Non-invasive prediction of IDH-wildtype genotype in gliomas using dynamic 18F-FET PET.

PURPOSE: According to the updated WHO classification of gliomas with its emphasis on molecular parameters, tumours with an IDH-wildtype status have a dismal prognosis. To ensure timely adjustment of treatment, demand for non-invasive prediction methods is high. 18F-FET PET has been shown to be an important diagnostic tool for glioma management. The aim of this study was to assess the value of dynamic 18F-FET PET for the non-invasive prediction of the IDH-mutation status. METHODS: Newly diagnosed WHO grade II-IV glioma patients with MRI and dynamic 18F-FET PET were included. The 18F-FET PET parameters mean and maximal tumour-to-background ratio (TBRmean, TBRmax) and minimal time-to-peak (TTPmin) were evaluated. The diagnostic power for the prediction of the IDH genotype (positive/negative predictive value) was tested in the overall study group and in the subgroup of non-contrast enhancing gliomas. RESULTS: Three hundred forty-one patients were evaluated. Molecular analyses revealed 178 IDH-mutant and 163 IDH-wildtype tumours. Overall, 270/341 gliomas were classified as 18F-FET-positive (TBRmax > 1.6), 90.2% of the IDH-wildtype and 69.1% of IDH-mutant gliomas. Median TBRmax was significantly higher in IDH-wildtype compared with IDH-mutant gliomas (2.9 vs. 2.3, p < 0.001); however, ROC-analyses revealed no reliable cutoff due to a high overlap (range 1.0-7.1 vs. 1.1-7.9). Dynamic analysis revealed a significantly shorter TTPmin in IDH-wildtype gliomas; using TTPmin ≤ 12.5 min as indicator for IDH-wildtype gliomas, a positive predictive value of 87% was reached (negative predictive value 72%, AUC = 0.796, p ≤ 0.001). A total of 161/341 gliomas did not show contrast enhancement on MRI; even within this subgroup, TTPmin ≤ 12.5 min remained a good predictor of IDH-wildtype glioma (positive predictive value 83%, negative predictive value 90%; AUC = 0.868, p < 0.001). CONCLUSION: A short TTPmin in dynamic 18F-FET PET serves as good predictor of highly aggressive IDH-wildtype status in gliomas. In particular, a high diagnostic power was observed in the subgroup of non-contrast enhancing gliomas, which helps to identify patients with worse prognosis.

Radiation dose and image quality in intraoperative CT (iCT) angiography of the brain with stereotactic head frames.

OBJECTIVES: Intraoperative CT (iCT) angiography of the brain with stereotactic frames is an integral part of navigated neurosurgery. Validated data regarding radiation dose and image quality in these special examinations are not available. We therefore investigated two iCT protocols in this IRB-approved study. METHODS: Retrospective analysis of patients, who received a cerebral stereotactic iCT angiography on a 128 slice CT scanner between February 2016 and December 2017. In group A, automated tube current modulation (ATCM; reference value 410 mAs) and automated tube voltage selection (reference value 120 kV) were enabled, and only examinations with a selected voltage of 120 kV were included. In group B, fixed parameters were applied (300 mAs, 120 kV). Radiation dose was measured by assessing the volumetric CT dose index (CTDIvol), dose length product (DLP) and effective dose (ED). Signal-to-noise ratio (SNR) and image noise were assessed for objective image quality, visibility of arteries and grey-white differentiation for subjective image quality. RESULTS: Two hundred patients (n = 100 in each group) were included. In group A, median selected tube current was 643 mAs (group B, 300 mAs; p < 0.001). Median values of CTDIvol, DLP and ED were 91.54 mGy, 1561 mGy cm and 2.97 mSv in group A, and 43.15 mGy, 769 mGy cm and 1.46 mSv in group B (p < 0.001). Image quality did not significantly differ between groups (p > 0.05). CONCLUSIONS: ATCM yielded disproportionally high radiation dose due to substantial tube current increase at the frame level, while image quality did not improve. Thus, ATCM should preferentially be disabled. KEY POINTS: • Automated tube current modulation (ATCM) yields disproportionally high radiation dose in intraoperative CT angiography of the brain with stereotactic head frames. • ATCM does not improve overall image quality in these special examinations. • ATCM is not yet optimised for CT angiography of the brain with major extracorporeal foreign materials within the scan range.

