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Background The reliability of near-infrared spectroscopy (NIRS) for measuring cerebral oxygenation (ScO2) is controversial due to the possible contamination from extracranial tissues. We compared ScO2 measured with the NIRS optode on the forehead, the skull and the dura mater in anaesthetised patients undergoing craniotomy. We hypothesised that ScO2 measured directly on the skull and the dura mater would differ from ScO2 measured on the skin. Methods This prospective observational study included 17 adult patients scheduled for elective craniotomy. After induction of general anaesthesia, ScO2 was measured on the forehead skin, as well as on the skull and on the dura mater in the surgical field. The primary comparison was the difference in ScO2 measured on the dura mater and on ScO2 measured on the skin; secondary comparisons were the differences in ScO2 on the skull and ScO2 on the skin and the dura mater, respectively. Data were described with median (5%–95% range) and analysed with the Wilcoxon signed-rank test. Results ScO2 values on the dura mater were obtained in 11 patients, and median ScO2 (48%, 29%–95%) did not differ significantly from ScO2 on the skin (73%, 49%–92%; p = .052), median difference −25% (−35.6% to −1.2%). ScO2 on the skull (N = 16) was lower than that on the skin (63% [43%–79%] vs. 75% [61%–94%]; p = .0002), median difference −10% (−20.8 to −3.0). Conclusion In adults undergoing craniotomy, NIRS-based ScO2 measured on the dura mater did not reach statistically significantly lower values than ScO2 measured on the skin, whereas values on the skull were lower than on the skin, indicating a contribution from scalp tissue to the signal., Background: The reliability of near-infrared spectroscopy (NIRS) for measuring cerebral oxygenation (ScO2) is controversial due to the possible contamination from extracranial tissues. We compared ScO2 measured with the NIRS optode on the forehead, the skull and the dura mater in anaesthetised patients undergoing craniotomy. We hypothesised that ScO2 measured directly on the skull and the dura mater would differ from ScO2 measured on the skin. Methods: This prospective observational study included 17 adult patients scheduled for elective craniotomy. After induction of general anaesthesia, ScO2 was measured on the forehead skin, as well as on the skull and on the dura mater in the surgical field. The primary comparison was the difference in ScO2 measured on the dura mater and on ScO2 measured on the skin; secondary comparisons were the differences in ScO2 on the skull and ScO2 on the skin and the dura mater, respectively. Data were described with median (5%–95% range) and analysed with the Wilcoxon signed-rank test. Results: ScO2 values on the dura mater were obtained in 11 patients, and median ScO2 (48%, 29%–95%) did not differ significantly from ScO2 on the skin (73%, 49%–92%; p =.052), median difference −25% (−35.6% to −1.2%). ScO2 on the skull (N = 16) was lower than that on the skin (63% [43%–79%] vs. 75% [61%–94%]; p =.0002), median difference −10% (−20.8 to −3.0). Conclusion: In adults undergoing craniotomy, NIRS-based ScO2 measured on the dura mater did not reach statistically significantly lower values than ScO2 measured on the skin, whereas values on the skull were lower than on the skin, indicating a contribution from scalp tissue to the signal.

