Development and Performance Evaluation of a Clinical Predictive Model to Estimate the Risk of Red Blood Cell Requirements in Brain Tumor Surgery.

BACKGROUND: The identification of factors associated with perioperative red blood cell (RBC) transfusion provides an opportunity to optimize the patient and surgical plan, and to guide perioperative crossmatch and RBC orders. We examined the association among potential bleeding risk factors and RBC requirements to develop a novel predictive model for RBC transfusion in patients undergoing brain tumor surgery. METHODS: This retrospective study included 696 adults who underwent brain tumor surgery between 2008 and 2018. Multivariable logistic regression with backward stepwise selection for predictor selection was used during modeling. Model performance was evaluated using area under the receiver operating characteristic curve, and calibration was evaluated with Hosmer-Lemeshow goodness-of-fit χ 2 -estimate. RESULTS: Preoperative hemoglobin level was inversely associated with the probability of RBC transfusion (odds ratio [OR]: 0.50; 95% confidence interval [CI]: 0.39-0.63; P <0.001). The need for RBC transfusion was also greater in patients who had a previous craniotomy (OR: 2.71; 95% CI: 1.32-5.57; P =0.007) and in those with larger brain tumor volume (OR: 1.01; 95% CI: 1.00-1.02; P =0.009). The relationship between number of planned craniotomy sites and RBC transfusion was not statistically significant (OR: 2.11; 95% CI: 0.61-7.32; P =0.238). A predictive model for RBC requirements was built using these 4 variables. The area under the receiver operating characteristic curve was 0.79 (95% CI: 0.70-0.87; P <0.001) showing acceptable calibration for predicting RBC transfusion requirements. CONCLUSIONS: RBC requirements in patients undergoing brain tumor surgery can be estimated with acceptable accuracy using a predictive model based on readily available preoperative clinical variables. This predictive model could help to optimize both individual patients and surgical plans, and to guide perioperative crossmatch orders.

Low grade gliomas guide-lines elaborated by the tumor section of Spanish Society of Neurosurgery.

Adult low-grade gliomas (Low Grade Gliomas, LGG) are tumors that originate from the glial cells of the brain and whose management involves great controversy, starting from the diagnosis, to the treatment and subsequent follow-up. For this reason, the Tumor Group of the Spanish Society of Neurosurgery (GT-SENEC) has held a consensus meeting, in which the most relevant neurosurgical issues have been discussed, reaching recommendations based on the best scientific evidence. In order to obtain the maximum benefit from these treatments, an individualised assessment of each patient should be made by a multidisciplinary team. Experts in each LGG treatment field have briefly described it based in their experience and the reviewed of the literature. Each area has been summarized and focused on the best published evidence. LGG have been surrounded by treatment controversy, although during the last years more accurate data has been published in order to reach treatment consensus. Neurosurgeons must know treatment options, indications and risks to participate actively in the decision making and to offer the best surgical treatment in every case.

Brain metastasis treatment guidelines: consensus by the Spanish Society of Neurosurgery Tumor Section.

Brain metastases are tumors that arise from a tumor cell originated in another organ reaching the brain through the blood. In the brain this tumor cell is capable of growing and invading neighboring tissues, such as the meninges and bone. In most patients a known tumor is present when the brain lesion is diagnosed, although it is possible that the first diagnose is the brain tumor before there is evidence of cancer elsewhere in the body. For this reason, the neurosurgeon must know the management that has shown the greatest benefit for brain metastasis patients, so treatments can be streamlined and optimized. Specifically, in this document, the following topics will be developed: selection of the cancer patient candidate for surgical resection and the role of the neurosurgeon in the multidisciplinary team, the importance of immunohistological and molecular diagnosis, surgical techniques, radiotherapy techniques, treatment updates of chemotherapy and immunotherapy and management algorithms in brain metastases. With this consensus manuscript, the tumor group of the Spanish Society of Neurosurgery (GT-SENEC) exposes the most relevant neurosurgical issues and the fundamental aspects to harmonize multidisciplinary treatment, especially with the medical specialties that are treating or will treat these patients.

Prognostic value of ventricular wall fluorescence during 5-aminolevulinic-guided surgery for glioblastoma.