18F-FET-PET as a biomarker for therapy response in non-contrast enhancing glioma following chemotherapy.

BACKGROUND: Monitoring treatment response after chemotherapy of gadolinium-(Gd)-negative gliomas is challenging as conventional MRI often indicates no radiological changes. We hypothesize that 18F-FET-PET can be used as a biomarker for response assessment in Gd-negative gliomas undergoing chemotherapy. METHODS: Sixty-one patients harboring Gd-negative WHO grade II or III glioma receiving alkylating agents (temozolomide or CCNU/procarbacine) were included. All patients underwent MRI and 18F-FET-PET before chemotherapy and 6 months later. We calculated T2-volume, 18F-FET-PET based biological tumour volume (BTV) and maximal tumour-to-brain ratio (TBRmax). Moreover, dynamic PET acquisition was performed using time-activity-curves (TACs) analysis. For MRI-based response assessment, RANO criteria for low-grade glioma were used. For 18F-FET-PET, following classification scheme was tested: responsive disease (RD) when a decrease in either BTV ≥ 25% and/or TBRmax ≥ 10% occurred, an increase in BTV ≥ 25% and/or TBRmax increase > 10% characterized progressive disease (PD), minor changes ± 25% for BTV and ± 10% for TBRmax were regarded as stable disease (SD). Post-chemotherapy survival (PCS) and time-to-treatment failure (TTF) were calculated using the Kaplan-Meier method. RESULTS: 18F-FET-PET based response has shown patients with RD to have the longest TTF time (78.5 vs 24.6 vs 24.1 months, p = 0.001), while there was no significant difference between patients with a SD and PD. A comparable pattern was observed for PCS (p < 0.001). T2-volume based assessment was not associated with outcome. CONCLUSION: 18F-FET-PET is a promising biomarker for early response assessment in Gd-negative gliomas undergoing chemotherapy. It might be helpful for a timely adjustment of potentially ineffective treatment concepts and overcomes limitations of conventional structural imaging.

Iodine-125 brachytherapy as upfront and salvage treatment for brain metastases : A comparative analysis.

BACKGROUND: Outcome and toxicity profiles of salvage stereotactic ablative radiation strategies for recurrent pre-irradiated brain metastases are poorly defined. This study compared risk-benefit profiles of upfront and salvage iodine-125 brachytherapy (SBT) for small brain metastases. As the applied SBT treatment algorithm required histologic proof of metastatic brain disease in all patients, we additionally aimed to elucidate the value of biopsy before SBT. PATIENTS AND METHODS: Patients with small untreated (n = 20) or pre-irradiated (n =28) suspected metastases intended for upfront or salvage SBT, respectively, were consecutively included. Temporary iodine-125 implants were used (median reference dose: 50 Gy, median dose rate: 15 cGy/h). Cumulative biologically effective doses (BED) were calculated and used for risk assessment. Treatment toxicity was classified according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) criteria. RESULTS: Upfront SBT was initiated in 20 patients and salvage SBT in 23. In 5 patients, salvage SBT was withheld because of proven radiation-induced lesions. Treatment groups exhibited similar epidemiologic data except for tumor size (which was slightly smaller in the salvage group). One-year local/distant tumor control rates after upfront and salvage SBT were similar (94 %/65 % vs. 87 %/57 %, p = 0.45, respectively). Grade I/II toxicity was suffered by 2 patients after salvage SBT (cumulative BED: 192.1 Gy3 and 249.6 Gy3). No toxicity-related risk factors were identified. CONCLUSION: SBT combines diagnostic yield with effective treatment in selected patients. The low toxicity rate in the salvage group points to protective radiobiologic characteristics of continuous low-dose rate irradiation. Upfront and salvage SBT are similarly effective and safe. Histologic reevaluation should be reconsidered after previous radiotherapy to avoid under- or overtreatment.

Re-irradiation strategies in combination with bevacizumab for recurrent malignant glioma.