Significance This third biennial intraoperative molecular imaging (IMI) conference shows how optical contrast agents have been applied to develop clinically significant endpoints that improve precision cancer surgery. Aim National and international experts on IMI presented ongoing clinical trials in cancer surgery and preclinical work. Previously known dyes (with broader applications), new dyes, novel nonfluorescence-based imaging techniques, pediatric dyes, and normal tissue dyes were discussed. Approach Principal investigators presenting at the Perelman School of Medicine Abramson Cancer Center’s third clinical trials update on IMI were selected to discuss their clinical trials and endpoints. Results Dyes that are FDA-approved or currently under clinical investigation in phase 1, 2, and 3 trials were discussed. Sections on how to move benchwork research to the bedside were also included. There was also a dedicated section for pediatric dyes and nonfluorescence-based dyes that have been newly developed. Conclusions IMI is a valuable adjunct in precision cancer surgery and has broad applications in multiple subspecialties. It has been reliably used to alter the surgical course of patients and in clinical decision making. There remain gaps in the utilization of IMI in certain subspecialties and potential for developing newer and improved dyes and imaging techniques., Significance: This third biennial intraoperative molecular imaging (IMI) conference shows how optical contrast agents have been applied to develop clinically significant endpoints that improve precision cancer surgery. Aim: National and international experts on IMI presented ongoing clinical trials in cancer surgery and preclinical work. Previously known dyes (with broader applications), new dyes, novel nonfluorescence-based imaging techniques, pediatric dyes, and normal tissue dyes were discussed. Approach: Principal investigators presenting at the Perelman School of Medicine Abramson Cancer Center's third clinical trials update on IMI were selected to discuss their clinical trials and endpoints. Results: Dyes that are FDA-approved or currently under clinical investigation in phase 1, 2, and 3 trials were discussed. Sections on how to move benchwork research to the bedside were also included. There was also a dedicated section for pediatric dyes and nonfluorescence-based dyes that have been newly developed. Conclusions: IMI is a valuable adjunct in precision cancer surgery and has broad applications in multiple subspecialties. It has been reliably used to alter the surgical course of patients and in clinical decision making. There remain gaps in the utilization of IMI in certain subspecialties and potential for developing newer and improved dyes and imaging techniques.

BACKGROUND: Despite considerable research effort, causes of brain cancer are largely unknown. Male brain cancer predominance and reduced brain cancer risk with increasing parity among women, however, support a favourable role of pregnancy. We set out to determine whether fetal-origin microchimerism, namely the presence and long-term persistence of fetal cells, likely obtained via natural trafficking across the placenta during pregnancy, associates with reduced risk of brain cancer in women.METHODS: Using a case-cohort design, we sampled 505 middle-aged women randomly at baseline in the Diet, Cancer and Health cohort (controls), and 73 women with incident brain cancer diagnosed during follow-up in the Danish Cancer Registry (cases). Male origin microchimerism was determined by presence of Y chromosome sequences in female blood samples. Data were analysed using weighted proportional Hazards regression, yielding Hazard Ratios with 95% confidence intervals.RESULTS: Compared with male origin microchimerism negative women, positive women had half the risk of developing brain cancer (Hazard Ratio = 0.50 [0.33-0.77]). Sensitivity analyses support that our findings are unlikely due to bias or chance.CONCLUSION: Here, for the first time, we demonstrate half the risk of brain cancer in male origin microchimerism positive compared with negative women. Our findings resemble those of previous studies of male origin microchimerism and other female cancers.

An early postoperative MRI is recommended following Glioblastoma surgery. This retrospective, observational study aimed to investigate the timing of an early postoperative MRI among 311 patients. The patterns of the contrast enhancement (thin linear, thick linear, nodular, and diffuse) and time from surgery to the early postoperative MRI were recorded. The primary endpoint was the frequencies of the different contrast enhancements within and beyond the 48-h from surgery. The time dependence of the resection status and the clinical parameters were analysed as well. The frequency of the thin linear contrast enhancements significantly increased from 99/183 (50.8%) within 48-h post-surgery to 56/81 (69.1%) beyond 48-h post-surgery. Similarly, MRI scans with no contrast enhancements significantly declined from 41/183 (22.4%) within 48-h post-surgery to 7/81 (8.6%) beyond 48-h post-surgery. No significant differences were found for the other types of contrast enhancements and the results were robust in relation to the choice of categorisation of the postoperative periods. Both the resection status and the clinical parameters were not statistically different in patients with an MRI performed before and after 48 h. The findings suggest that surgically induced contrast enhancements are less frequent when an early postoperative MRI is performed earlier than 48-h, supporting the recommendation of a 48-h window for an early postoperative MRI.

