Near-infrared spectroscopy to measure brain oxygenation: A comparison of measurements on the skin, skull and dura mater.

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.

Impact of hyperoxia and phenylephrine on cerebral oxygenation: An experimental clinical study.

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.

CNS infection in children with brain tumors: adding ventriculostomy to brain tumor resection increases risk more than 20-fold.

PURPOSE: To investigate the risk of central nervous system (CNS) infections in children undergoing neurosurgery for brain tumors. METHODS: Single-center retrospective cohort study including all children with brain tumors undergoing neurosurgical treatment over an 11-year period. RESULTS: A total of 274 patients undergoing 733 neurosurgical procedures were included. Overall, 12.8% of patients were diagnosed with a CNS infection during their course of treatment. CNS infections were more frequent among children treated with CSF diversion (p < 0.001) and independently associated with low age (OR/y 0.9 (CI 95% 0.769-0.941), intraventricular (OR 2.8, CI 95% 1.2-6.5), and high-grade tumors (OR 2.7, CI 95% 1.1-6.5). The majority of CNS infections occurred within 30 days of surgery, resulting in a postoperative CNS infection rate of 5.3%. Postoperative CNS infections were significantly more frequent following adjunct EVD placement during tumor resection compared to a stand-alone craniotomy (30.4% vs. 1.5%, RR 20.6, CI 95% 5.7-72.2). CONCLUSION: CNS infections affect at least 12% of children with brain tumors and are associated with age, tumor location, and grade. Adding EVD to tumor surgery increases the risk of postoperative CNS infection, and reconsidering routine adjunct EVD placement is therefore advocated.

Assessment of the Milan Complexity Scale for prediction of postoperative morbidity in pediatric neuro-oncological surgery.

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.

Implementation of TERT promoter mutations improve prognostication of the WHO classification in meningioma.

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.

Diagnostic yield of simultaneous dynamic contrast-enhanced magnetic resonance perfusion measurements and [18F]FET PET in patients with suspected recurrent anaplastic astrocytoma and glioblastoma.

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 lesions only [18F]FET positive and 97% in concordant positive lesions. CONCLUSION: The overall diagnostic accuracy of DCE BV imaging is good, but lower than that of [18F]FET PET. Adding DCE BV imaging did not improve the overall diagnostic accuracy of [18F]FET PET, but may improve specificity and allow better lesion-wise risk stratification than [18F]FET PET alone.

Somatostatin analogues in treatment-refractory meningioma: a systematic review with meta-analysis of individual patient data.

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.

A new uPAR-targeting fluorescent probe for optical guided intracranial surgery in resection of a meningioma-a case report.

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.

Proposal of a new grading system for meningioma resection: the Copenhagen Protocol.

INTRODUCTION: The extent of meningioma resection is the most fundamental risk factor for recurrence, and exact knowledge of extent of resection is necessary for prognostication and for planning of adjuvant treatment. Currently used classifications are the EANO-grading and the Simpson grading. The former comprises radiological imaging with contrast-enhanced MRI and differentiation between "gross total removal" and "subtotal removal," while the latter comprises a five-tiered differentiation of the surgeon's impression of the extent of resection. The extent of resection of tumors is usually defined via analyses of resection margins but has until now not been implemented for meningiomas. PET/MRI imaging with 68Ga-DOTATOC allows more sensitive and specific imaging than MRI following surgery of meningiomas. OBJECTIVE: To develop an objective grading system based on microscopic analyses of resection margins and sensitive radiological analyses to improve management of follow-up, adjuvant therapy, and prognostication of meningiomas. Based on the rationale of resection-margin analyses as gold standard and superior imaging performance of 68Ga DOTATOC PET, we propose "Copenhagen Grading" for meningiomas. RESULTS: Copenhagen Grading was described for six pilot patients with examples of positive and negative findings on histopathology and DOTATOC PET scanning. The grading could be traceably implemented and parameters of grading appeared complementary. Copenhagen Grading is prospectively implemented as a clinical standard at Rigshospitalet, Copenhagen. CONCLUSION: Copenhagen Grading provided a comprehensive, logical, and reproducible definition of the extent of resection. It offers promise to be the most sensitive and specific imaging modality available for meningiomas. Clinical and cost-efficacy remain to be established during prospective implementation.

Glioma surgery with intraoperative mapping-balancing the onco-functional choice.