The place of bevacizumab (BEV) in salvage re-irradiation (Re-RT) settings of malignant glioma is poorly defined. In the current study risk/benefit profiles of two BEV-based Re-RT protocols were analyzed and compared with that of salvage BEV plus irinotecan (BEV/IRI). According to interdisciplinary tumor board recommendations, patients were assigned to one of three BEV-based treatment protocols: (1) BEV/IRI, (2) Re-RT (36 Gy/18 fx) with concomitant BEV (Re-RT/BEV), and (3) Re-RT with concomitant/maintenance BEV (Re-RT/BEV→BEV). Prognostic factors were obtained from proportional hazards models. Adverse events were classified according to the NCI CTCAE, v4.0. 105 consecutive patients were enrolled from 08/2008 to 05/2014. Patients undergoing Re-RT experienced longer time intervals from initial diagnosis to BEV treatment (median: 22.0 months vs. 13.7 months, p = 0.001); those assigned to Re-RT/BEV→BEV rated better on the performance scale (median KPSREC: 90 vs. 70, p = 0.013). Post-recurrence survival after BEV-based treatment (PRS) was longest after Re-RT/BEV→BEV (median: 13.1 months vs. 8 months, p = 0.006). PRS after Re-RT/BEV and BEV/IRI was similar. Multivariately, higher KPSREC and Re-RT/BEV→BEV were associated with longer PRS. Treatment toxicity did not differ among groups. Re-RT/BEV→BEV is safe, feasible and effective and deserves further prospective evaluation.

Dynamic 18F-FET PET in suspected WHO grade II gliomas defines distinct biological subgroups with different clinical courses.

In suspected grade II gliomas, three distinct patterns of time-activity curves (TAC) on O-(2-[(18)F]fluoroethyl)-1-tyrosine ((18)F-FET) positron emission tomography (PET) have been delineated (i) increasing TAC homogeneously throughout the tumor, and decreasing TAC, (ii) either homogeneously throughout the tumor or (iii) only focally within otherwise increasing TAC patterns. Increasing TAC was associated with low-grade histology and decreasing TAC with high-grade histology. This prospective study analyzed whether these patterns correlate with distinct biological tumor subtypes and differential outcome. (18)F-FET PET-guided biopsies were used for stepwise histopathological evaluation. Molecular-genetic evaluation included O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation, isocitrate dehydrogenase (IDH1/2) mutational and 1p/19q codeletion status. Progression-free survival (PFS) was estimated with the Kaplan-Meier method. Prognostic factors were obtained from multivariate regression models. 98 adult patients were included. Homogeneous increasing, focal decreasing and homogeneous decreasing TAC were seen in 51, 19 and 28 patients. The corresponding 1-year (2-years) PFS were 92% (85%), 89% (51%) and 50% (28%; p = 0.002). IDH1/2 mutations were more frequent in tumors with homogeneous increasing (90%) and focal decreasing (79%) TAC, but were rare in those exhibiting homogeneous decreasing TAC (25%; p < 0.001). Overall, TAC patterns, IDH1/2 mutational and 1p/19q codeletion status were powerful and independent prognostic factors. Dynamic (18)F-FET PET might be an important and independent imaging biomarker for patients with suspected WHO grade II gliomas and offers perspectives for stratified diagnostic and therapeutic strategies. Tumors with focal decreasing TAC need highly targeted surgical interventions to avoid undergrading and undertreatment.

Outcome and toxicity profile of salvage low-dose-rate iodine-125 stereotactic brachytherapy in recurrent high-grade gliomas.

