Publications by authors named "Barbara Kiesel"

61 Publications

Efficacy, Outcome, and Safety of Elderly Patients with Glioblastoma in the 5-ALA Era: Single Center Experience of More Than 10 Years.

Cancers (Basel) 2021 Dec 4;13(23). Epub 2021 Dec 4.

Department of Neurosurgery, Medical University Vienna, 1090 Vienna, Austria.

Background: In the next decades, the incidence of patients with glioblastoma (GBM) will increase due to the growth of the elderly population. Fluorescence-guided resection using 5-aminolevulinic acid (5-ALA) is widely applied to achieve maximal safe resection of GBM and is identified as a novel intraoperative marker for diagnostic tissue during biopsies. However, detailed analyses of the use of 5-ALA in resections as well as biopsies in a large elderly cohort are still missing. The aim of this study was thus to investigate the efficacy, outcome, and safety of surgically- treated GBM in the 5-ALA era in a large elderly cohort.

Methods: All GBM patients aged 65 years or older who underwent neurosurgical intervention between 2007 and 2019 were included. Data on 5-ALA application, intraoperative fluorescence status, and 5-ALA-related side effects were derived from our databank. In the case of resection, the tumor resectability and the extent of resection were determined. Potential prognostic parameters relevant for overall survival were analyzed.

Results: 272 GBM patients with a median age of 71 years were included. Intraoperative 5-ALA fluorescence was applied in most neurosurgical procedures ( = 255/272, 88%) and visible fluorescence was detected in most cases ( = 252/255, 99%). In biopsies, 5-ALA was capable of visualizing tumor tissue by visible fluorescence in all but one case ( = 91/92, 99%). 5-ALA administration did not result in any severe side effects. Regarding patient outcome, smaller preoperative tumor volume (<22.75 cm), gross total resection, single lesions, improved postoperative neurological status, and concomitant radio-chemotherapy showed a significantly longer overall survival.

Conclusions: Our data of this large elderly cohort demonstrate the clinical utility and safety of 5-ALA fluorescence in GBM for improved tumor visualization in both resections as well as biopsies. Therefore, we recommend the use of 5-ALA not only in resections, but also in open/stereotactic biopsies to optimize the neurosurgical management of elderly GBM patients.
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http://dx.doi.org/10.3390/cancers13236119DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8657316PMC
December 2021

Influence of dexamethasone on visible 5-ALA fluorescence and quantitative protoporphyrin IX accumulation measured by fluorescence lifetime imaging in glioblastomas: is pretreatment obligatory before fluorescence-guided surgery?

J Neurosurg 2021 Oct 22:1-9. Epub 2021 Oct 22.

1Department of Neurosurgery.

Objective: Fluorescence-guided surgery using 5-aminolevulinic acid (5-ALA) is nowadays widely applied for improved resection of glioblastomas (GBMs). Initially, pretreatment with dexamethasone was considered to be essential for optimal fluorescence effect. However, recent studies reported comparably high rates of visible fluorescence in GBMs despite absence of dexamethasone pretreatment. Recently, the authors proposed fluorescence lifetime imaging (FLIM) for the quantitative analysis of 5-ALA-induced protoporphyrin IX (PpIX) accumulation. The aim of this study was thus to investigate the influence of dexamethasone on visible fluorescence and quantitative PpIX accumulation.

Methods: The authors prospectively analyzed the presence of visible fluorescence during surgery in a cohort of patients with GBMs. In this study, patients received dexamethasone preoperatively only if clinically indicated. One representative tumor sample was collected from each GBM, and PpIX accumulation was analyzed ex vivo by FLIM. The visible fluorescence status and mean FLIM values were correlated with preoperative intake of dexamethasone.

Results: In total, two subgroups with (n = 27) and without (n = 20) pretreatment with dexamethasone were analyzed. All patients showed visible fluorescence independent from preoperative dexamethasone intake. Furthermore, the authors did not find a statistically significant difference in the mean FLIM values between patients with and without dexamethasone pretreatment (p = 0.097).

Conclusions: In this first study to date, the authors found no significant influence of dexamethasone pretreatment on either visible 5-ALA fluorescence during GBM surgery or PpIX accumulation based on FLIM. According to these preliminary data, the authors recommend administering dexamethasone prior to fluorescence-guided surgery of GBMs only when clinically indicated.
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http://dx.doi.org/10.3171/2021.6.JNS21940DOI Listing
October 2021

Fluorescence Lifetime Imaging and Spectroscopic Co-Validation for Protoporphyrin IX-Guided Tumor Visualization in Neurosurgery.

Front Oncol 2021 14;11:741303. Epub 2021 Sep 14.

Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.

Maximal safe resection is a key strategy for improving patient prognosis in the management of brain tumors. Intraoperative fluorescence guidance has emerged as a standard in the surgery of high-grade gliomas. The administration of 5-aminolevulinic acid prior to surgery induces tumor-specific accumulation of protoporphyrin IX, which emits red fluorescence under blue-light illumination. The technology, however, is substantially limited for low-grade gliomas and weakly tumor-infiltrated brain, where low protoporphyrin IX concentrations are outweighed by tissue autofluorescence. In this context, fluorescence lifetime imaging has shown promise to distinguish spectrally overlapping fluorophores. We integrated frequency-domain fluorescence lifetime imaging in a surgical microscope and combined it with spatially registered fluorescence spectroscopy, which can be considered a research benchmark for sensitive protoporphyrin IX detection. Fluorescence lifetime maps and spectra were acquired for a representative set of fresh brain tumor specimens (low-grade gliomas n = 15, high-grade gliomas n = 80, meningiomas n = 41, and metastases n = 35). Combining the fluorescence lifetime with fluorescence spectra unveiled how weak protoporphyrin IX accumulations increased the lifetime respective to tissue autofluorescence. Infiltration zones (4.1ns ± 1.8ns, ) and core tumor areas (4.8ns ± 1.3ns, ) of low-grade gliomas were significantly distinguishable from non-pathologic tissue (1.6ns ± 0.5ns). Similarly, fluorescence lifetimes for infiltrated and reactive tissue as well as necrotic and core tumor areas were increased for high-grade gliomas and metastasis. Meningioma tumor specimens showed strongly increased lifetimes (12.2ns ± 2.5ns, ). Our results emphasize the potential of fluorescence lifetime imaging to optimize maximal safe resection in brain tumors in future and highlight its potential toward clinical translation.
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http://dx.doi.org/10.3389/fonc.2021.741303DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8476921PMC
September 2021

Glioblastoma Surgery Imaging-Reporting and Data System: Validation and Performance of the Automated Segmentation Task.

Cancers (Basel) 2021 Sep 17;13(18). Epub 2021 Sep 17.

Department of Clinical Epidemiology and Biostatistics, Amsterdam University Medical Centers, 1105 AZ Amsterdam, The Netherlands.

