Metabolic delineation of IDH1 wild-type glioblastoma surgical anatomy: how to plan the tumor extent of resection

Engineered nanovesicles targeting SERPINE1 overcome temozolomide resistance in glioblastoma

Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with limited treatment options due to its resistance to temozolomide (TMZ). This study explores a novel therapeutic approach using engineered cell membrane nanovesicles loaded with SERPINE1 inhibitors to combat TMZ resistance. High-throughput sequencing identified pivotal genes associated with resistance, while the nanovesicles demonstrated excellent stability and the ability to cross the blood-brain barrier. Functional assays revealed significant suppression of GBM cell viability, migration, and invasion, accompanied by reduced expression of SERPINE1 and VEGF, suggesting inhibition of angiogenesis and tumor progression. These findings highlight the potential of SERPINE1-targeted nanovesicles as an innovative and effective strategy for overcoming TMZ resistance in GBM.

Quantitative evaluation of neuroradiological and morphometric alteration of inferior Fronto-Occipital Fascicle across different brain tumor histotype: an Italian multicentric study

BACKGROUND

Inferior Fronto-Occipital Fascicle (IFOF) is a multitasking connection bundle essential for communication and high level mentalization. The aim of the present study was to quantitatively assess its radiological-anatomical-morphometric modifications according to different brain tumor histotype.

METHODS

A retrospective multicentric Italian study was conducted. IFOF reconstructions were calculated for both hemispheres for each patient diagnosed with Glioblastoma (GBM), Low Grade Glioma (LGG), Brain Metastasis and Meningioma using Elements Fibertracking software (Brainlab AG). A 3D object of each fascicle was evaluated for volume, average fractional anisotropy (FA) and length. The cerebral healthy hemisphere was compared to the pathological contralateral in different tumor histotype.

RESULTS

1294 patients were evaluated. 156 met the inclusion criteria. We found a significant difference between healthy hemisphere and the contralateral for IFOF mean length and volume (p-value < 0.001). Considering GBM subgroup, Student's t-test confirmed the results. In LGG subgroup, there was significant difference between the 2 hemispheres for IFOF mean length, mean FA and volume (respectively p-value 0.011; p-value 0.021, p-value < 0.001). In patients affected by brain metastasis (18) Student's t-test showed a significant difference for FA and volume (p-value 0.003 and 0.02 respectively). No differences were found in patients affected by meningiomas.

CONCLUSIONS

The careful preoperative neuroradiological evaluation of the brain-tumor interface is indispensable to plan a tailored surgical strategy and perform a safe and effective surgical technique. It depends on the tumor histology and pattern of growth. GBM have a mixed component, with the solid enhancing nodule which accounts for IFOF displacement and the peritumoral area which accounts for an infiltrative/destructive effect on the fascicle. LGG determine a prevalent infiltrative pattern. Metastases determine an IFOF dislocation due to peritumoral oedema. Meningiomas do not impact on WM anatomy.

Standardisation of the radiological definition of supramaximal resection in glioblastoma

Glioblastoma remains the most common and lethal primary malignant brain tumour, with high rates of recurrence and progression despite gross-total resection of the contrast-enhancing region based on T1-weighted MRI. There has been growing interest in exploring "supramaximal" resections that extend beyond contrast-enhancing borders, with initial retrospective data suggesting survival benefit, but there is currently no consensus definition. In this systematic review, we explore the evolution of supramaximal resection in glioblastoma, dissect the incongruencies in the literature regarding its definition, qualitatively appraise each definition and discuss the results of various studies that have explored its impacts on patient outcomes. MEDLINE, EMBASE, SCOPUS, Cochrane Registry of Clinical Trials and Pub-MED were systematically searched for studies of glioblastoma patients who had undergone supramaximal resection. After screening and applying eligibility criteria, 25 studies were included in the final review. Definitions were grouped according to radiological modality and visualisation adjuncts and included various extents of resection of hyperintensity visualised using T2-Fluid-Attenuated Inversion Recovery, various volumetric resections of the non-contrast enhancing region, removal of methionine-uptake areas on PET, complete removal of 5-aminolevulinic acid fluorescent tissue and lobectomies. Our systematic review identified a general trend suggesting a survival benefit from supramaximal resection compared to gross-total resection but, more importantly, demonstrated the limitations of these studies due to selection bias and substantial methodological heterogeneity. Ultimately, our findings demonstrate the need for an applicable, standardised and specific definition for supramaximal resection so that prospective studies can determine prognostically significant clinical data to guide the surgical management of glioblastoma.