BACKGROUND: Balancing survival versus risk of inducing functional deficits is a challenge when resecting gliomas in or near eloquent areas. Our objectives were to assess deficits prior to and at 6 and 12 months after awake craniotomies with cortical and subcortical mapping in patients with suspected grade 2 gliomas in eloquent areas. We analyzed whether pre- and intraoperative factors were linked to an increased risk of postoperative deficits. METHOD: Retrospective study of 92 consecutive patients operated between January 2010 and June 2014. All deficits reported by any healthcare professional and KPS-score preoperatively, immediately postoperatively (day 1-10), at 6 months and 12 months, were analyzed. RESULTS: A decrease in neurological and or cognitive function was common in the first days after surgery, with a significant improvement at 6 months after surgery and further improvement at 12 months. Immediately after surgery, 33% of the patients had severe deficits compared to 2% prior to surgery; this improved to 9% at 6 months and 3% at 12 months. However, at 12 months, 18% of the patients had new or worsened minor or moderate deficits and only 10% had no deficits compared to 39% prior to surgery. There were only minor changes in KPS. None of the recorded pre/intraoperative factors were found significantly to influence the risk of moderate/severe late postoperative deficits. CONCLUSION: A significant amount of the patients in this study experienced new or worsened neurological and or cognitive deficits during follow-up. We found a higher frequency of deficits than normally reported. This is due to the inclusion of mild deficits, the use of patient-reported data, and our focus on cognitive deficits. Our study indicates that the impact of awake craniotomy with mapping on patient outcome is larger than expected. This in no way negates the use of the technique.

Finding of IDH1 R132H mutation in histologically non-neoplastic glial tissue changes surgical strategies, a case report.

INTRODUCTION: In 2016, the WHO classification of diffuse astrocytoma began to include isocitrate dehydrogenase (IDH) mutation in addition to histology. RESULTS: We here demonstrate a case where a 14-year-old boy presented with a parietal tumor with no histological evidence of neoplasia but with an IDH1 mutation. Due to the IDH1 R132H mutation, the patient was diagnosed with diffuse astrocytoma WHO grade II and underwent successful gross total resection of this near-eloquently located tumor. CONCLUSION: This case exemplifies how inclusion of immunohistochemistry in tumor classification alters surgical strategy and might improve accuracy and time to diagnosis.

Effects of prostacyclin on cerebral blood flow and vasospasm after subarachnoid hemorrhage: randomized, pilot trial.

BACKGROUND AND PURPOSE: Delayed ischemic neurological deficits (DINDs) are a major contributing factor for poor outcome in patients with subarachnoid hemorrhage. In this trial, we investigated the therapeutic potential of prostacyclin, an endogen substance with known effect on vascular tone and blood flow regulation, on factors related to DIND. METHODS: This trial is a single-center, randomized, blinded, clinical, pilot trial with 3 arms. Ninety patients were randomized to continuous infusion of prostacyclin 1 ng/kg per minute, prostacyclin 2 ng/kg per minute, or placebo. The intervention was initiated day 5 after subarachnoid hemorrhage and discontinued day 10. Primary outcome was the difference in change from baseline in global cerebral blood flow. Secondary outcome measures were occurrence of DIND, angiographic vasospasm, and clinical outcome at 3 months. RESULTS: No statistically significant difference in change of global cerebral blood flow was found between the intervention groups. The observed incidence of DIND and angiographic vasospasm was markedly higher in the placebo group, although this difference was not statistically significant. No statistically significant differences in safety parameters or clinical outcome were found between the 3 groups. CONCLUSIONS: Administration of prostacyclin to patients with subarachnoid hemorrhage may be safe and feasible. Global cerebral blood flow after subarachnoid hemorrhage is not markedly affected by administration of prostacyclin in the tested dose range. It may be possible that the observed reduction in the point estimates of DIND and vasospasm in the prostacyclin groups represents an effect of prostacyclin as this trial was not powered to investigate the effect of prostacyclin on these outcomes. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01447095.

Primary intracranial angiomatoid fibrous histiocytoma presenting with anaemia and migraine-like headaches and aura as early clinical features.