BACKGROUND: The aim of this study was to provide an outcome and toxicity profile of salvage low-dose-rate iodine-125 (I-125) stereotactic brachytherapy (SBT) in patients with small, circumscribed malignant glioma recurrences. METHODS: Patients with malignant glioma recurrences consecutively undergoing salvage SBT from 2003 to 2011 were identified from our prospective tumor database. SBT was considered a potentially suitable treatment strategy for adult mostly multimodally pretreated patients (Karnofsky score of ≥ 70) with biopsy-proven, circumscribed, small (diameter ≤ 3.5 cm) recurrences. Exclusively temporary I-125 seeds were used (reference dose: 50 Gy, dose rate: < 15 cGy/h). Study endpoints were time-to-treatment failure (TTF) after SBT, postrecurrence survival (PRS), and toxicity. Survival was assessed with the Kaplan-Meier method. Adverse events were categorized according to the RTOG/EORTC classification. Prognostic factors were obtained from proportional hazards models. RESULTS: Sixty-eight patients (28 WHO grade III, 40 WHO grade IV gliomas) were included. Fifty-nine patients had previously received external beam radiation. Median TTF and PRS were 8.3 months and 13.4 months, respectively. TTF and PRS were longer for grade III gliomas than for glioblastomas (15.0 vs. 6.2 months and 28.1 vs. 9.3 months, respectively). Patients with grade III tumors were younger (p = 0.002). Favorable factors for TTF and PRS were age ≤ 50 years and a methylated O(6)-methylguanine-DNA methyltransferase (MGMT)-promoter. Alternative models including tumor grade instead of age reached a similar good fit. Three patients suffered from grade I, one from grade II, and two from grade IV toxicity. CONCLUSIONS: Salvage SBT is feasible and safe even after previously performed external beam radiation. Favorable outcome measurements in particular for grade III recurrences deserve further prospective evaluation.

Re-irradiation and bevacizumab in recurrent high-grade glioma: an effective treatment option.

Re-irradiation has been shown to be a meaningful option for recurrent high-grade glioma (HGG) patients. Furthermore, bevacizumab exerts certain activity in combination with chemotherapy/as monotherapy and was safely tested in combination with radiotherapy in several previous studies. To our knowledge, this is the largest cohort of patients treated with both re-irradiation and bevacizumab to date. After receiving standard radiotherapy (with or without TMZ) patients with recurrent HGG were treated with bevacizumab (10 mg/kg intravenously at d1 and d15) during re-irradiation. Median prescribed radiation dose during re-treatment was 36 Gy, conventionally fractionated. Datasets of 71 re-irradiated patients were retrospectively analyzed. Patients either received bevacizumab (N = 57) or not (N = 14; other substances (N = 4) and sole radiation (N = 10)). In patients receiving bevacizumab, both post-recurrence survival (PRS) (median 8.6 vs. 5.7 months; p = 0.003, log-rank test) and post-recurrence progression-free survival (PR-PFS, 5.6 vs. 2.5 months; p = 0.005, log-rank test; PFS-6 42.1 % for the bevacizumab group) were significantly increased which was confirmed by multivariate analysis. KPS, re-surgery, MGMT methylation status, sex, WHO grade, tumor volume and age were no significant predictors for neither PR-PFS nor PRS (univariate analysis). Re-irradiation with bevacizumab remains a feasible and highly effective treatment schedule. Studies on further salvage strategies and timing of sequential treatment options versus observation are warranted.

Protoporphyrin IX fluorescence and photobleaching during interstitial photodynamic therapy of malignant gliomas for early treatment prognosis.

BACKGROUND AND OBJECTIVE: Interstitial photodynamic therapy (iPDT) of non-resectable recurrent glioblastoma using 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) has shown a promising outcome. It remained unclear, however, to what extent inter- and intra-tumoural differences of PpIX concentrations influence the efficacy of iPDT. In the current pilot study, we analysed PpIX concentrations quantitatively and assessed PpIX induced fluorescence and photobleaching intraoperatively. MATERIALS AND METHODS: Five patients harbouring non-resectable glioblastomas were included. ALA (20 or 30 mg/kg body weight) was given 5-8 hours before treatment. Stereotactic biopsies were taken throughout the tumour volume for both histological analysis and determination of PpIX concentrations, which were measured by chemical extraction. Cylindrical light diffusors were stereotactically implanted. Prior to and after irradiation, fluorescence measurements were performed. Outcome measurement was based on clinical and neuro-radiological follow up. RESULTS: In three patients, a strong PpIX fluorescence was seen before treatment, which was completely photobleached after iPDT. High concentrations of PpIX could be detected in viable tumour parts of these patients (mean PpIX uptake per tumour: 1.4-3.0 µM). In the other two patients, however, no or only low PpIX uptake (0-0.6 µM) could be detected. The patients with strong PpIX uptake showed treatment response and long-term clinical stabilisation (no progression in 29, 30 and 36 months), early treatment failure was seen in the remaining two patients (death after 3 and 9 months). CONCLUSIONS: Intra-tumoural PpIX concentrations exhibited pronounced inter- and intra-tumoural variations in glioblastoma, which are directly linked to variable degrees of fluorescence intensity. High intra-tumoural PpIX concentrations with strong fluorescence intensity and complete photobleaching after iPDT seem to be associated with favourable outcome. Real-time monitoring of PpIX fluorescence intensity and photobleaching turned out to be feasible and safe and might be employed for early treatment prognosis of iPDT.