Background Oxygen supply to the brain is of special importance during intracranial surgery because it may be compromised by intracranial pathology. A high arterial blood pressure (mean arterial pressure above 80 mmHg) and a high arterial oxygen tension (PaO2 above 12 kPa) is therefore often targeted in these patients, when for example intracranial pressure is increased or when a mass effect on brain tissue from a tumour is present, and it is pursued by administering vasopressors such as phenylephrine and by increasing inspiratory oxygen fraction (FiO2). However, whether these interventions increase cerebral oxygenation remains uncertain. We aimed to investigate the effect of hyperoxia and phenylephrine on brain tissue oxygen tension (PbtO2) in patients undergoing craniotomy. Methods In this experimental study, we included 17 adult patients scheduled for elective craniotomy. After securing a stable baseline of the oxygen probe, PbtO2 was measured in white matter peripherally in the surgical field during general anaesthesia. Primary comparisons were PbtO2 before versus after an increase in FiO2 from 0.30 to 0.80 as well as before versus after a bolus dose of phenylephrine (0.1–0.2 mg depending on patient haemodynamics). Data were analysed with the Wilcoxon signed rank test. Results We obtained complete data sets in 11 patients undergoing the FiO2 increase and six patients receiving the phenylephrine bolus. PbtO2 was 22 (median; 5%–95% range, 4.6–54) mmHg during 30% oxygen, 68 (8.4–99) mmHg during 80% oxygen (p = .004 compared to 30% oxygen), 21 (4.5–81) mmHg before phenylephrine, and 19 (4.2–56) mmHg after phenylephrine (p = .56 compared to before phenylephrine). Conclusion In patients undergoing craniotomy under general anaesthesia, brain tissue oxygen tension increased with a high inspiratory oxygen fraction but remained unchanged after a bolus dose of phenylephrine.

OBJECTIVE Pediatric neuro-oncological surgery is often associated with significant risk; however, comprehensive data on surgical morbidity remain limited. The purpose of this study was therefore to provide national population-based data on both the incidence and characteristics of poor postoperative outcomes following pediatric intracranial neuro-oncological surgery. Additionally, the authors aimed to evaluate key risk factors for poor postoperative outcomes including overall morbidity, significant morbidity, and the most frequent types of morbidity. METHODS The authors conducted a registry-based, nationwide, retrospective study including all children receiving surgical treatment for a CNS tumor over a 10-year period. Patients were identified using the Danish Childhood Cancer Registry, and 30-day morbidity was assessed through manual review of electronic health records. Significant morbidity was defined as complications in need of treatment under general anesthesia, ICU admission, or persistent neurological deficits at 30 days following surgery or death. Risk factors including sex, age, tumor location, tumor malignancy grade, and preoperative hydrocephalus were investigated using multivariate logistic regression analysis. RESULTS A total of 349 children undergoing 473 tumor procedures were included, with an overall morbidity rate of 66.0% and a significant morbidity rate of 34.2%. The most frequent complications included neurological deficits (41.4%) and CSF-related morbidity consisting of CSF leaks, pseudomeningoceles, and postoperative hydrocephalus. Highly significant associations between infratentorial tumor location and both significant morbidity (OR 1.26, 95% CI 1.11–1.43; p < 0.001) and neurological deficits (OR 1.38, 95% CI 1.21–1.57; p < 0.001) were identified. In addition, younger age was revealed as a major risk factor of both postoperative CSF leakage and CSF-related morbidity in general. CONCLUSIONS In th, OBJECTIVE Pediatric neuro-oncological surgery is often associated with significant risk; however, comprehensive data on surgical morbidity remain limited. The purpose of this study was therefore to provide national population-based data on both the incidence and characteristics of poor postoperative outcomes following pediatric intracranial neuro-oncological surgery. Additionally, the authors aimed to evaluate key risk factors for poor postoperative outcomes including overall morbidity, significant morbidity, and the most frequent types of morbidity. METHODS The authors conducted a registry-based, nationwide, retrospective study including all children receiving surgical treatment for a CNS tumor over a 10-year period. Patients were identified using the Danish Childhood Cancer Registry, and 30-day morbidity was assessed through manual review of electronic health records. Significant morbidity was defined as complications in need of treatment under general anesthesia, ICU admission, or persistent neurological deficits at 30 days following surgery or death. Risk factors including sex, age, tumor location, tumor malignancy grade, and preoperative hydrocephalus were investigated using multivariate logistic regression analysis. RESULTS A total of 349 children undergoing 473 tumor procedures were included, with an overall morbidity rate of 66.0% and a significant morbidity rate of 34.2%. The most frequent complications included neurological deficits (41.4%) and CSF-related morbidity consisting of CSF leaks, pseudomeningoceles, and postoperative hydrocephalus. Highly significant associations between infratentorial tumor location and both significant morbidity (OR 1.26, 95% CI 1.11–1.43; p < 0.001) and neurological deficits (OR 1.38, 95% CI 1.21–1.57; p < 0.001) were identified. In addition, younger age was revealed as a major risk factor of both postoperative CSF leakage and CSF-related morbidity in general. CONCLUSIONS In th