For patients with presumed glioblastoma, essential tumor characteristics are determined from preoperative MR images to optimize the treatment strategy. This procedure is time-consuming and subjective, if performed by crude eyeballing or manually. The standardized GSI-RADS aims to provide neurosurgeons with automatic tumor segmentations to extract tumor features rapidly and objectively. In this study, we improved automatic tumor segmentation and compared the agreement with manual raters, describe the technical details of the different components of GSI-RADS, and determined their speed. Two recent neural network architectures were considered for the segmentation task: nnU-Net and AGU-Net. Two preprocessing schemes were introduced to investigate the tradeoff between performance and processing speed. A summarized description of the tumor feature extraction and standardized reporting process is included. The trained architectures for automatic segmentation and the code for computing the standardized report are distributed as open-source and as open-access software. Validation studies were performed on a dataset of 1594 gadolinium-enhanced T1-weighted MRI volumes from 13 hospitals and 293 T1-weighted MRI volumes from the BraTS challenge. The glioblastoma tumor core segmentation reached a Dice score slightly below 90%, a patientwise F1-score close to 99%, and a 95th percentile Hausdorff distance slightly below 4.0 mm on average with either architecture and the heavy preprocessing scheme. A patient MRI volume can be segmented in less than one minute, and a standardized report can be generated in up to five minutes. The proposed GSI-RADS software showed robust performance on a large collection of MRI volumes from various hospitals and generated results within a reasonable runtime.
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http://dx.doi.org/10.3390/cancers13184674DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8465753PMC
September 2021

5-ALA in Suspected Low-Grade Gliomas: Current Role, Limitations, and New Approaches.

Front Oncol 2021 30;11:699301. Epub 2021 Jul 30.

Department of Neurosurgery, Medical University of Vienna, Vienna, Austria.

Radiologically suspected low-grade gliomas (LGG) represent a special challenge for the neurosurgeon during surgery due to their histopathological heterogeneity and indefinite tumor margin. Therefore, new techniques are required to overcome these current surgical drawbacks. Intraoperative visualization of brain tumors with assistance of 5-aminolevulinic acid (5-ALA) induced protoporphyrin IX (PpIX) fluorescence is one of the major advancements in the neurosurgical field in the last decades. Initially, this technique was exclusively applied for fluorescence-guided surgery of high-grade glioma (HGG). In the last years, the use of 5-ALA was also extended to other indications such as radiologically suspected LGG. Here, we discuss the current role of 5-ALA for intraoperative visualization of focal malignant transformation within suspected LGG. Furthermore, we discuss the current limitations of the 5-ALA technology in pure LGG which usually cannot be visualized by visible fluorescence. Finally, we introduce new approaches based on fluorescence technology for improved detection of pure LGG tissue such as spectroscopic PpIX quantification fluorescence lifetime imaging of PpIX and confocal microscopy to optimize surgery.
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http://dx.doi.org/10.3389/fonc.2021.699301DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8362830PMC
July 2021

On the cutting edge of glioblastoma surgery: where neurosurgeons agree and disagree on surgical decisions.

J Neurosurg 2022 01 9;136(1):45-55. Epub 2021 Jul 9.

1Department of Neurosurgery, Amsterdam UMC, Vrije Universiteit, Cancer Center Amsterdam.

Objective: The aim of glioblastoma surgery is to maximize the extent of resection while preserving functional integrity. Standards are lacking for surgical decision-making, and previous studies indicate treatment variations. These shortcomings reflect the need to evaluate larger populations from different care teams. In this study, the authors used probability maps to quantify and compare surgical decision-making throughout the brain by 12 neurosurgical teams for patients with glioblastoma.

Methods: The study included all adult patients who underwent first-time glioblastoma surgery in 2012-2013 and were treated by 1 of the 12 participating neurosurgical teams. Voxel-wise probability maps of tumor location, biopsy, and resection were constructed for each team to identify and compare patient treatment variations. Brain regions with different biopsy and resection results between teams were identified and analyzed for patient functional outcome and survival.

Results: The study cohort consisted of 1087 patients, of whom 363 underwent a biopsy and 724 a resection. Biopsy and resection decisions were generally comparable between teams, providing benchmarks for probability maps of resections and biopsies for glioblastoma. Differences in biopsy rates were identified for the right superior frontal gyrus and indicated variation in biopsy decisions. Differences in resection rates were identified for the left superior parietal lobule, indicating variations in resection decisions.

Conclusions: Probability maps of glioblastoma surgery enabled capture of clinical practice decisions and indicated that teams generally agreed on which region to biopsy or to resect. However, treatment variations reflecting clinical dilemmas were observed and pinpointed by using the probability maps, which could therefore be useful for quality-of-care discussions between surgical teams for patients with glioblastoma.
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http://dx.doi.org/10.3171/2020.11.JNS202897DOI Listing
January 2022

PSMA Expression in 122 Treatment Naive Glioma Patients Related to Tumor Metabolism in C-Methionine PET and Survival.

J Pers Med 2021 Jun 30;11(7). Epub 2021 Jun 30.

Institute of Pathology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.

Apart from its expression in benign and malignant prostate tissue, prostate specific membrane antigen (PSMA) was shown to be expressed specifically in the neovasculature of solid tumors. For gliomas only little information exists. Therefore, we aimed to correlate PSMA expression in gliomas to tumor metabolism by L-[S-methyl-C]methionine (MET) PET and survival. Therefore, immunohistochemical staining (IHC) for isocitrate dehydrogenase 1-R132H (IDH1-R132H) mutation and PSMA expression was performed on the paraffin embedded tissue samples of 122 treatment-naive glioma patients. The IHC results were then related to the pre-therapeutic semiquantitative MET PET data and patients' survival. Vascular PSMA expression was observed in 26 of 122 samples and was rather specific for high-grade gliomas ([HGG] 81% of glioblastoma multiforme, 10% of WHO grade III and just 2% of grade II gliomas). Significantly higher amounts of gliomas without verifiable IDH1-R132H mutation showed vascular PSMA expression. Significantly shorter median survival times were seen for patients with vascular PSMA staining in all tumors as well as HGG only. Additionally, significantly higher numbers of PSMA staining vessels were found in tumors with high amino acid metabolic rates. Vascular PSMA expression in gliomas was seen as a high-grade specific feature associated with elevated amino acid metabolism and short survival.
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http://dx.doi.org/10.3390/jpm11070624DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8305688PMC
June 2021

Glioblastoma Surgery Imaging-Reporting and Data System: Standardized Reporting of Tumor Volume, Location, and Resectability Based on Automated Segmentations.

Cancers (Basel) 2021 Jun 8;13(12). Epub 2021 Jun 8.

Department of Neurosurgery, Amsterdam University Medical Centers, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands.

Treatment decisions for patients with presumed glioblastoma are based on tumor characteristics available from a preoperative MR scan. Tumor characteristics, including volume, location, and resectability, are often estimated or manually delineated. This process is time consuming and subjective. Hence, comparison across cohorts, trials, or registries are subject to assessment bias. In this study, we propose a standardized Glioblastoma Surgery Imaging Reporting and Data System (GSI-RADS) based on an automated method of tumor segmentation that provides standard reports on tumor features that are potentially relevant for glioblastoma surgery. As clinical validation, we determine the agreement in extracted tumor features between the automated method and the current standard of manual segmentations from routine clinical MR scans before treatment. In an observational consecutive cohort of 1596 adult patients with a first time surgery of a glioblastoma from 13 institutions, we segmented gadolinium-enhanced tumor parts both by a human rater and by an automated algorithm. Tumor features were extracted from segmentations of both methods and compared to assess differences, concordance, and equivalence. The laterality, contralateral infiltration, and the laterality indices were in excellent agreement. The native and normalized tumor volumes had excellent agreement, consistency, and equivalence. Multifocality, but not the number of foci, had good agreement and equivalence. The location profiles of cortical and subcortical structures were in excellent agreement. The expected residual tumor volumes and resectability indices had excellent agreement, consistency, and equivalence. Tumor probability maps were in good agreement. In conclusion, automated segmentations are in excellent agreement with manual segmentations and practically equivalent regarding tumor features that are potentially relevant for neurosurgical purposes. Standard GSI-RADS reports can be generated by open access software.
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http://dx.doi.org/10.3390/cancers13122854DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8229389PMC
June 2021

Influence of preoperative corticosteroid treatment on rate of diagnostic surgeries in primary central nervous system lymphoma: a multicenter retrospective study.