IDH1 mutations in grade II astrocytomas are associated with unfavorable progression-free survival and prolonged postrecurrence survival.

BACKGROUND: The favorable prognostic impact of mutations in the IDH1 gene is well documented for malignant gliomas; its influence on World Health Organization (WHO) grade II astrocytomas, however, is still under debate. METHODS: A previously published database of 127 predominantly surgically treated patients harboring WHO grade II astrocytomas was revisited. Patients were screened for TP53 mutations (sequencing analysis), IDH1 mutations (pyrosequencing), and MGMT promoter methylation (methylation-specific polymerase chain reaction and bisulfite sequencing). Endpoints were overall survival, progression-free survival (PFS), time to malignant transformation, and postrecurrence survival. Radiotherapy was usually withheld until tumor progression/malignant transformation occurred. RESULTS: IDH1 mutations, TP53 mutations, and methylated MGMT promoters were seen in 78.1%, 51.2%, and 80.0% of the analyzed tumors, respectively. IDH1 mutations, which were significantly associated with TP53 mutations and/or MGMT promoter methylation (P < .001), resulted in shortened PFS (median, 47 vs 84 months; P = .004); postrecurrence survival, however, was significantly increased in those patients undergoing malignant transformation (median, 49 vs 13.5 months; P = .006). Overall survival was not affected by IDH1. A similar pattern of influence was seen for MGMT promoter methylation. Methylated tumors did significantly worse (better) in terms of PFS (postrecurrence survival); a low number of unmethylated tumors, however, limited the power of this analysis. Conversely, TP53 mutations were stringently associated with a worse prognosis throughout the course of the disease. CONCLUSIONS: IDH1 mutations are associated with a Janus headlike phenomenon; unfavorable prognostic influence on PFS turns into favorable impact on postrecurrence survival. A similar pattern of influence might exist for MGMT methylation.

Optical needle endoscope for safe and precise stereotactically guided biopsy sampling in neurosurgery.

Proper treatment of deep seated brain tumors requires correct histological diagnosis which unambiguously necessitates biopsy sampling. Stereotactically guided sampling of biopsies is widely used but bears the danger of incorrect sampling locations and damage to intracerebral blood vessels. Here, we present a minimally invasive contact endoscopic probe that can be inserted into the tissue inside a standard biopsy needle and allows for fluorescence detection of both tumorous tissue and intracerebral blood vessels. Outer diameter of our contact probe is smaller than 1.5 mm, field-of-view in the range of several hundred microns; the optical design allows for simultaneous detection and visualization of tissue autofluorescence and selective fluorescence signals from deep seated brain tumors and vasculature as shown on in vivo animal models. We demonstrate the tumor detection capability during stereotactic needle insertion in a clinical pilot trial. Using our probe, we expect stereotactic interventions to become safer and more precise and the technology might ultimately be used also for various other kinds of applications.

MRI-suspected low-grade glioma: is there a need to perform dynamic FET PET?