MR-guided laser interstitial thermal therapy (LITT) is feasible and safe in the awake patient. Awake LITT may be performed with analgesics for head fixation in a head-ring, no sedation during laser ablation, and with continuous neurological testing in patients with brain tumors and epilepsy. In the LITT treatment of lesions near eloquent areas and subcortical fiber tracts, neurological function can potentially be preserved by monitoring the patient during laser ablation.

PURPOSE: To assess the performance of the risk-predicting Milan Complexity Scale (MCS) on postoperative morbidity in pediatric neuro-oncological surgery.METHODS: A retrospective dual-center review of children undergoing primary brain tumor resection in Denmark over a 10-year period. MCS scoring was performed based on preoperative imaging, blinded to individual outcomes. Surgical morbidity was registered according to existing complication scales and dichotomized as significant or nonsignificant morbidity. The MCS was evaluated using logistic regression modeling.RESULTS: 208 children (50% female, mean age 7.9 y, and SD 5.2) were included. Of the original "Big Five" predictors included in the MCS, only posterior fossa (OR: 2.31, 95% CI: 1.25-4.34, p-value = 0.008) and eloquent area (OR: 3.32, 95% CI: 1.50-7.68, p-value = 0.004) locations were significantly associated with increased risk of significant morbidity in our pediatric cohort. The absolute MCS score correctly classified 63.0% of cases. Its accuracy increased to 69.2% when mutually adjusting for each of the "Big Five" predictors with corresponding positive and negative predictive values of 66.2% and 71.0%, using a predicted probability cutoff of 0.5.CONCLUSION: The MCS is predictive of postoperative morbidity also in pediatric neuro-oncological surgery, although only two of its original five variables were significantly associated with poor outcome in children. The clinical value of the MCS is likely limited for the experienced pediatric neurosurgeon. Future clinically impactful risk-prediction tools should include a larger number of relevant variables and be tailored to the pediatric population.

BACKGROUND: The etiology of central nervous system (CNS) tumors in children is largely unknown and population-based studies of genetic predisposition are lacking.METHODS: In this prospective, population-based study, we performed germline whole-genome sequencing in 128 children with CNS tumors, supplemented by a systematic pedigree analysis covering 3,543 close relatives.RESULTS: Thirteen children (10%) harbored pathogenic variants in known cancer genes. These children were more likely to have medulloblastoma (OR 5.9, CI 1.6-21.2) and develop metasynchronous CNS tumors (p=0.01). Similar carrier frequencies were seen among children with low-grade glioma (12.8%) and high-grade tumors (12.2%). Next, considering the high mortality of childhood CNS tumors throughout most of human evolution, we explored known pediatric-onset cancer genes, showing that they are more evolutionarily constrained than genes associated with risk of adult-onset malignancies (p=5e-4) and all other genes (p=5e-17). Based on this observation, we expanded our analysis to 2 986 genes exhibiting high evolutionary constraint in 141 456 humans. This analysis identified eight directly causative loss-of-functions variants, and showed a dose-response association between degree of constraint and likelihood of pathogenicity - raising the question of the role of other highly constrained gene alterations detected.CONCLUSIONS: ∽10% of pediatric CNS tumors can be attributed to rare variants in known cancer genes. Genes associated with high risk of childhood cancer show evolutionary evidence of constraint.