BACKGROUND: The meaning of the ventricular wall fluorescence during 5-aminolevulinic (5-ALA)-guided surgery in patients with glioblastoma (GBM) is still unknown. The authors studied the association between ventricle fluorescence, clinical outcome and survival, and described the histopathological findings of selective biopsies from the ventricular wall. METHODS: One hundred and forty patients diagnosed of GBM underwent fluorescence-guided surgery (FGS); 65 of them were naive GBM and ventricle fluorescence during surgery was annotated prospectively. Selective biopsies were collected from the ventricular wall when possible. Clinical and radiological data were registered, including age, Karnofsky Performance Scale (KPS) score, presence of hydrocephalus, overall survival (OS), tumour volume and location (periventricular vs non-periventricular) and leptomeningeal dissemination. RESULTS: During FGS the ventricle wall was opened just when the tumour was periventricular in the preoperative MRI (45 out of 65). In 28 of them (60 %) the fluorescence extended far away from the site of opening, while in 17 it ended just in the few millimetres around the tumour. All four patients who developed hydrocephalus had periventricular tumours and the ventricle wall had been opened during surgery. Statistically significant differences were seen in OS according to periventricular location (15 m vs 33 m, P = 0.008 log rank). However, there was not significant relationship between ventricle fluorescence and hydrocephalus (P = 0.75), nor survival (14 m vs 15.5 m, P = 0.64). CONCLUSIONS: Preoperative MRI predicts if the ventricle will be opened using the 5-ALA fluorescence, according to tumour location. It does not predict, however if the ventricle wall is going to be fluorescent or not. The fluorescence of the ventricle wall is not a predictor for complications or survival. Periventricular tumour location is an independent bad prognostic factor in GBM.

Surgery guided by 5-aminolevulinic fluorescence in glioblastoma: volumetric analysis of extent of resection in single-center experience.

We analyzed the efficacy and applicability of surgery guided by 5-aminolevulinic acid (ALA) fluorescence in consecutive patients with glioblastoma multiforme (GBM). Thirty-six patients with GBM were operated on using ALA fluorescence. Resections were performed using the fluorescent light to assess the right plane of dissection. In each case, biopsies with different fluorescent quality were taken from the tumor center, from the edges, and from the surrounding tissue. These samples were analyzed separately with hematoxylin-eosin examination and immunostaining against Ki67. Tumor volume was quantified with pre- and postoperative volumetric magnetic resonance imaging. Strong fluorescence identified solid tumor with 100% positive predictive value. Invaded tissue beyond the solid tumor mass was identified by vague fluorescence with 97% positive predictive value and 66% negative predictive value, measured against hematoxylin-eosin examination. All the contrast-enhancing volume was resected in 83.3% of the patients, all patients had resection over 98% of the volume and mean volume resected was 99.8%. One month after surgery there was no mortality, and new or increased neurological morbidity was 8.2%. The fluorescence induced by 5-aminolevulinic can help to achieve near total resection of enhancing tumor volume in most surgical cases of GBM. It is possible during surgery to obtain separate samples of the infiltrating cells from the tumor border.

Erratum: miR-425-5p, a SOX2 target, regulates the expression of FOXJ3 and RAB31 and promotes the survival of GSCs.

[This corrects the article PMC7470213.].

Intraoperative imaging in the neurosurgery operating theatre: A review of the most commonly used techniques for brain tumour surgery. / Imagen intraoperatoria en el quirófano de neurocirugía: revisión de las técnicas más empleadas para la cirugía de los tumores cerebrales.