PURPOSE: Since differentiation between low-grade glioma (LGG) and high-grade glioma (HGG) remains challenging according to MRI criteria alone, we investigated the discriminative value of additional dynamic FET PET in patients with MRI-suspected LGG. METHODS: Included in this retrospective study were 127 patients with newly diagnosed MRI-suspected LGG and dynamic FET PET prior to histopathological assessment. FET PET lesions were visually classified as having reduced, normal, or increased tracer uptake. Maximal tumour uptake scaled to the mean background uptake (SUV(max)/BG), mean tumour uptake (SUV(mean)/BG), biological tumour volume and kinetics were evaluated and correlated with individual histopathological findings. RESULTS: Histopathological analysis revealed 71 patients with LGG, 47 patients with HGG (including 5 glioblastoma multiforme), 2 patients with low-grade ganglioglioma and 7 patients with non-neoplastic lesions. Of the 127 patients, 97 had lesions with increased FET uptake, of which 93 were neoplastic. Increased uptake was found in 49/71 LGG (69 %) and 42/47 HGG (89 %). None of the conventional uptake parameters differed significantly between the HGG and LGG groups. Kinetic analysis reliably identified HGG (sensitivity 95 %, specificity 72 %, PPV 74 %, NPV 95 %). Normal tracer uptake was observed in 19 patients (15 with LGG, 1 with HGG and 3 with non-neoplastic lesions) and reduced uptake in 11 patients (7 with LGG and 4 with HGG). CONCLUSION: Among the MRI-suspected LGG, kinetic but not conventional analysis of FET uptake enabled remarkably high sensitivity for detection of HGG. This held true even for lesions with low or diffuse tracer uptake. Lesions with reduced tracer uptake must be interpreted with caution, as they can also harbour HGG tissue.

Promoter methylation and expression of MGMT and the DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2 in paired primary and recurrent glioblastomas.

Epigenetic silencing of the O(6) -methylguanine-DNA methyltransferase (MGMT) gene promoter is associated with prolonged survival in glioblastoma patients treated with temozolomide (TMZ). We investigated whether glioblastoma recurrence is associated with changes in the promoter methylation status and the expression of MGMT and the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2 in pairs of primary and recurrent glioblastomas of 80 patients, including 64 patients treated with radiotherapy and TMZ after the first operation. Among the primary tumors, the MGMT promoter was methylated in 31 patients and unmethylated in 49 patients. In 71 patients (89%), the MGMT promoter methylation status of the primary tumor was retained at recurrence. MGMT promoter methylation, but not MGMT protein expression, was associated with longer progression-free survival, overall survival and postrecurrence survival (PRS). Moreover, PRS was increased under salvage chemotherapy. Investigation of primary and recurrent glioblastomas of 43 patients did not identify promoter methylation in any of the four MMR genes. However, recurrent glioblastomas demonstrated significantly lower MSH2, MSH6 and PMS2 protein expression as detected by immunohistochemistry. In conclusion, reduced expression of MMR proteins, but not changes in MGMT promoter methylation, is characteristic of glioblastomas recurring after the current standards of care.

Health-related quality of life and cognitive functioning in adult patients with supratentorial WHO grade II glioma: status prior to therapy.

The present prospective study intends to evaluate health-related quality of life (HRQL) and cognitive functioning in adult patients with supratentorial World Health Organization (WHO) grade II glioma (LGG) prior to observation/therapy and to determine possible influences of tumor-related factors on these measures. Adult patients with biopsy-proven supratentorial LGG were considered eligible (study period 18 months). Besides detailed documentation of patient clinical status we evaluated HRQL using the Short Form-36 (SF-36) Health Survey and applied the Beck Depression Inventory. Furthermore, attention and verbal memory functions were tested. Data from matched healthy control populations served as reference, and T-values were compared using Mann-Whitney U tests. For correlation of scores the Pearson test was utilized. Thirty-three patients with median Karnofsky Performance Status (KPS) of 80 were evaluated. Selective and divided attention showed significant impairment (P < 0.005), while verbal memory functions were unaffected. HRQL evaluated by SF-36 Health Survey was significantly reduced predominantly in the psychological domains (P < 0.025 to P < 0.0005). Nine patients displayed mild to moderate depression. Duration of symptoms >20 weeks and presence of seizures negatively affected aspects of HRQL, while cognitive functions were not influenced. KPS <80 correlated significant only with reduced physical functioning (P < 0.002) and role functioning (P < 0.01) on the SF-36 Health Survey. While displaying good clinical status, patients with LGG showed significant impairment in aspects of attention and affections of HRQL already at time of diagnosis. These results suggest that these impairments originate from the tumor and/or potentially from confrontation with the diagnosis itself.

Extended stereotactic brain biopsy in suspected primary central nervous system angiitis: good diagnostic accuracy and high safety.