BMC Cancer 2021 Jun 29;21(1):754. Epub 2021 Jun 29.

Department of Neurosurgery, Medical University Vienna, Vienna, Austria.

Background: Corticosteroid therapy (CST) prior to biopsy may hinder histopathological diagnosis in primary central nervous system lymphoma (PCNSL). Therefore, preoperative CST in patients with suspected PCNSL should be avoided if clinically possible. The aim of this study was thus to analyze the difference in the rate of diagnostic surgeries in PCNSL patients with and without preoperative CST.

Methods: A multicenter retrospective study including all immunocompetent patients diagnosed with PCNSL between 1/2004 and 9/2018 at four neurosurgical centers in Austria was conducted and the results were compared to literature.

Results: A total of 143 patients were included in this study. All patients showed visible contrast enhancement on preoperative MRI. There was no statistically significant difference in the rate of diagnostic surgeries with and without preoperative CST with 97.1% (68/70) and 97.3% (71/73), respectively (p = 1.0). Tapering and pause of CST did not influence the diagnostic rate. Including our study, there are 788 PCNSL patients described in literature with an odds ratio for inconclusive surgeries after CST of 3.3 (CI 1.7-6.4).

Conclusions: Preoperative CST should be avoided as it seems to diminish the diagnostic rate of biopsy in PCNSL patients. Yet, if CST has been administered preoperatively and there is still a contrast enhancing lesion to target for biopsy, surgeons should try to keep the diagnostic delay to a minimum as the likelihood for acquiring diagnostic tissue seems sufficiently high.
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http://dx.doi.org/10.1186/s12885-021-08515-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8243818PMC
June 2021

Androgen Receptor is Expressed in Breast Cancer Brain Metastases.

Appl Immunohistochem Mol Morphol 2021 Nov-Dec 01;29(10):728-733

Department of Medicine I, Division of Oncology.

Background: Androgen receptor (AR) expression is a potential therapeutic target in breast cancer (BC) as it is frequently expressed in the luminal A and B subtypes and in approximately one third of basal-like cancers. As AR-positive BC displays a distinct biological behavior, we aimed to analyze AR expression in the particular context of BC brain metastases (BM).

Materials And Methods: Patients with newly diagnosed BC BM treated with neurosurgical resection were identified from the Vienna Brain Metastasis Registry and clinical data including patient characteristics, biological tumor subtypes and overall survival were obtained by retrospective chart review. Formalin-fixed and paraffin-embedded specimen containing BM tissue were retrieved from the Neuro-Biobank. Immunohistochemical staining of AR was performed and AR expression in the tumor-cell nucleus was evaluated.

Results: Fifty-seven BM samples from 57 individual patients with BC were available for this analysis. AR expression of ≥1% tumor cells was evident in 20/57 (35.1%) BM specimens; the median AR-expression rate was 10% (range: 1% to 60%). AR expression was observed in 11/21 (52.4%) BM of the luminal/human epidermal growth factor receptor 2 (HER2)-negative subtype, 3/13 (23.1%) of the luminal/HER2-positive subtype, 2/7 (28.6%) of the HER2-positive subtype and 4/16 (25.0%) of the triple-negative subtype (P=0.247). Median survival from diagnosis of BM was 10 months (range: 0 to 104 mo) in the entire cohort. No significant association of overall survival and AR expression ≥1% was observed (15 vs. 13 mo; P>0.05).

Conclusion: AR is expressed in more than one third of BC BM with the highest rates among the luminal/HER2-negative BC subtype and may therefore be a potential prognostic and predictive biomarker in this particular BC population.
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http://dx.doi.org/10.1097/PAI.0000000000000952DOI Listing
November 2020

5-ALA Fluorescence Is a Powerful Prognostic Marker during Surgery of Low-Grade Gliomas (WHO Grade II)-Experience at Two Specialized Centers.

Cancers (Basel) 2021 May 21;13(11). Epub 2021 May 21.

Department of Neurosurgery, Medical University of Vienna, 1090 Vienna, Austria.

The prediction of the individual prognosis of low-grade glioma (LGG) patients is limited in routine clinical practice. Nowadays, 5-aminolevulinic acid (5-ALA) fluorescence is primarily applied for improved intraoperative visualization of high-grade gliomas. However, visible fluorescence is also observed in rare cases despite LGG histopathology and might be an indicator for aggressive tumor behavior. The aim of this study was thus to investigate the value of intraoperative 5-ALA fluorescence for prognosis in LGG patients. We performed a retrospective analysis of patients with newly diagnosed histopathologically confirmed LGG and preoperative 5-ALA administration at two independent specialized centers. In this cohort, we correlated the visible intraoperative fluorescence status with progression-free survival (PFS), malignant transformation-free survival (MTFS) and overall survival (OS). Altogether, visible fluorescence was detected in 7 (12%) of 59 included patients in focal intratumoral areas. At a mean follow-up time of 5.3 ± 2.9 years, patients with fluorescing LGG had significantly shorter PFS (2.3 ± 0.7 vs. 5.0 ± 0.4 years; 0.01), MTFS (3.9 ± 0.7 vs. 8.0 ± 0.6 years; = 0.03), and OS (5.4 ± 1.0 vs. 10.3 ± 0.5 years; = 0.01) than non-fluorescing tumors. Our data indicate that visible 5-ALA fluorescence during surgery of pure LGG might be an already intraoperatively available marker of unfavorable patient outcome and thus close imaging follow-up might be considered.
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http://dx.doi.org/10.3390/cancers13112540DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8196836PMC
May 2021

Timing of glioblastoma surgery and patient outcomes: a multicenter cohort study.

Neurooncol Adv 2021 Jan-Dec;3(1):vdab053. Epub 2021 Apr 8.

Amsterdam University Medical Centers, location VU University Medical Center, Neurosurgical Center Amsterdam, Amsterdam, Netherlands.

Background: The impact of time-to-surgery on clinical outcome for patients with glioblastoma has not been determined. Any delay in treatment is perceived as detrimental, but guidelines do not specify acceptable timings. In this study, we relate the time to glioblastoma surgery with the extent of resection and residual tumor volume, performance change, and survival, and we explore the identification of patients for urgent surgery.

Methods: Adults with first-time surgery in 2012-2013 treated by 12 neuro-oncological teams were included in this study. We defined time-to-surgery as the number of days between the diagnostic MR scan and surgery. The relation between time-to-surgery and patient and tumor characteristics was explored in time-to-event analysis and proportional hazard models. Outcome according to time-to-surgery was analyzed by volumetric measurements, changes in performance status, and survival analysis with patient and tumor characteristics as modifiers.