A 17-year-old female with migraine with aura complained of fatigue and was diagnosed with anemia. Three years later, changes in her headache pattern prompted hospital referral. Brain MRI showed a bi-lobed extra-axial intracerebral tumor encroaching both parieto-occipital regions. The resection specimen yielded a rare diagnosis of primary intracranial angiomatoid fibrous histiocytoma (AFH). Tumor removal resulted in cessation of her migraine and anemia. AFH may cause systemic symptoms--in this case fatigue and anemia--long before focal neurological symptoms are present. This is the first report of an intracranial AFH presenting as migraine with visual aura and anemia.

The use of 5-ALA to assist complete removal of residual non-enhancing part of childhood medulloblastoma: a case report.

PURPOSE: Medulloblastoma is the most common malignant brain tumor in childhood. Radical surgery in the non-metastatic stage is an important factor with respect to overall survival. In this case, 5-aminolevulinic acid (5-ALA) was used at second-look surgery in order to improve surgical results. METHODS: The child was pretreated with 3 × 4 mg dexamethasone for 4 days prior to the second surgery. At 5 a.m. on the day of surgery, a freshly prepared solution of 5-ALA (20 mg/kg body weight; Medac, Germany) was given orally. RESULTS: At surgery, through the original opening, the vague red fluorescence of the tumor was clearly distinctive from the cerebellum with no tumor infiltration. All fluorescent tissue was removed. Postoperative MRI gave suspicion of yet at small tumor residue, but this structure is less than 1.5 ml in calculated volume, and consequently the recommended adjuvant therapy of the child changed from the high-risk medulloblastoma regimen to the standard-risk regimen. CONCLUSIONS: In this particular difficult case of non-contrast-enhancing tumor, 5-ALA was of vital importance to improve rate of resection and change the aggressiveness needed in postsurgery radiation therapy.

Real-time changes in brain tissue oxygen during endovascular treatment of cerebral vasospasm.

The use of endovascular intervention to treat cerebral vasospasm after subarachnoid hemorrhage has increased. Although the effect on angiographic vasospasm can be easily demonstrated, the effect on cerebral blood flow and clinical outcome is still controversial. In this report, we investigate minute-by-minute changes in brain tissue oxygen during balloon angioplasty and intraarterial administration of vasodilators in three patients.Our results confirm that endovascular intervention is capable of not only resolving angiographic vasospasm, but also of normalizing values of brain tissue oxygen pressure (PtiO2) in target parenchyma. However, during the intervention, dangerously low levels of brain tissue oxygen, leading to cerebral infarction, may occur. Thus, no clinical improvement was seen in two of the patients and a dramatic worsening was observed in the third patient. Because the decrease in brain tissue oxygen was seen after administration of vasopressor agents, this may be a contributing factor.

The use of Brainsuite iCT for frame-based stereotactic procedures.

BACKGROUND: Frame-based stereotactic procedures are the gold standard because of their superior stereotactic accuracy. The procedure used to be in multiple steps and was especially cumbersome and hazardous in intubated patients. A single-step procedure using intraoperative CT was created to optimize the procedures. METHODS: A combined fixation and low profile frame holder was designed for the operating table, allowing positioning for the scanning procedure immediately followed by the surgical biopsy procedure with the same positioning and head fixation. For placement of depth electrodes immediate CT control of positioning was feasible. RESULTS: In the first 8 months the procedure was successfully used 65 times including 8 times in pediatric cases. The procedure duration in awake patients was on average 81 min (range 33 to 202) and in intubated patients (children) on average 89 min (median 89, 78-100). DISCUSSION: This study demonstrates that frame-based stereotactic procedures in all brain locations are a feasible and practical technique with improved workflow and added patient safety and comfort.

Predicting the "usefulness" of 5-ALA-derived tumor fluorescence for fluorescence-guided resections in pediatric brain tumors: a European survey.