OBJECTIVE: To evaluate the diagnostic accuracy and safety of extended stereotactic brain biopsy (ESBB) in a single center cohort with suspected primary angiitis of the central nervous system (PACNS). METHODS: A standardized stereotactic biopsy targeting MRI-positive lesions and collecting samples from the meninges and the cortex as well as from the white matter was performed in 23 patients with clinically suspected PACNS between 2010 and 2017. The relationship between biopsy yield and clinical characteristics, cerebrospinal fluid parameters, MR-imaging, time point of biopsy and exact localization of biopsy as well as number of tissue samples were examined. RESULTS: PACNS was confirmed in 7 of 23 patients (30.4%). Alternative diagnoses were identified in 7 patients (30%). A shorter time period between the onset or worsening of symptoms (p = 0.018) and ESBB significantly increased the diagnostic yield. We observed only minor and transient postoperative complications in 3 patients (13.0%). ESBB led to a direct change of the therapeutic regime in 13 of 23 patients (56.5%). Careful neuropathological analysis furthermore revealed that cortical samples were crucial in obtaining a diagnosis. CONCLUSION: ESBB is a safe approach with good feasibility, even in critically ill patients, and high diagnostic accuracy in patients with suspected PACNS changing future therapies in 13 of 23 patients (56.5%). Early biopsy after symptom onset/worsening is crucial and (sub)acute MRI-lesions should be targeted with a particular need for biopsy samples from the cortical layer.

Feasibility, safety, and outcome of frameless image-guided robotic radiosurgery for brain metastases.

We prospectively analyzed the safety and outcome of frameless image-guided robotic stereotactic radiosurgery (SRS) for treatment of brain metastases in patients that would have otherwise been treated with frame-based techniques. During a three-year period, 333 patients with 783 brain metastases of various histologies underwent 391 outpatient SRS procedures. Fifty-five percent of patients had multiple brain metastases. The median (mean) tumor volume was 1.0 cc (2.7 cc). The mean prescribed tumor dose was 18.5 Gy (+/-1.3 Gy). Local/distant tumor recurrences were treated by additional SRS for patients with stable systemic disease. Survival and freedom from local tumor recurrence was analyzed with the Kaplan-Meier method. Prognostic factors were obtained from the Cox proportional hazards model. System accuracy tests (end-to-end tests) were performed with a standard head phantom. Overall median survival was 12.2 months after SRS. The actuarial one-year local control rate was 95.2% (95% CI: 92.0-97.2); the distant brain tumor control rate was 67% (95% CI: 61.0-71.2). Most patients died from systemically progressing cancer (69%). A Karnofsky performance score (KPS) > 70 was related to prolonged survival in the univariate and multivariate analysis. Recursive partition analysis (RPA) classes I and II were related to prolonged survival in the univariate analysis. Twenty-one patients (6.3%) developed treatment-related neurotoxic effects; no patient died because of complications of SRS. Forty-five end-to-end tests documented a mean targeting accuracy of 0.48 +/- 0.22 mm. Single-session, frameless robotic SRS is feasible, accurate, and safe in selected patients with brain metastases of various primary tumors. There seems to be no difference in patient selection, adverse effects, treatment outcomes, or system accuracy compared with frame-based SRS.

Intramedullary low grade astrocytoma and ependymoma. Surgical results and predicting factors for clinical outcome.

INTRODUCTION: The optimal time point for surgery of intramedullary spinal astrocytomas and ependymomas is often debated on, as predicting factors are poorly defined. The current single-institutional study was conducted to retrospectively analyze prognostic factors for postoperative functional outcome in these patients. MATERIAL AND METHODS: All consecutive adult patients with intramedullary astrocytomas or ependymomas (except filum terminale ependymomas) were included. Imaging data, McCormick score (MCS), and detailed neurological evaluation were stringently applied preoperatively, 1 week, and 6 months postoperatively for functional evaluation of all patients. End points were early and late functional outcome. Prognostic factors were obtained from univariate and multivariate logistic regression analysis. RESULTS: Forty-four patients were included (29 ependymomas World Health Organization (WHO) grades I or II, 8 astrocytomas WHO grade I, and 7 astrocytomas WHO grade II). Overall perioperative morbidity was 34%, and there was no mortality. Complete tumor resection was achieved in 79% of ependymomas, 50% of astrocytomas WHO grade I, and 14% of astrocytomas WHO grade II (significantly more often in ependymomas than in astrocytomas, p < 0.05). Early and late functional outcome were highly intercorrelated (p < 0.01), but not correlated to histology. Preoperative MCS <3 and extent of tumor <5 levels were significantly (p = 0.01 and p < 0.05) associated with a favorable outcome (MCS <3) in early and late follow-up. CONCLUSION: An MCS of less than 3 and a tumor extent of less than 5 levels are the most important factors for a favorable postoperative functional outcome. Therefore, surgery should be initiated before significant clinical symptomatology or substantial tumor growth occurs.