Results: Included were 1033 patients of whom 729 had a resection and 304 a biopsy. The overall median time-to-surgery was 13 days. Surgery was within 3 days for 235 (23%) patients, and within a month for 889 (86%). The median volumetric doubling time was 22 days. Lower performance status (hazard ratio [HR] 0.942, 95% confidence interval [CI] 0.893-0.994) and larger tumor volume (HR 1.012, 95% CI 1.010-1.014) were independently associated with a shorter time-to-surgery. Extent of resection, residual tumor volume, postoperative performance change, and overall survival were not associated with time-to-surgery.

Conclusions: With current decision-making for urgent surgery in selected patients with glioblastoma and surgery typically within 1 month, we found equal extent of resection, residual tumor volume, performance status, and survival after longer times-to-surgery.
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http://dx.doi.org/10.1093/noajnl/vdab053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8156977PMC
April 2021

Favourable outcome of patients with breast cancer brain metastases treated with dual HER2 blockade of trastuzumab and pertuzumab.

Ther Adv Med Oncol 2021 22;13:17588359211009002. Epub 2021 Apr 22.

Division of Oncology, Department of Medicine 1, Medical University of Vienna, Austria.

Background: Dual human epidermal growth factor receptor 2 (HER2) blockade with trastuzumab and pertuzumab (TP) is a standard therapy of metastatic and localized HER2-positive breast cancer (BC), but its activity in breast cancer brain metastases (BCBM) is unknown.

Methods: Patients with HER2-positive BCBM were identified from the Vienna Brain Metastasis Registry and clinical data including patient characteristics, therapies and overall survival (OS) were obtained. Patients were grouped into 'TP', 'other-HER2-targeted therapy' and 'no-HER2-targeted therapy' according to received first-line systemic therapy after diagnosis of BCBM. Radiological re-assessment of intracranial lesions was performed in patients treated with TP as systemic first-line therapy according to RANO response criteria for brain metastases (BM).

Results: A total of 252 HER2-positive BC patients with BM were available for this analysis. Patients treated with TP as systemic first-line therapy after diagnosis of BM had a significantly longer OS compared with treatment with other-HER2-targeted therapy and no-HER2-targeted therapy (44 17 3 months,  < 0.001; log-rank test). Among radiologically re-assessed patients treated with TP as systemic first-line therapy after diagnosis of BM, 5/14 patients (35.7%) had complete intracranial remission (CR), 8/14 patients (57.1%) partial intracranial remission (PR), 1/14 patients (7.1%) stable intracranial disease (SD) and 0/14 patients (0.0%) progressive intracranial disease (PD) as best response resulting in an intracranial objective response rate (iORR) of 92.9% and an intracranial clinical benefit rate (iCBR) of 100.0%.

Conclusion: First-line therapy with dual HER2-inhibition of TP after BM diagnosis was associated with the longest median OS times in patients with BCBM.
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http://dx.doi.org/10.1177/17588359211009002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8072867PMC
April 2021

Circulating PD-L1 levels change during bevacizumab-based treatment in recurrent glioma.

Cancer Immunol Immunother 2021 Dec 6;70(12):3643-3650. Epub 2021 May 6.

Department of Medicine I, Division of Oncology, Medical University of Vienna, Vienna, Austria.

Purpose: In primary brain tumors, the efficacy of immune-modulating therapies is still under investigation as inflammatory responses are restricted by tight immunoregulatory mechanisms in the central nervous system. Here, we measured soluble PD-L1 (sPD-L1) in the plasma of patients with recurrent glioblastoma (GBM) and recurrent WHO grade II-III glioma treated with bevacizumab-based salvage therapy.

Methods: Thirty patients with recurrent GBM and 10 patients with recurrent WHO grade II-III glioma were treated with bevacizumab-based salvage therapy at the Medical University of Vienna. Prior to each treatment cycle, EDTA plasma was drawn and sPD-L1 was measured applying a sandwich ELISA with a lower detection limit of 0.050 ng/ml. Leukocyte counts and C-reactive protein (CRP) levels were measured according to institutional practice.

Results: Median number of sPD-L1 measurements was 6 per patient (range: 2-24). At baseline, no significant difference in sPD-L1 concentrations was observed between WHO grade II-III glioma and GBM. Intra-patient variability of sPD-L1 concentrations was significantly higher in WHO grade II-III glioma than in GBM (p = 0.014) and tendentially higher in IDH-mutant than in IDH-wildtype glioma (p = 0.149) In WHO grade II-III glioma, sPD-L1 levels were significantly lower after one administration of bevacizumab than at baseline (median: 0.039 ng/ml vs. 0.4855 ng/ml, p = 0.036). In contrast, no significant change could be observed in patients with GBM.

Conclusions: Changes in systemic inflammation markers including sPD-L1 are observable in patients with recurrent glioma under bevacizumab-based treatment and differ between WHO grade II-III glioma and GBM.
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http://dx.doi.org/10.1007/s00262-021-02951-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8571215PMC
December 2021

Robust Deep Learning-based Segmentation of Glioblastoma on Routine Clinical MRI Scans Using Sparsified Training.

Radiol Artif Intell 2020 Sep 30;2(5):e190103. Epub 2020 Sep 30.

Department of Radiation Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands (R.S.E., M.v.H., M.G.W.); Department of Radiology and Nuclear Medicine, Amsterdam UMC, Location Vrije Universiteit Amsterdam, Amsterdam, the Netherlands (M.V., F.B., H.V., J.C.d.M.); Neurosurgical Center Amsterdam, Amsterdam UMC, Location Vrije Universiteit Amsterdam, Amsterdam, the Netherlands (D.M.J.M., P.C.D.W.H.); Institutes of Neurology & Healthcare Engineering, University College London, London, England (F.B.); Faculty of Biology, Medicine & Health, Division of Cancer Sciences, University of Manchester and Christie NHS Trust, Manchester, England (M.v.H.); Neurosurgical Oncology Unit, Department of Oncology and Hemato-Oncology, Università degli Studi di Milano, Humanitas Research Hospital, IRCCS, Milan, Italy (L.B., M.C.N., M.R., T.S.); Department of Neurologic Surgery, University of California-San Francisco, San Francisco, Calif (M.S.B., S.H.J.); Department of Neurosurgery, Medical University Vienna, Vienna, Austria (B.K., G.W.); Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria (J.F.); Department of Neurology & Neurosurgery, University Medical Center Utrecht, Utrecht, the Netherlands (P.A.J.T.R.); and Department of Neurologic Surgery, Hôpital Lariboisière, Paris, France (E.M.).

Purpose: To improve the robustness of deep learning-based glioblastoma segmentation in a clinical setting with sparsified datasets.

Materials And Methods: In this retrospective study, preoperative T1-weighted, T2-weighted, T2-weighted fluid-attenuated inversion recovery, and postcontrast T1-weighted MRI from 117 patients (median age, 64 years; interquartile range [IQR], 55-73 years; 76 men) included within the Multimodal Brain Tumor Image Segmentation (BraTS) dataset plus a clinical dataset (2012-2013) with similar imaging modalities of 634 patients (median age, 59 years; IQR, 49-69 years; 382 men) with glioblastoma from six hospitals were used. Expert tumor delineations on the postcontrast images were available, but for various clinical datasets, one or more sequences were missing. The convolutional neural network, DeepMedic, was trained on combinations of complete and incomplete data with and without site-specific data. Sparsified training was introduced, which randomly simulated missing sequences during training. The effects of sparsified training and center-specific training were tested using Wilcoxon signed rank tests for paired measurements.