INTRODUCTION: New intraoperative imaging techniques, which aim to improve tumour resection, have been implemented in recent years in brain tumour surgery, although they lead to an increase in resources. In order to carry out an update on this topic, this manuscript has been drafted by a group from the Sociedad Española de Neurocirugía (Spanish Society of Neurosurgery). MATERIAL AND METHODS: Experts in the use of each one of the most-used intraoperative techniques in brain tumour surgery were presented with a description of the technique and a brief review of the literature. Indications for use, their advantages and disadvantages based on clinical experience and on what is published in the literature will be described. RESULTS: The most robust intraoperative imaging technique appears to be low- and high-field magnetic resonance imaging, but this is the technique which results in the greatest expenditure. Intraoperative ultrasound navigation is portable and less expensive, but it provides poorer differentiation of high-grade tumours and is observer-dependent. The most-used fluorescence techniques are 5-aminolevulinic acid for high-grade gliomas and fluorescein, useful in lesions which rupture the blood-brain barrier. Last of all, intraoperative CT is more versatile in the neurosurgery operating theatre, but it has fewer indications in neuro-oncology surgery. CONCLUSIONS: Intraoperative imaging techniques are used with increasingly greater frequency in brain tumour surgery, and the neurosurgeon should assess their possible use depending on their resources and the needs of each patient.

Glioblastoma treatment guidelines: Consensus by the Spanish Society of Neurosurgery Tumor Section. / Consenso sobre guías de tratamiento de los glioblastomas elaborado por el Grupo de Trabajo de Neurooncología (GTNO) de la SENEC.

INTRODUCTION: Glioblastoma (GBM) treatment starts in most patients with surgery, either resection surgery or biopsy, to reach a histology diagnose. Multidisciplinar team, including specialists in brain tumors diagnose and treatment, must make an individualize assessment to get the maximum benefit of the available treatments. MATERIAL AND METHODS: Experts in each GBM treatment field have briefly described it based in their experience and the reviewed of the literature. RESULTS: Each area has been summarized and the consensus of the brain tumor group has been included at the end. CONCLUSIONS: GBM are aggressive tumors with a dismal prognosis, however accurate treatments can improve overall survival and quality of life. Neurosurgeons must know treatment options, indications and risks to participate actively in the decision making and to offer the best surgical treatment in every case.

miR-425-5p, a SOX2 target, regulates the expression of FOXJ3 and RAB31 and promotes the survival of GSCs.

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults and prognosis is poor despite maximum therapeutic efforts. GBM is composed of heterogeneous cell populations, among which the glioma stem-like cells (GSCs) play an important role in tumor cell self-renewal and the ability to initiate and drive tumor growth and recurrence. The transcription factor SOX2 is enriched in GSCs where it controls the stem cell phenotype, invasion and maintenance of tumorigenicity. Therefore, understanding the molecular mechanisms governed by SOX2 in GSCs is crucial to developing targeted therapies against this resistant cell population. In this study, we identified and validated a miRNA profile regulated by SOX2 in GSCs. Among these miRNAs, miR-425-5p emerged as a significant robust candidate for further study. The expression of miR-425-5p was significantly enriched in clinical GBM specimens compared with a human brain reference sample and showed a positive correlation with SOX2 expression. Using a combination of in silico analyses and molecular approaches, we show that SOX2 binds to the promoter of miR-425-5p. Loss of function studies show that repressing miR-425-5p expression in multiple GSCs inhibited neurosphere renewal and induced cell death. More importantly, miR-425-5p inhibition extended survival in an orthotopic GBM mouse model. Finally, combining several bioinformatics platforms with biological endpoints in multiple GSC lines, we identified FOXJ3 and RAB31 as high confidence miR-425-5p target genes. Our findings show that miR-425-5p is a GBM stem cell survival factor and that miR-425-5p inhibition function is a potential strategy for treating GBM.

RNU6-1 in circulating exosomes differentiates GBM from non-neoplastic brain lesions and PCNSL but not from brain metastases.