The IL-1 Antagonist Anakinra Attenuates Glioblastoma Aggressiveness by Dampening Tumor-Associated Inflammation.

BACKGROUND: The recombinant IL-1 receptor antagonist anakinra-currently approved for the treatment of autoinflammatory diseases-blocks IL-1ß-mediated inflammatory signaling. As inflammation is a major driver of cancer, we hypothesized that anakinra might be able to mitigate glioblastoma (GBM) aggressiveness. METHODS: Primary GBM or T98G cells were incubated alone or with peripheral blood mononuclear cells (PBMCs) and were subsequently treated with IL-1ß and/or anakinra. T cells were obtained by magnetic bead isolation. Protein and mRNA expression were quantified by SDS-PAGE, qRT-PCR, and ELISA, respectively. Cell proliferation and apoptosis were analyzed via flow cytometry. Chemotaxis was studied via time-lapse microscopy. RESULTS: Upon IL-1ß stimulation, anakinra attenuated proinflammatory gene expression in both GBM cells and PBMCs, and mitigated tumor migration and proliferation. In a more lifelike model replacing IL-1ß stimulation by GBM-PBMC co-culture, sole presence of PBMCs proved sufficient to induce a proinflammatory phenotype in GBM cells with enhanced proliferation and migration rates and attenuated apoptosis. Anakinra antagonized these pro-tumorigenic effects and, moreover, reduced inflammatory signaling in T cells without compromising anti-tumor effector molecules. CONCLUSION: By dampening the inflammatory crosstalk between GBM and immune cells, anakinra mitigated GBM aggressiveness. Hence, counteracting IL-1ß-mediated inflammation might be a promising strategy to pursue.

MicroRNA-93 acts as an "anti-inflammatory tumor suppressor" in glioblastoma.

BACKGROUND: Inflammation is an important driver of malignant glioma disease. Inflammatory mediators are not only produced by immune cells in the tumor microenvironment, but also by glioblastoma (GBM) cells themselves creating a mutually reinforcing loop. We here aimed at identifying an "anti-inflammatory switch" that allows to dampen inflammation in GBM. METHODS: We used human GBM specimens, primary cultures, and cell lines. The response of GBM cells toward inflammatory stimuli was tested by incubation with supernatant of stimulated human immune cells. Expression levels were measured by whole transcriptome microarrays and qRT-PCR, and protein was quantified by LUMINEX and SDS-PAGE. MicroRNA binding to 3'UTRs was analyzed by luciferase assays. Proliferation rates were determined by flow cytometry, and invasion and angiogenesis were studied using migration and endothelial tube formation assays. RESULTS: We demonstrated GBM cells to secrete high amounts of proinflammatory mediators in an inflammatory microenvironment. We found miR-93 as a potential "anti-inflammatory tumor suppressor" dramatically downregulated in GBM. Concordantly, cytokine secretion dropped after miR-93 re-expression. Transfection of miR-93 in GBM cells led to down-regulation of hubs of the inflammatory networks, namely, HIF-1α and MAP3K2 as well as IL-6, G-CSF, IL-8, LIF, IL-1ß, COX2, and CXCL5. We showed only COX2 and CXCL5 to be indirectly regulated by miR-93 while all other genes are true targets. Phenotypically, re-expression of miR-93 in GBM cells substantially suppressed proliferation, migration, and angiogenesis. CONCLUSIONS: Alleviating GBM-derived inflammation by re-expression of miR-93 may be a powerful tool to mitigate these tumors' aggressiveness and holds promise for new clinical approaches.