The State-of-the-Art PET Tracers in Glioblastoma and High-grade Gliomas and Implications for Theranostics

MR imaging is currently the main imaging modality used for the diagnosis and post therapeutic assessment of glioblastomas. Recently, several innovative PET radioactive tracers have been investigated for the evaluation of glioblastomas (GBM). These radiotracers target several biochemical and pathophysiological processes seen in tumors. These include glucose metabolism, DNA synthesis and cell proliferation, amino acid transport, cell membrane biosynthesis, specific membrane antigens such as prostatic specific membrane antigens, fibroblast activation protein inhibitor, translocator protein and hypoxia sensing agents, and antibodies targeting specific cell receptor antigen. This review aims to discuss the clinical value of these PET radiopharmaceuticals in the evaluation and treatment of GBMs.

Intraoperative Comparison Between Strain Elastography and Preoperative Magnetic Resonance Imaging Features in High-Grade Gliomas Using Fusion Imaging: A Pilot Study

OBJECTIVE

To compare the elastographic patterns of high-grade gliomas (HGGs) solid portions and those of adjacent healthy brain parenchyma, on intraoperative ultrasound, with magnetic resonance image (MRI) characteristics.

METHODS

Clinical records and images of HGGs patients, operated between June and December 2018, were retrospectively reviewed. Fusion images were used to compare preoperative gadolinium-enhanced T1-weighted MRI/fluid-attenuated inversion recovery images (Gd-T1 MRI/FLAIR) to intraoperative strain elastography (SE). FLAIR/Gd-T1 MRI images were used to define enhancement patterns (absent/whole lesion/peripheral) and lesions' characteristics (primary and secondary pattern, further subdivided in solid/necrotic/cystic/infiltrating). HGGs SE patterns were categorized as homogeneous/inhomogeneous, while lesions' primary and secondary patterns as stiff/intermediate/elastic. The SE motive of neighboring healthy brain parenchyma was defined similarly.

RESULTS

Eighteen patients (M:F, 11:7; mean age: 53 years) harboring 14 glioblastomas (77.8%) and 4 anaplastic astrocytomas (22.2%) were compared. Glioblastomas typically enhanced peripherally and had a primary necrotic pattern (78.6% and 64.3%, respectively), while anaplastic astrocytomas did not enhance and were solid (75% both) at T1-Gd MRI and FLAIR images. At SE anaplastic astrocytomas had a homogeneous stiff primary pattern, whereas the majority of glioblastomas primary patterns were heterogeneous (85.7%) and intermediate (78.6%).

CONCLUSIONS

Three major SE patterns defined HGGs and adjacent healthy brain parenchyma. SE patterns varied according to HGG histotypes and Gd-T1 MRI/FLAIR characteristics.

The Three Pillars of Glioblastoma: A Systematic Review and Novel Analysis of Multi-Omics and Clinical Data

Glioblastoma is the most fatal and common malignant brain tumor, excluding metastasis and with a median survival of approximately one year. While solid tumors benefit from newly approved drugs, immunotherapy, and prevention, none of these scenarios are opening for glioblastoma. The key to unlocking the peculiar features of glioblastoma is observing its molecular and anatomical features tightly entangled with the host's central nervous system (CNS). In June 2024, we searched the PUBMED electronic database. Data collection and analysis were conducted independently by two reviewers. Results: A total of 215 articles were identified, and 192 were excluded based on inclusion and exclusion criteria. The remaining 23 were used for collecting divergent molecular pathways and anatomical features of glioblastoma. The analysis of the selected papers revealed a multifaced tumor with extreme variability and cellular reprogramming that are observable within the same patient. All the variability of glioblastoma could be clustered into three pillars to dissect the physiology of the tumor: 1. necrotic core; 2. vascular proliferation; 3. CNS infiltration. These three pillars support glioblastoma survival, with a pivotal role of the neurovascular unit, as supported by the most recent paper published by experts in the field.

pH-Weighted amine chemical exchange saturation transfer echo planar imaging visualizes infiltrating glioblastoma cells

BACKGROUND

Given the invasive nature of glioblastoma, tumor cells exist beyond the contrast-enhancing (CE) region targeted during treatment. However, areas of non-enhancing (NE) tumors are difficult to visualize and delineate from edematous tissue. Amine chemical exchange saturation transfer echo planar imaging (CEST-EPI) is a pH-sensitive molecular magnetic resonance imaging technique that was evaluated in its ability to identify infiltrating NE tumors and prognosticate survival.