BACKGROUND: Five-aminolevulinic acid (Gliolan, medac, Wedel, Germany, 5-ALA) is approved for fluorescence-guided resections of adult malignant gliomas. Case reports indicate that 5-ALA can be used for children, yet no prospective study has been conducted as of yet. As a basis for a study, we conducted a survey among certified European Gliolan users to collect data on their experiences with children. METHODS: Information on patient characteristics, MRI characteristics of tumors, histology, fluorescence qualities, and outcomes were requested. Surgeons were further asked to indicate whether fluorescence was "useful", i.e., leading to changes in surgical strategy or identification of residual tumor. Recursive partitioning analysis (RPA) was used for defining cohorts with high or low likelihoods for useful fluorescence. RESULTS: Data on 78 patients <18 years of age were submitted by 20 centers. Fluorescence was found useful in 12 of 14 glioblastomas (85 %), four of five anaplastic astrocytomas (60 %), and eight of ten ependymomas grades II and III (80 %). Fluorescence was found inconsistently useful in PNETs (three of seven; 43 %), gangliogliomas (two of five; 40 %), medulloblastomas (two of eight, 25 %) and pilocytic astrocytomas (two of 13; 15 %). RPA of pre-operative factors showed tumors with supratentorial location, strong contrast enhancement and first operation to have a likelihood of useful fluorescence of 64.3 %, as opposed to infratentorial tumors with first surgery (23.1 %). CONCLUSIONS: Our survey demonstrates 5-ALA as being used in pediatric brain tumors. 5-ALA may be especially useful for contrast-enhancing supratentorial tumors. These data indicate controlled studies to be necessary and also provide a basis for planning such a study.

Thirty-day surgical morbidity and risk factors in pediatric brain tumor surgery: a 10-year nationwide retrospective study.

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 this large, population-based cohort, the authors show that postoperative morbidity is frequent, occurring in about two-thirds of all patients, largely driven by neurological deficits and CSF-related complications. In addition, infratentorial tumor location and younger age emerged as key risk factors for poor postoperative outcomes.

Prognostic relevance of radiological findings on early postoperative MRI for 187 consecutive glioblastoma patients receiving standard therapy.

Several prognostic factors are known to influence survival for patients treated with IDH-wildtype glioblastoma, but unknown factors may remain. We aimed to investigate the prognostic implications of early postoperative MRI findings. A total of 187 glioblastoma patients treated with standard therapy were consecutively included. Patients either underwent a biopsy or surgery followed by an early postoperative MRI. Progression-free survival (PFS) and overall survival (OS) were analysed for known prognostic factors and MRI-derived candidate factors: resection status as defined by the response assessment in neuro-oncology (RANO)-working group (no contrast-enhancing residual tumour, non-measurable contrast-enhancing residual tumour, or measurable contrast-enhancing residual tumour) with biopsy as reference, contrast enhancement patterns (no enhancement, thin linear, thick linear, diffuse, nodular), and the presence of distant tumours. In the multivariate analysis, patients with no contrast-enhancing residual tumour or non-measurable contrast-enhancing residual tumour on the early postoperative MRI displayed a significantly improved progression-free survival compared with patients receiving only a biopsy. Only patients with non-measurable contrast-enhancing residual tumour showed improved overall survival in the multivariate analysis. Contrast enhancement patterns were not associated with survival. The presence of distant tumours was significantly associated with both poor progression-free survival and overall survival and should be considered incorporated into prognostic models.

Immunotherapy drives mesenchymal tumour cell state shift and TME immune response in glioblastoma patients.

BACKGROUND: Glioblastoma is a highly aggressive type of brain tumour for which there is no curative treatment available. Immunotherapies have shown limited responses in unselected patients, and there is an urgent need to identify mechanisms of treatment resistance to design novel therapy strategies. METHODS: Here we investigated the phenotypic and transcriptional dynamics at single-cell resolution during nivolumab immune checkpoint treatment of glioblastoma patients. RESULTS: We present the integrative paired single-cell RNA-seq analysis of 76 tumour samples from patients in a clinical trial of the PD-1 inhibitor nivolumab and untreated patients. We identify a distinct aggressive phenotypic signature in both tumour cells and the tumour microenvironment in response to nivolumab. Moreover, nivolumab-treatment was associated with an increased transition to mesenchymal stem-like tumour cells, and an increase in TAMs and exhausted and proliferative T cells. We verify and extend our findings in large external glioblastoma dataset (n = 298), develop a latent immune signature and find 18% of primary glioblastoma samples to be latent immune, associated with mesenchymal tumour cell state and TME immune response. Finally, we show that latent immune glioblastoma patients are associated with shorter overall survival following immune checkpoint treatment (p = 0.0041). CONCLUSIONS: We find a resistance mechanism signature in a quarter of glioblastoma patients associated with a tumour-cell transition to a more aggressive mesenchymal-like state, increase in TAMs and proliferative and exhausted T cells in response to immunotherapy. These patients may instead benefit from neuro-oncology therapies targeting mesenchymal tumour cells.