OBJECTIVE WHO grade III meningiomas, also known as malignant meningiomas (MMs), are rare, and the heterogenous clinical course in patients with MM is not well described. To characterize the clinical course of patients with MM, granular clinical data were gathered from 51 patients treated at the Department of Neurosurgery and Radiation Oncology, Rigshospitalet, in Copenhagen, Denmark, between 2000 and 2020. METHODS The authors investigated outcome and timing in terms of 1) tumor progression and grade transformation in patients previously diagnosed with WHO grade I or II meningiomas (patients with a secondary MM [sMM]); 2) performance status and complications following surgery; and 3) transition to noncurative treatment and ultimately death. Complications, time between recurrences, and outcome (modified Rankin Scale [mRS] score) for every surgery were analyzed, both malignant and premalignant. RESULTS Of the 51 patients, 24 (47%) had an sMM. The time to WHO grade III transformation in the sMM group varied widely (median 5.5 years, range 0.5-22 years), but after transformation to a WHO grade III tumor, patients with an sMM and those with a primary MM (pMM) did not differ significantly in overall survival and cumulative risk of progression. Median overall survival for all 51 patients was 4.2 years (95% CI 2.6-7.2 years). Time from the decision to shift from curative to noncurative treatment until death was 3.8 months and the 30-day mortality rate following surgery was 11.8%. From a cumulative number of 151 surgeries, 10 surgeries were followed by improvement on the mRS, mRS score was unchanged in 70, and it worsened in 71. The MM was the underlying cause of death in 30 of 31 patients who had died at the end of follow-up. CONCLUSIONS Together, these findings clearly show a significant morbidity and mortality from the disease itself and from the treatment. These findings warrant studies of prognostic factors for earlier support and adjuvant measures in MM and identify

Purpose: Both amino acid positron emission tomography (PET) and magnetic resonance imaging (MRI) blood volume (BV) measurements are used in suspected recurrent high-grade gliomas. We compared the separate and combined diagnostic yield of simultaneously acquired dynamic contrast-enhanced (DCE) perfusion MRI and O-(2-[18F]-fluoroethyl)-L-tyrosine ([18F]FET) PET in patients with anaplastic astrocytoma and glioblastoma following standard therapy. Methods: A total of 76 lesions in 60 hybrid [18F]FET PET/MRI scans with DCE MRI from patients with suspected recurrence of anaplastic astrocytoma and glioblastoma were included retrospectively. BV was measured from DCE MRI employing a 2-compartment exchange model (2CXM). Diagnostic performances of maximal tumour-to-background [18F]FET uptake (TBRmax), maximal BV (BVmax) and normalised BVmax (nBVmax) were determined by ROC analysis using 6-month histopathological (n = 28) or clinical/radiographical follow-up (n = 48) as reference. Sensitivity and specificity at optimal cut-offs were determined separately for enhancing and non-enhancing lesions. Results: In progressive lesions, all BV and [18F]FET metrics were higher than in non-progressive lesions. ROC analyses showed higher overall ROC AUCs for TBRmax than both BVmax and nBVmax in both lesion-wise (all lesions, p = 0.04) and in patient-wise analysis (p < 0.01). Combining TBRmax with BV metrics did not increase ROC AUC. Lesion-wise positive fraction/sensitivity/specificity at optimal cut-offs were 55%/91%/84% for TBRmax, 45%/77%/84% for BVmax and 59%/84%/72% for nBVmax. Combining TBRmax and best-performing BV cut-offs yielded lesion-wise sensitivity/specificity of 75/97%. The fraction of progressive lesions was 11% in concordant negative lesions, 33% in lesions only BV positive, 64% in les

Germline pathogenic variants in CDKN2A predispose to various cancers, including melanoma, pancreatic cancer, and neural system tumors, whereas CDKN2B variants are associated with renal cell carcinoma. A few case reports have described heterozygous germline deletions spanning both CDKN2A and CDKN2B associated with a cancer predisposition syndrome (CPS) that constitutes a risk of cancer beyond those associated with haploinsufficiency of each gene individually, indicating an additive effect or a contiguous gene deletion syndrome. We report a young woman with a de novo germline 9p21 microdeletion involving the CDKN2A/CDKN2B genes, who developed six primary cancers since childhood, including a very rare extraskeletal osteosarcoma (eOS) at the age of 8. To our knowledge this is the first report of eOS in a patient with CDKN2A/CDKN2B deletion.