Results: A model trained exclusively on BraTS data reached a median Dice score of 0.81 for segmentation on BraTS test data but only 0.49 on the clinical data. Sparsified training improved performance (adjusted < .05), even when excluding test data with missing sequences, to median Dice score of 0.67. Inclusion of site-specific data during sparsified training led to higher model performance Dice scores greater than 0.8, on par with a model based on all complete and incomplete data. For the model using BraTS and clinical training data, inclusion of site-specific data or sparsified training was of no consequence.

Conclusion: Accurate and automatic segmentation of glioblastoma on clinical scans is feasible using a model based on large, heterogeneous, and partially incomplete datasets. Sparsified training may boost the performance of a smaller model based on public and site-specific data.Published under a CC BY 4.0 license.
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http://dx.doi.org/10.1148/ryai.2020190103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8082349PMC
September 2020

LAG-3 expression in the inflammatory microenvironment of glioma.

J Neurooncol 2021 May 2;152(3):533-539. Epub 2021 Mar 2.

Division of Oncology and Christian Doppler Laboratory for Personalized Immunotherapy, Department of Medicine I, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.

Purpose: Immune modulatory therapies including immune checkpoint inhibitors have so far failed to result in clinically meaningful efficacy in glioma. We aimed to investigate lymphocyte activation gene 3 (LAG-3), an inhibitory receptor on immune cells and target of second-generation immune checkpoint inhibitors, in glioma.

Methods: 97 patients with diffuse glioma (68 with glioblastoma, 29 with WHO grade II-III glioma) were identified from the Neuro-Biobank of the Medical University of Vienna. LAG-3 expression in the inflammatory microenvironment was assessed by immunohistochemistry (monoclonal anti-LAG-3 antibody, clone 17B4) and correlated to CD3+ , CD8+ , CD20+ and PD-1+ tumor-infiltrating lymphocytes (TILs) and PD-L1 expression on tumor cells.

Results: LAG-3+ TILs could be observed in 10/97 (10.3%) IDH-wildtype samples and in none of the included IDH-mutant glioma samples (p = 0.057). Further, LAG-3+ TILs were only observed in WHO grade IV glioblastoma, while none of the investigated WHO grade II-III glioma presented with LAG-3+ TILs (p = 0.03). No association of O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation and presence of LAG-3+ TILs was observed (p = 0.726). LAG-3 expression was associated with the presence of CD3+ (p = 0.029), CD8+ (p = 0.001), PD-1+ (p < 0.001) TILs and PD-L1+ tumor cells (p = 0.021), respectively. No association of overall survival with LAG-3+ TIL infiltration was evident (median OS 9.9 vs. 14.2 months, p = 0.95).

Conclusions: LAG-3 is only rarely expressed on TILs in IDH-wildtype glioma and associated with active inflammatory milieu as defined by higher TIL density. Immune microenvironment diversity should be considered in the design of future immunotherapy trials in glioma.
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http://dx.doi.org/10.1007/s11060-021-03721-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8084780PMC
May 2021

Heme Biosynthesis mRNA Expression Signature: Towards a Novel Prognostic Biomarker in Patients with Diffusely Infiltrating Gliomas.

Cancers (Basel) 2021 Feb 7;13(4). Epub 2021 Feb 7.

Department of Neurosurgery, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria.

Diffusely infiltrating gliomas are characterized by a variable clinical course, and thus novel prognostic biomarkers are needed. The heme biosynthesis cycle constitutes a fundamental metabolic pathway and might play a crucial role in glioma biology. The aim of this study was thus to investigate the role of the heme biosynthesis mRNA expression signature on prognosis in a large glioma patient cohort. Glioma patients with available sequencing data on heme biosynthesis expression were retrieved from The Cancer Genome Atlas (TCGA). In each patient, the heme biosynthesis mRNA expression signature was calculated and categorized into low, medium, and high expression subgroups. Differences in progression-free and overall survival between these subgroups were investigated including a multivariate analysis correcting for WHO grade, tumor subtype, and patient age and sex. In a total of 693 patients, progression-free and overall survival showed a strictly monotonical decrease with increasing mRNA expression signature subgroups. In detail, median overall survival was 134.2 months in the low, 79.9 months in the intermediate, and 16.5 months in the high mRNA expression signature subgroups, respectively. The impact of mRNA expression signature on progression-free and overall survival was independent of the other analyzed prognostic factors. Our data indicate that the heme biosynthesis mRNA expression signature might serve as an additional novel prognostic marker in patients with diffusely infiltrating gliomas to optimize postoperative management.
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http://dx.doi.org/10.3390/cancers13040662DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7916021PMC
February 2021

Prognostic Value of 5-ALA Fluorescence, Tumor Cell Infiltration and Angiogenesis in the Peritumoral Brain Tissue of Brain Metastases.

Cancers (Basel) 2021 Feb 3;13(4). Epub 2021 Feb 3.

Department of Neurosurgery, Medical University Vienna, Vienna General Hospital, Waehringer Guertel 18-20, 1090 Vienna, Austria.

Complete resection is an indispensable treatment option in the management of brain metastases (BM). 5-aminolevulinic acid (5-ALA) fluorescence is used for improved intraoperative visualization of tumor tissue in gliomas and was recently observed in BM. We investigated the potential of 5-ALA fluorescence to visualize the infiltrative growth of BM in the peritumoral brain tissue and its histopathological correlate. Patients with BM resection after 5-ALA administration and collection of tissue samples from peritumoral brain tissue were included. Each tissue sample was histopathologically investigated for tumor cell infiltration and angiogenesis. Altogether, 88 samples were collected from the peritumoral brain tissue in 58 BM of 55 patients. Visible 5-ALA fluorescence was found in 61 (69%) of the samples, tumor infiltration in 19 (22%) and angiogenesis in 13 (15%) of samples. Angiogenesis showed a significant correlation with presence of fluorescence ( = 0.008). Moreover, angiogenesis was related to visible 5-ALA fluorescence and showed an association with patient prognosis since it was significantly correlated to shorter time to local progression/recurrence ( = 0.001) and lower one-year survival ( = 0.031). Consequently, angiogenesis in the peritumoral brain tissue of BM might be a novel prognostic marker for individualized perioperative treatment concepts in the future.
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http://dx.doi.org/10.3390/cancers13040603DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7913757PMC
February 2021

Evaluation of the Temporal Muscle Thickness as an Independent Prognostic Biomarker in Patients with Primary Central Nervous System Lymphoma.

Cancers (Basel) 2021 Feb 2;13(3). Epub 2021 Feb 2.

Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, 1090 Vienna, Austria.