METHODS

In this prospective study, CEST-EPI was obtained in 30 patients and areas with elevated CEST contrast ("CEST+" based on the asymmetry in magnetization transfer ratio: MTRasym at 3 ppm) within NE regions were quantitated. Median MTRasym at 3 ppm and volume of CEST + NE regions were correlated with progression-free survival (PFS). In 20 samples from 14 patients, image-guided biopsies of these areas were obtained to correlate MTRasym at 3 ppm to tumor and non-tumor cell burden using immunohistochemistry.

RESULTS

In 15 newly diagnosed and 15 recurrent glioblastoma, higher median MTRasym at 3ppm within CEST + NE regions (P = .007; P = .0326) and higher volumes of CEST + NE tumor (P = .020; P < .001) were associated with decreased PFS. CE recurrence occurred in areas of preoperative CEST + NE regions in 95.4% of patients. MTRasym at 3 ppm was correlated with presence of tumor, cell density, %Ki-67 positivity, and %CD31 positivity (P = .001; P < .001; P < .001; P = .001).

CONCLUSIONS

pH-weighted amine CEST-EPI allows for visualization of NE tumor, likely through surrounding acidification of the tumor microenvironment. The magnitude and volume of CEST + NE tumor correlates with tumor cell density, degree of proliferating or "active" tumor, and PFS.

Extent of Resection and Outcomes of Patients with Primary Malignant Brain Tumors

OPINION STATEMENT

We have level II evidence that attempting a gross total resection of newly diagnosed suspected glioblastoma is preferred when a maximally safe resection can be attempted. This recommendation extends to elderly patients and those with butterfly gliomas. However, in cases where patients are poor surgical candidates, or for lesions in eloquent areas, subtotal resection or biopsy may be indicated. Recent studies have discussed "supramaximal surgery," which is defined in different ways by different teams, but there is not enough evidence, yet, to make a consistent recommendation for supramaximal resection for specific patients.

Feasibility of [18F]fluoropivalate hybrid PET/MRI for imaging lower and higher grade glioma: a prospective first-in-patient pilot study

PURPOSE

MRI and PET are used in neuro-oncology for the detection and characterisation of lesions for malignancy to target surgical biopsy and to plan surgical resections or stereotactic radiosurgery. The critical role of short-chain fatty acids (SCFAs) in brain tumour biology has come to the forefront. The non-metabolised SCFA radiotracer, [18F]fluoropivalate (FPIA), shows low background signal in most tissues except eliminating organs and has appropriate human dosimetry. Tumour uptake of the radiotracer is, however, unknown. We investigated the uptake characteristics of FPIA in this pilot PET/MRI study.

METHODS

Ten adult glioma subjects were identified based on radiological features using standard-of-care MRI prior to any surgical intervention, with subsequent histopathological confirmation of glioma subtype and grade (lower-grade - LGG - and higher-grade - HGG - patients). FPIA was injected as an intravenous bolus injection (range 342-368 MBq), and dynamic PET and MRI data were acquired simultaneously over 66 min.

RESULTS

All patients tolerated the PET/MRI protocol. Three patients were reclassified following resection and histology. Tumour maximum standardised uptake value (SUVmax,60) increased in the order LGG (WHO grade 2) < HGG (WHO grade 3) < HGG (WHO grade 4). The net irreversible solute transfer, Ki, and influx rate constant, K1, were significantly higher in HGG (p < 0.05). Of the MRI variables studied, DCE-MRI-derived extravascular-and-extracellular volume fraction (ve) was high in tumours of WHO grade 4 compared with other grades (p < 0.05). SLC25A20 protein expression was higher in HGG compared with LGG.

CONCLUSION

Tumoural FPIA PET uptake is higher in HGG compared to LGG. This study supports further investigation of FPIA PET/MRI for brain tumour imaging in a larger patient population.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov, NCT04097535.