Ependymoma is the second most common malignant brain tumor in children. The etiology is largely unknown and germline DNA sequencing studies focusing on childhood ependymoma are limited. We therefore performed germline whole-genome sequencing on a population-based cohort of children diagnosed with ependymoma in Denmark over the past 20 years (n = 43). Single nucleotide and structural germline variants in 457 cancer related genes and 2986 highly evolutionarily constrained genes were assessed in 37 children with normal tissue available for sequencing. Molecular ependymoma classification was performed using DNA methylation profiling for 39 children with available tumor tissue. Pathogenic germline variants in known cancer predisposition genes were detected in 11% (4/37; NF2, LZTR1, NF1 & TP53). However, DNA methylation profiling resulted in revision of the histopathological ependymoma diagnosis to non-ependymoma tumor types in 8% (3/39). This included the two children with pathogenic germline variants in TP53 and NF1 whose tumors were reclassified to a diffuse midline glioma and a rosette-forming glioneuronal tumor, respectively. Consequently, 50% (2/4) of children with pathogenic germline variants in fact had other tumor types. A meta-analysis combining our findings with pediatric pan-cancer germline sequencing studies showed an overall frequency of pathogenic germline variants of 3.4% (7/207) in children with ependymoma. In summary, less than 4% of childhood ependymoma is explained by genetic predisposition, virtually restricted to pathogenic variants in NF2 and NF1. For children with other cancer predisposition syndromes, diagnostic reconsideration is recommended for ependymomas without molecular classification. Additionally, LZTR1 is suggested as a novel putative ependymoma predisposition gene.

Hyperlactatemia occurs frequently after brain tumor surgery. Existing studies are scarce and predominantly retrospective, reporting inconsistent associations to new neurological deficits and prolonged hospital stay. Here we describe a protocol for a prospective observational study of hyperlactatemia during and after elective tumor craniotomy and the association with postoperative outcome, as well as selected pathophysiological aspects, and possible risk factors. We will include 450 brain tumor patients scheduled for elective craniotomy. Arterial blood samples for lactate and glucose measurement will be withdrawn hourly during surgery and until six hours postoperatively. To further explore the association of hyperlactatemia with perioperative insulin resistance, additional blood sampling measuring markers of insulin resistance will be done in 100 patients. Furthermore, in a subgroup of 20 patients, blood from a jugular bulb catheter will be drawn simultaneously with blood from the radial artery to measure the arterial to jugular venous concentration difference of lactate, in order to study the direction of cerebrovascular lactate flux. Functional clinical outcome will be determined by the modified Rankin Scale, length of stay and mortality at 30 days, 6 months, 1 year and 5 years. Clinical outcome will be compared between patients with and without hyperlactatemia. Multivariate logistic regression will be used to identify risk factors for hyperlactatemia. A statistical analysis plan will be publicized to support transparency and reproducibility. Results will be published in a peer-reviewed journal and presented at international conferences.