In this study, we assessed the prognostic relevance of temporal muscle thickness (TMT), likely reflecting patient's frailty, in patients with primary central nervous system lymphoma (PCNSL). In 128 newly diagnosed PCNSL patients TMT was analyzed on cranial magnetic resonance images. Predefined sex-specific TMT cutoff values were used to categorize the patient cohort. Survival analyses, using a log-rank test as well as Cox models adjusted for further prognostic parameters, were performed. The risk of death was significantly increased for PCNSL patients with reduced muscle thickness (hazard ratio of 3.189, 95% CI: 2-097-4.848, < 0.001). Importantly, the results confirmed that TMT could be used as an independent prognostic marker upon multivariate Cox modeling (hazard ratio of 2.504, 95% CI: 1.608-3.911, < 0.001) adjusting for sex, age at time of diagnosis, deep brain involvement of the PCNSL lesions, Eastern Cooperative Oncology Group (ECOG) performance status, and methotrexate-based chemotherapy. A TMT value below the sex-related cutoff value at the time of diagnosis is an independent adverse marker in patients with PCNSL. Thus, our results suggest the systematic inclusion of TMT in further translational and clinical studies designed to help validate its role as a prognostic biomarker.
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http://dx.doi.org/10.3390/cancers13030566DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7867149PMC
February 2021

5-ALA fluorescence for intraoperative visualization of spinal ependymal tumors and identification of unexpected residual tumor tissue: experience in 31 patients.

J Neurosurg Spine 2020 Dec 4:1-9. Epub 2020 Dec 4.

1Department of Neurosurgery.

Objective: Gross-total resection (GTR) is the treatment of choice in the majority of patients suffering from spinal ependymal tumors. In such tumors, the extent of resection (EOR) is considered the key factor for tumor recurrence and thus patient prognosis. However, incomplete resection is not uncommon and leads to increased risk of tumor recurrence. One important cause of incomplete resection is insufficient intraoperative visualization of tumor tissue as well as residual tumor tissue. Therefore, the authors investigated the value of 5-aminolevulinic acid (5-ALA)-induced fluorescence in a series of spinal ependymal tumors for improved tumor visualization.

Methods: Adult patients who underwent preoperative 5-ALA administration and surgery for a spinal ependymal tumor were included in this study. For each tumor, a conventional white-light microsurgical resection was performed. Additionally, the fluorescence status (strong, vague, or no fluorescence) and fluorescence homogeneity (homogenous or inhomogeneous) of the spinal ependymal tumors were evaluated during surgery using a modified neurosurgical microscope. In intramedullary tumor cases with assumed GTR, the resection cavity was investigated for potential residual fluorescing foci under white-light microscopy. In cases with residual fluorescing foci, these areas were safely resected and the corresponding samples were histopathologically screened for the presence of tumor tissue.

Results: In total, 31 spinal ependymal tumors, including 27 intramedullary tumors and 4 intradural extramedullary tumors, were included in this study. Visible fluorescence was observed in the majority of spinal ependymal tumors (n = 25, 81%). Of those, strong fluorescence was noted in 23 of these cases (92%), whereas vague fluorescence was present in 2 cases (8%). In contrast, no fluorescence was observed in the remaining 6 tumors (19%). Most ependymal tumors demonstrated an inhomogeneous fluorescence effect (17 of 25 cases, 68%). After assumed GTR in intramedullary tumors (n = 15), unexpected residual fluorescing foci within the resection cavity could be detected in 5 tumors (33%). These residual fluorescing foci histopathologically corresponded to residual tumor tissue in all cases.

Conclusions: This study indicates that 5-ALA fluorescence makes it possible to visualize the majority of spinal ependymal tumors during surgery. Unexpected residual tumor tissue could be detected with the assistance of 5-ALA fluorescence in approximately one-third of analyzed intramedullary tumors. Thus, 5-ALA fluorescence might be useful to increase the EOR, particularly in intramedullary ependymal tumors, in order to reduce the risk of tumor recurrence.
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http://dx.doi.org/10.3171/2020.6.SPINE20506DOI Listing
December 2020

Macroscopic fluorescence-lifetime imaging of NADH and protoporphyrin IX improves the detection and grading of 5-aminolevulinic acid-stained brain tumors.

Sci Rep 2020 11 24;10(1):20492. Epub 2020 Nov 24.

Department of Neurosurgery, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.

Maximal safe tumor resection remains the key prognostic factor for improved prognosis in brain tumor patients. Despite 5-aminolevulinic acid-based fluorescence guidance the neurosurgeon is, however, not able to visualize most low-grade gliomas (LGG) and infiltration zone of high-grade gliomas (HGG). To overcome the need for a more sensitive visualization, we investigated the potential of macroscopic, wide-field fluorescence lifetime imaging of nicotinamide adenine dinucleotide (NADH) and protoporphyrin IX (PPIX) in selected human brain tumors. For future intraoperative use, the imaging system offered a square field of view of 11 mm at 250 mm free working distance. We performed imaging of tumor tissue ex vivo, including LGG and HGG as well as brain metastases obtained from 21 patients undergoing fluorescence-guided surgery. Half of all samples showed visible fluorescence during surgery, which was associated with significant increase in PPIX fluorescence lifetime. While the PPIX lifetime was significantly different between specific tumor tissue types, the NADH lifetimes did not differ significantly among them. However, mainly necrotic areas exhibited significantly lower NADH lifetimes compared to compact tumor in HGG. Our pilot study indicates that combined fluorescence lifetime imaging of NADH/PPIX represents a sensitive tool to visualize brain tumor tissue not detectable with conventional 5-ALA fluorescence.
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http://dx.doi.org/10.1038/s41598-020-77268-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7686506PMC
November 2020

Soluble PD-L1 is associated with local and systemic inflammation markers in primary and secondary brain tumours.

ESMO Open 2020 11;5(6):e000863

Department of Medicine I, Division of Oncology, Medical University of Vienna, Vienna, Austria. Electronic address:

Background: Immune-modulatory treatments have so far shown limited clinical activity in primary brain tumours. We aimed to investigate soluble programmed death receptor ligand 1 (sPD-L1) as systemic inflammation parameter in patients with brain tumour.

Methods: EDTA plasma was collected from 81 glioma (55 glioblastoma (GBM), 26 lower-grade glioma (LGG)), 17 meningioma and 44 brain metastasis (BM) patients and 24 controls. sPD-L1 concentrations were determined by ELISA. Correlations with the local tumour microenvironment were assessed by immunohistochemical analysis for PD-L1, CD3 and CD8.

Results: sPD-L1 was detected in 62 out of 166 (37.7%) patients (glioma: 41/81, 50.6%; meningioma: 5/17, 29.4%; BM: 7/44, 15.9%; controls: 9/24, 37.5%; p=0.002). sPD-L1 concentrations were lower in BM than in LGG (p=0.003) or GBM (p<0.001). Membranous PD-L1 expression on tumour cells was not associated with sPD-L1 concentrations (p=0.953). sPD-L1 concentration was inversely correlated with the density of CD8+ (r=-0.713, p=0.001) and CD3+ (r=-0.484, p=0.042) tumour-infiltrating lymphocytes in LGG. sPD-L1 is correlated with neutrophil counts (r=-0.318, p=0.045) and C reactive protein levels (r=-0.363, p=0.008) in GBM. sPD-L1+ patients had longer overall survival in GBM (p=0.006) and worse OS in LGG (p=0.028).

Conclusions: sPD-L1 is detectable in a fraction of patients with brain tumour. Although it is not correlated with tissue PD-L1 expression, correlations with other local and systemic inflammation parameters could be detected in LGG and GBM.
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http://dx.doi.org/10.1136/esmoopen-2020-000863DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7662140PMC
November 2020

Distributed changes of the functional connectome in patients with glioblastoma.

