaches to Thalamic Gliomas: A Systematic Review.

BACKGROUND: Adult thalamic gliomas (ATGs) present a surgical challenge given their depth and proximity to eloquent brain regions. Choosing a surgical approach relies on different clinical variables such as anatomical location and size of the tumor. However, conclusive data regarding how these variables influence the balance between extent of resection and complications are lacking. We aim to systematically review the literature to describe the current surgical outcomes of ATG and to provide tools that may improve the decision-making process. METHODS: Literature regarding the surgical management of ATG patients was reviewed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Four databases were queried and a description of clinical characteristics and survival analysis were performed. An individual patient data analysis was conducted when feasible. RESULTS: A total of 462 patients were included from 13 studies. The mean age was 39.8 years with a median preoperative Karnofsky performance scale of 70. The lateral approaches were most frequently used (74.9%), followed by the interhemispheric (24.2%). Gross total and subtotal/partial resections were achieved in 81%, and 19% of all cases, respectively. New permanent neurological deficits were observed in 51/433 patients (11.8%). individual patient data was pooled from 5 studies (n = 71). In the multivariate analysis, tumors located within the posterior thalamus had worse median overall survival compared to anterior gliomas (14.5 vs. 27 months, P = 0.003). CONCLUSIONS: Surgical resection of ATGs can increase survival but at the risk of operative morbidity. Knowing which factors impact survival may allow neurosurgeons to propose a more evidence-based treatment to their patients.

Endovascular closure of a patent foramen ovale in the fat embolism syndrome: changes in the embolic patterns as detected by transcranial Doppler.

BACKGROUND: The posttraumatic fat embolism syndrome (FES) is characterized by petechiae and pulmonary and cerebral dysfunction. A patent foramen ovale (PFO) could worsen the prognosis of FES by allowing larger emboli to reach the systemic circulation. Transcranial Doppler ultrasonography can be used to diagnose and monitor cerebral microembolism in FES. OBJECTIVE: To describe a case of successful percutaneous closure of PFO in a patient with posttraumatic FES with excellent clinical outcome. PATIENT AND METHODS: A 17-year-old girl presented with a posttraumatic long-bone fracture complicated by typical severe FES. Transcranial Doppler disclosed multiple microembolic signals over both middle cerebral and basilar arteries. A large PFO was diagnosed by transesophageal echocardiogram. A brain magnetic resonance image with diffusion-weighted sequences showed multiple bilateral areas of abnormal diffusion in watershed territories. Percutaneous PFO closure with a buttoned device was successfully performed. RESULTS: Closure of PFO was associated with marked reduction in the number and intensity of microembolic signals. Subsequent surgical repair of the fracture with the patient under transcranial Doppler monitoring was uneventful. There was excellent correlation between clinical course and microembolic signal load by transcranial Doppler. CONCLUSIONS: Cerebral fat embolism after long-bone fractures can be detected in vivo and monitored over time with the use of transcranial Doppler techniques. If a PFO is present, its closure before surgical manipulation of the fracture is feasible and could have important protective effects against massive systemic embolization.