Treatment-refractory meningiomas have a dismal prognosis and limited treatment options. Meningiomas express high-densities of somatostatin receptors (SSTR), thus potentially susceptible to antitumorigenic effects of somatostatin analogues (SSA). Evidence for SSA in meningiomas is scarce, and it is unclear if published literature would either (1) support wider use of SSA, if (2) more evidence is desirable, or if (3) available evidence is sufficient to discard SSA. We addressed the need for more evidence with a systematic review and meta-analysis. We performed an individual patient data (IPD) meta-analysis. Main outcomes were toxicity, best radiological response, progression-free survival, and overall survival. We applied multivariable logistic regression models to estimate the effect of SSA on the probability of obtaining radiological disease control. The predictive performance was evaluated using area under the curve and Brier scores. We included 16 studies and compiled IPD from 8/9 of all previous cohorts. Quality of evidence was overall ranked “very low.” Stable disease was reported in 58% of patients as best radiological response. Per 100 mg increase in total SSA dosage, the odds ratios for obtaining radiological disease control was 1.42 (1.11 to 1.81, P = 0.005) and 1.44 (1.00 to 2.08, P = 0.05) for patients treated with SSA as monodrug therapy vs SSA in combination with everolimus, respectively. Low quality of evidence impeded exact quantification of treatment efficacy, and the association between response and treatment may represent reverse causality. Yet, the SSA treatment was well tolerated, and beneficial effect cannot be disqualified. A prospective trial without bias from inconsistent study designs is warranted to assess SSA therapy for well-defined meningioma subgroups.

Meningiomas are benign lesion although anot insignificant number experiences recurrences despite Simpson grade 1 removal. FG001 is a compound with a fluorophore (ICG) that binds to a urokinase-type plasminogen activator receptor (uPAR) and is currently investigated at our institution in a first-in-human trial. The patient presented with a plausible malignant glioma but proved to be a grade 1 meningioma. FG001 could delineated the tumor not only on the surface but supplementary in the cavity to remove safely the dural attachment. We present FG001 as a new promising tool for improved surgical radicality beyond the intended indication, provided that a prospective validation in a consecutive meningioma cohort demonstrates similar results.

TERT promoter mutations have been associated with increased risk of recurrence in meningioma cohorts, thus a potential biomarker for aggressive phenotypes. A main purpose of refining tumour classification is better predictions on the patient level. We compiled data from previous published cohorts to investigate patient-level predictions of recurrence based on TERTp-mut status. Implementation of TERTp-mut into the WHO grading led to better patient prognostication by improved prediction of recurrence. Our results support implementation of TERTp-mut into diagnostics and classification of meningiomas

Treatment of glioblastoma (GBM) remains a challenging task, with limited treatment options, none offering a cure. Immune therapy has proven effective across different cancers with remarkable response rates. Tumor mutational burden (TMB) is a marker of response, but technical and methodological differences in TMB estimates have made a proper assessment and comparison challenging. Here, we analyzed a prospective collection of paired samples from 35 patients with newly diagnosed GBM, all of whom were wild-type (WT) for isocitrate dehydrogenase, before and after treatment with radiotherapy and temozolomide. Seven patients (20%) had O6-methylguanine-DNA methyltransferase-methylated tumors. Six patients (17%) had two relapse surgeries, and tissue from all three surgeries was collected. We found that accurate evaluation of TMB was confounded by high variability in the cancer cell fraction of relapse samples. To ameliorate this, we developed a model to adjust for tumor purity based on the relative density distribution of variant allele frequencies in each primary–relapse pair. Additionally, we examined the mutation spectra of shared and private mutations. After tumor purity adjustment, we found TMB comparison reliable in tumors with tumor purity between 15% and 40%, resulting in 27/35 patients (77.1%). TMB remained unchanged from 0.65 mutations per megabase (Mb) to 0.67/Mb before and after treatment, respectively. Examination of the mutation spectra revealed a dominance of C > T transitions at CpG sites in both shared and relapse-private mutations, consistent with cytosine deamination and the clock-like mutational signature 1. We present and apply a cellularity correction approach that enables more accurate assessment of TMB in paired tumor samples. We did not find a significant increase in TMB after correcting for cancer cell fraction. Our study raises significant concerns when determining TMB. Although a small sample size, corrected TMB can have a clinical significa