Sci Rep 2020 10 27;10(1):18312. Epub 2020 Oct 27.

Computational Imaging Research Lab, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Spitalgasse 23, 1090, Vienna, Austria.

Glioblastoma might have widespread effects on the neural organization and cognitive function, and even focal lesions may be associated with distributed functional alterations. However, functional changes do not necessarily follow obvious anatomical patterns and the current understanding of this interrelation is limited. In this study, we used resting-state functional magnetic resonance imaging to evaluate changes in global functional connectivity patterns in 15 patients with glioblastoma. For six patients we followed longitudinal trajectories of their functional connectome and structural tumour evolution using bi-monthly follow-up scans throughout treatment and disease progression. In all patients, unilateral tumour lesions were associated with inter-hemispherically symmetric network alterations, and functional proximity of tumour location was stronger linked to distributed network deterioration than anatomical distance. In the longitudinal subcohort of six patients, we observed patterns of network alterations with initial transient deterioration followed by recovery at first follow-up, and local network deterioration to precede structural tumour recurrence by two months. In summary, the impact of focal glioblastoma lesions on the functional connectome is global and linked to functional proximity rather than anatomical distance to tumour regions. Our findings further suggest a relevance for functional network trajectories as a possible means supporting early detection of tumour recurrence.
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http://dx.doi.org/10.1038/s41598-020-74726-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7591862PMC
October 2020

High-resolution metabolic imaging of high-grade gliomas using 7T-CRT-FID-MRSI.

Neuroimage Clin 2020 15;28:102433. Epub 2020 Sep 15.

High-field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.

Objectives: Successful neurosurgical intervention in gliomas depends on the precision of the preoperative definition of the tumor and its margins since a safe maximum resection translates into a better patient outcome. Metabolic high-resolution imaging might result in improved presurgical tumor characterization, and thus optimized glioma resection. To this end, we validated the performance of a fast high-resolution whole-brain 3D-magnetic resonance spectroscopic imaging (MRSI) method at 7T in a patient cohort of 23 high-grade gliomas (HGG).

Materials And Methods: We preoperatively measured 23 patients with histologically verified HGGs (17 male, 8 female, age 53 ± 15) with an MRSI sequence based on concentric ring trajectories with a 64 × 64 × 39 measurement matrix, and a 3.4 × 3.4 × 3.4 mm nominal voxel volume in 15 min. Quantification used a basis-set of 17 components including N-acetyl-aspartate (NAA), total choline (tCho), total creatine (tCr), glutamate (Glu), glutamine (Gln), glycine (Gly) and 2-hydroxyglutarate (2HG). The resultant metabolic images were evaluated for their reliability as well as their quality and compared to spatially segmented tumor regions-of-interest (necrosis, contrast-enhanced, non-contrast enhanced + edema, peritumoral) based on clinical data and also compared to histopathology (e.g., grade, IDH-status).

Results: Eighteen of the patient measurements were considered usable. In these patients, ten metabolites were quantified with acceptable quality. Gln, Gly, and tCho were increased and NAA and tCr decreased in nearly all tumor regions, with other metabolites such as serine, showing mixed trends. Overall, there was a reliable characterization of metabolic tumor areas. We also found heterogeneity in the metabolic images often continued into the peritumoral region. While 2HG could not be satisfyingly quantified, we found an increase of Glu in the contrast-enhancing region of IDH-wildtype HGGs and a decrease of Glu in IDH1-mutant HGGs.

Conclusions: We successfully demonstrated high-resolution 7T 3D-MRSI in HGG patients, showing metabolic differences between tumor regions and peritumoral tissue for multiple metabolites. Increases of tCho, Gln (related to tumor metabolism), Gly (related to tumor proliferation), as well as decreases in NAA, tCr, and others, corresponded very well to clinical tumor segmentation, but were more heterogeneous and often extended into the peritumoral region.
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http://dx.doi.org/10.1016/j.nicl.2020.102433DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7511769PMC
June 2021

Postoperative Magnetic Resonance Imaging After Surgery of Brain Metastases: Analysis of Extent of Resection and Potential Risk Factors for Incomplete Resection.

World Neurosurg 2020 11 27;143:e365-e373. Epub 2020 Jul 27.

Department of Neurosurgery, Medical University Vienna, Vienna, Austria; Comprehensive Cancer Center, Medical University Vienna, Vienna, Austria. Electronic address:

Background: Extent of resection (EOR) constitutes a crucial factor for patient prognosis in surgery of brain metastases (BMs). According to early studies using postoperative magnetic resonance imaging (MRI), an unexpected residual tumor was not uncommon. Knowledge of potential risk factors for incomplete BM resection would be of major importance to optimize surgical strategies. The aim of this study was to evaluate EOR in a large cohort and analyze potential risk factors for incomplete BM resection.

Methods: Patients with BM resection and available postoperative MRI were included. Intraoperative estimation of EOR by the neurosurgeon was noted. Additionally, EOR was determined by postoperative MRI. Potential risk factors for incomplete resection were investigated.

Results: There were 145 patients with 163 BMs included. According to postoperative MRI, complete resection was achieved in 103 (63%) BMs, and resection was incomplete in 44 (27%) BMs. Postoperative MRI detected unexpected residual tumor in 32 (25%) BMs, and a misjudgment of the EOR by the neurosurgeon was found in 29% of cases. Regarding risk factors for incomplete resection, preoperative tumor volume was significantly larger in incompletely resected BMs compared with completely resected BMs (P = 0.011). All other analyzed risk factors had no significant influence on EOR.

Conclusions: Our data indicate that postoperative MRI is able to detect a high portion of unexpected residual tumors after surgery of BMs. Preoperative tumor volume in particular represents an important risk factor for incomplete resection, and hence neurosurgeons should pay special attention to avoid residual tumor tissue.
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http://dx.doi.org/10.1016/j.wneu.2020.07.150DOI Listing
November 2020

TCGA mRNA Expression Analysis of the Heme Biosynthesis Pathway in Diffusely Infiltrating Gliomas: A Comparison of Typically 5-ALA Fluorescent and Non-Fluorescent Gliomas.

Cancers (Basel) 2020 Jul 24;12(8). Epub 2020 Jul 24.

Department of Neurosurgery, Medical University Vienna, 1090 Vienna, Austria.

5-Aminolevulinic acid (5-ALA) is a fluorescent dye that after metabolization to Protoporphyrin IX (PpIX) by the heme biosynthesis pathway typically leads to visible fluorescence in WHO grade IV but not grade II gliomas. The exact mechanism for high PpIX levels in WHO grade IV gliomas and low PpIX levels in WHO grade II gliomas is not fully clarified. To detect relevant changes in mRNA expression, we performed an in-silico analysis of WHO grade II and IV glioma sequencing datasets provided by The Cancer Genome Atlas (TCGA) to investigate mRNA expression levels of relevant heme biosynthesis genes: Solute Carrier Family 15 Member 1 and 2 (SLC15A1 and SLC15A2), Aminolevulinate-Dehydratase (ALAD), Hydroxymethylbilane-Synthase (HMBS), Uroporphyrinogen-III-Synthase (UROS), Uroporphyrinogen-Decarboxylase (UROD), Coproporphyrinogen-Oxidase (CPOX), Protoporphyrinogen-Oxidase (PPOX), ATP-binding Cassette Subfamily B Member 6 (ABCB6)/G Member 2 (ABCG2) and Ferrochelatase (FECH). Altogether, 258 WHO grade II and 166 WHO grade IV samples were investigated. The mRNA expression levels showed significant differences in 8 of 11 examined genes between WHO grade II and IV gliomas. Significant differences in mRNA expression included increases of HMBS, UROD, FECH and PPOX as well as decreases of SLC15A2, ALAD, UROS and ABCB6 in WHO IV gliomas. Since the majority of changes was found in directions that might actually impair PpIX accumulation in WHO grade IV gliomas, additional studies are needed to analyze the corresponding factors of the heme biosynthesis also on protein level.
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http://dx.doi.org/10.3390/cancers12082043DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7466145PMC
July 2020

Improved Diagnostic Imaging of Brain Tumors by Multimodal Microscopy and Deep Learning.

Cancers (Basel) 2020 Jul 6;12(7). Epub 2020 Jul 6.

Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, 1090 Vienna, Austria.

Fluorescence-guided surgery is a state-of-the-art approach for intraoperative imaging during neurosurgical removal of tumor tissue. While the visualization of high-grade gliomas is reliable, lower grade glioma often lack visible fluorescence signals. Here, we present a hybrid prototype combining visible light optical coherence microscopy (OCM) and high-resolution fluorescence imaging for assessment of brain tumor samples acquired by 5-aminolevulinic acid (5-ALA) fluorescence-guided surgery. OCM provides high-resolution information of the inherent tissue scattering and absorption properties of tissue. We here explore quantitative attenuation coefficients derived from volumetric OCM intensity data and quantitative high-resolution 5-ALA fluorescence as potential biomarkers for tissue malignancy including otherwise difficult-to-assess low-grade glioma. We validate our findings against the gold standard histology and use attenuation and fluorescence intensity measures to differentiate between tumor core, infiltrative zone and adjacent brain tissue. Using large field-of-view scans acquired by a near-infrared swept-source optical coherence tomography setup, we provide initial assessments of tumor heterogeneity. Finally, we use cross-sectional OCM images to train a convolutional neural network that discriminates tumor from non-tumor tissue with an accuracy of 97%. Collectively, the present hybrid approach offers potential to translate into an in vivo imaging setup for substantially improved intraoperative guidance of brain tumor surgeries.
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http://dx.doi.org/10.3390/cancers12071806DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7408054PMC
July 2020

High Diagnostic Accuracy of Visible 5-ALA Fluorescence in Meningioma Surgery According to Histopathological Analysis of Tumor Bulk and Peritumoral Tissue.

Lasers Surg Med 2021 03 1;53(3):300-308. Epub 2020 Jul 1.

Department of Neurosurgery, Medical University Vienna, Waehringer Gürtel 18-20, Vienna, 1090, Austria.

Background And Objectives: Complete neurosurgical resection of intracranial meningiomas is essential to avoid residual tumor tissue and thus minimize the risk of tumor recurrence. However, local recurrence of meningiomas is not uncommon mainly due to insufficient intraoperative detection of residual tumor tissue within the tumor bulk or peritumoral tissue such as bone and satellite lesions. Although 5-aminolevulinic acid (5-ALA) induced fluorescence was found to visualize the majority of meningiomas, no comprehensive histopathological assessment of fluorescing samples from the tumor bulk and peritumoral tissue is available. The aim of our study was thus to histopathologically analyze a large series of tissue samples derived from meningioma surgery to assess the positive predictive value (PPV) of visible 5-ALA fluorescence.

Study Design/materials And Methods: In this study, we retrospectively investigated a series of tissue samples with visible 5-ALA fluorescence collected during surgery of intracranial meningiomas from the tumor bulk and peritumoral tissue including the bone flap, dura/dural tail, arachnoidea, adjacent cortex, and satellite lesions. The tumor diagnosis was established according to the World Health Organization (WHO) criteria and all collected fluorescing samples were screened for presence of tumor tissue to calculate the PPV.

Results: Altogether, 191 tissue samples with visible 5-ALA fluorescence derived during surgery of 85 meningiomas (63 WHO grade I, 17 WHO grade II, and 5 WHO grade III) were included. In detail, 158 samples from the tumor bulk and 33 specimens from the peritumoral tissue were investigated. According to histopathological analysis, the PPV of 5-ALA fluorescence was significantly higher in samples from the tumor bulk (100%) as compared with peritumoral tissue (73%; P < 0.001). With regard to peritumoral tissue, tumor tissue was present in most fluorescing samples from the satellite lesions (100%), the bone flap (92%), arachnoidea (83%), and dura/dural tail (75%). In contrast, tumor tissue was absent in the majority of samples from fluorescing cortex (six of seven samples; 86%). However, distinct reactive tissue alterations were found in all six tumor-free fluorescing cortex samples and additional vascular proliferation in two cases.

Conclusion: In this largest series to date, visible 5-ALA fluorescence is characterized by a high PPV detecting tumor bulk and peritumoral tissue in intracranial meningiomas. Thus, 5-ALA fluorescence supports the neurosurgeon in identifying residual tumor tissue at relevant surgical sites to optimize meningioma surgery and minimize the risk of local recurrence. © 2020 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals LLC.
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http://dx.doi.org/10.1002/lsm.23294DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8048546PMC
March 2021

Perioperative imaging in patients treated with resection of brain metastases: a survey by the European Association of Neuro-Oncology (EANO) Youngsters committee.

BMC Cancer 2020 May 12;20(1):410. Epub 2020 May 12.

Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.

Background: Neurosurgical resection represents an important treatment option in the modern, multimodal therapy approach of brain metastases (BM). Guidelines for perioperative imaging exist for primary brain tumors to guide postsurgical treatment. Optimal perioperative imaging of BM patients is so far a matter of debate as no structured guidelines exist.

Methods: A comprehensive questionnaire about perioperative imaging was designed by the European Association of Neuro-Oncology (EANO) Youngsters Committee. The survey was distributed to physicians via the EANO network to perform a descriptive overview on the current habits and their variability on perioperative imaging. Chi square test was used for dichotomous variables.

Results: One hundred twenty physicians worldwide responded to the survey. MRI was the preferred preoperative imaging method (93.3%). Overall 106/120 (88.3%) physicians performed postsurgical imaging routinely including MRI alone (62/120 [51.7%]), postoperative CT (29/120 [24.2%]) and MRI + CT (15/120 [12.5%]). No correlation of postsurgical MRI utilization in academic vs. non-academic hospitals (58/89 [65.2%] vs. 19/31 [61.3%], p = 0.698) was found. Early postoperative MRI within ≤72 h after resection is obtained by 60.8% of the participants. The most frequent reason for postsurgical imaging was to evaluate the extent of tumor resection (73/120 [60.8%]). In case of residual tumor, 32/120 (26.7%) participants indicated to adjust radiotherapy, 34/120 (28.3%) to consider re-surgery to achieve complete resection and 8/120 (6.7%) to evaluate both.

Conclusions: MRI was the preferred imaging method in the preoperative setting. In the postoperative course, imaging modalities and timing showed high variability. International guidelines for perioperative imaging with special focus on postoperative MRI to assess residual tumor are warranted to optimize standardized management and adjuvant treatment decisions for BM patients.
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http://dx.doi.org/10.1186/s12885-020-06897-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7216695PMC
May 2020
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