Glioblastomas (GBM) are heterogeneous highly vascular brain tumors exploiting the unique microenvironment in the brain to resist treatment and anti-tumor responses. Anti-angiogenic agents, immunotherapy, and targeted therapy have been studied extensively in GBM patients over a number of decades with minimal success. Despite maximal efforts, prognosis remains dismal with an overall survival of approximately 15 months. Bevacizumab, a humanized anti-vascular endothelial growth factor (VEGF) antibody, underwent accelerated approval by the U.S. Food and Drug Administration in 2009 for the treatment of recurrent GBM based on promising preclinical and early clinical studies. Unfortunately, subsequent clinical trials did not find overall survival benefit. Pursuing pleiotropic targets and leaning toward multitarget strategies may be a key to more effective therapeutic intervention in GBM, but preclinical evaluation requires careful consideration of model choices. In this study, we discuss bevacizumab resistance, dual targeting of pro-angiogenic modulators VEGF and YKL-40 in the context of brain tumor microenvironment, and how model choice impacts study conclusions and its translational significance.

MR-guided laser interstitial thermal therapy (LITT) is a minimally invasive neurosurgical procedure, which in the last decade has gained significant momentum of the treatment of intracranial tumours and epileptic foci. In brief, LITT utilises the heat from a stereotactically placed laser catheter to selectively ablate a lesion or a structure under real-time MRI guidance, which is summarised and discussed in this review. The first LITT system gained FDA approval in 2007 and was CE-marked in 2018. In December 2020, the first patient with recurrent glioblastoma was treated at the Department of Neurosurgery at Rigshospitalet, Copenhagen.

For the radiological assessment of resection of high-grade gliomas, a 72-h diagnostic window is recommended to limit surgically induced contrast enhancements. However, such enhancements may occur earlier than 72 h post-surgery. This systematic review aimed to assess the evidence on the timing of the postsurgical MRI. PubMed, Embase, Web of Science and Cochrane were searched following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only original research articles describing surgically induced contrast enhancements on MRI after resection for high-grade gliomas were included and analysed. The frequency of different contrast enhancement patterns on intraoperative MRI (iMRI) and early postoperative MRI (epMRI) was recorded. The search resulted in 1443 studies after removing duplicates, and a total of 12 studies were chosen for final review. Surgically induced contrast enhancements were reported at all time points after surgery, including on iMRI, but their type and frequency vary. Thin linear contrast enhancements were commonly found to be surgically induced and were less frequently recorded on postoperative days 1 and 2. This suggests that the optimal time to scan may be at or before this time. However, the evidence is limited, and higher-quality studies using larger and consecutively sampled populations are needed.

BACKGROUND: Central nervous system (CNS) tumors cause the highest death rates among childhood cancers, and survivors frequently have severe late effects. Magnetic resonance imaging (MRI) is the imaging modality of choice, but its specificity can be challenged by treatment-induced signal changes. In adults, O-(2-[ 18F]fluoroethyl)-L-tyrosine ([ 18F]FET) PET can assist in interpreting MRI findings. We assessed the clinical impact and diagnostic accuracy of adding [ 18F]FET PET to MRI in children with CNS tumors.METHODS: A total of 169 [ 18F]FET PET scans were performed in 97 prospectively and consecutively included patients with known or suspected childhood CNS tumors. Scans were performed at primary diagnosis, before or after treatment, or at relapse.RESULTS: Adding [ 18F]FET PET to MRI impacted clinical management in 8% [95% confidence interval (CI): 4-13%] of all scans (n=151) and in 33% [CI: 17-53%] of scans deemed clinically indicated due to difficult decision-making on MRI alone (n=30). Using pathology or follow-up as reference standard, the addition of [ 18F]FET PET increased specificity (1.00 [0.82-1.00] vs. 0.48 [0.30-0.70], p=0.0001) and accuracy (0.91 [CI: 0.87-0.96] vs. 0.81 [CI: 0.75-0.89], p=0.04) in 83 treated lesions and accuracy in 58 untreated lesions (0.96 [CI:0.91-1.00] vs 0.90 [CI:0.82-0.92], p<0.001). Further, in a subset of patients (n=15) [ 18F]FET uptake correlated positively with genomic proliferation index.CONCLUSIONS: The addition of [ 18F]FET PET to MRI helped discriminate tumor from non-tumor lesions in the largest consecutive cohort of pediatric CNS tumor patients presented to date.