BACKGROUND: Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. Circulating biomarkers may assist in the processes of differential diagnosis and response assessment. GBM cells release extracellular vesicles containing a subset of proteins and nucleic acids. We previously demonstrated that exosomes isolated from the serum of GBM patients had an increased expression of RNU6-1 compared to healthy subjects. In this exploratory study, we investigated the role of this small noncoding RNA as a diagnostic biomarker for GBM versus other brain lesions with some potential radiological similarities. METHODS: We analyzed the expression of RNU6-1 in circulating exosomes of GBM patients (n = 18), healthy controls (n = 30), and patients with subacute stroke (n = 30), acute/subacute hemorrhage (n = 30), acute demyelinating lesions (n = 18), brain metastases (n = 21), and primary central nervous system lymphoma (PCNSL; n = 12) using digital droplet PCR. RESULTS: Expression of RNU6-1 was significantly higher in GBM patients than in healthy controls (P = .002). RNU6-1 levels were also significantly higher in exosomes from GBM patients than from patients with non-neoplastic lesions (stroke [P = .05], hemorrhage [P = .01], demyelinating lesions [P = .019]) and PCNSL (P = .004). In contrast, no significant differences were found between patients with GBM and brain metastases (P = .573). Receiver operator characteristic curve analyses supported the role of this biomarker in differentiating GBM from subacute stroke, acute/subacute hemorrhage, acute demyelinating lesions, and PCNSL (P < .05), but again not from brain metastases (P = .575). CONCLUSIONS: Our data suggest that the expression of RNU6-1 in circulating exosomes could be useful for the differentiation of GBM from non-neoplastic brain lesions and PCNSL, but not from brain metastases.

The oncolytic virus Delta-24-RGD elicits an antitumor effect in pediatric glioma and DIPG mouse models.

Pediatric high-grade glioma (pHGG) and diffuse intrinsic pontine gliomas (DIPGs) are aggressive pediatric brain tumors in desperate need of a curative treatment. Oncolytic virotherapy is emerging as a solid therapeutic approach. Delta-24-RGD is a replication competent adenovirus engineered to replicate in tumor cells with an aberrant RB pathway. This virus has proven to be safe and effective in adult gliomas. Here we report that the administration of Delta-24-RGD is safe in mice and results in a significant increase in survival in immunodeficient and immunocompetent models of pHGG and DIPGs. Our results show that the Delta-24-RGD antiglioma effect is mediated by the oncolytic effect and the immune response elicited against the tumor. Altogether, our data highlight the potential of this virus as treatment for patients with these tumors. Of clinical significance, these data have led to the start of a phase I/II clinical trial at our institution for newly diagnosed DIPG (NCT03178032).

Oncolytic Viruses as Therapeutic Tools for Pediatric Brain Tumors.

In recent years, we have seen an important progress in our comprehension of the molecular basis of pediatric brain tumors (PBTs). However, they still represent the main cause of death by disease in children. Due to the poor prognosis of some types of PBTs and the long-term adverse effects associated with the traditional treatments, oncolytic viruses (OVs) have emerged as an interesting therapeutic option since they displayed safety and high tolerability in pre-clinical and clinical levels. In this review, we summarize the OVs evaluated in different types of PBTs, mostly in pre-clinical studies, and we discuss the possible future direction of research in this field. In this sense, one important aspect of OVs antitumoral effect is the stimulation of an immune response against the tumor which is necessary for a complete response in preclinical immunocompetent models and in the clinic. The role of the immune system in the response of OVs needs to be evaluated in PBTs and represents an experimental challenge due to the limited immunocompetent models of these diseases available for pre-clinical research.

Results of a Policy of Fast Tapering of Steroids After Resection Surgery in Glioblastoma.

BACKGROUND: Corticosteroids are routinely used to treat brain tumors. Although steroids have an immediate clinical benefit, their use can lead to a number of relevant complications, and a negative association with overall survival has been shown in glioblastoma (GBM) patients. There is no evidence in the literature regarding the ideal dose. We assessed the use of steroids in patients with GBM after resection surgery. METHODS: This is a cohort study of 131 newly diagnosed GBM patients that underwent tumor resection surgery. Dose of steroids was as low as possible, without a formal guideline. Fifteen patients were lost at baseline (retention rate, 88.5%). Our population for analysis included 114 patients that were still at risk of death at a landmark time point 2 months after surgery. RESULTS: Within 1 month of surgery, 93.9% of patients came off steroids, and 84.7% came off steroids before 2 weeks. One month after radiotherapy, 86 (75.4%) patients remained steroid-free and 28 (24.6%) were steroid-dependent. During 2235 person-months of follow-up, we documented 101 incident deaths. After adjusting for age, sex, Karnofsky Performance Scale score, MGMT promoter methylation, and extent of tumor resection, and time to surgery, the hazard ratio for the steroid-free group of patients was 0.46 (95% confidence interval, 0.28-0.77) compared with steroid-dependent patients. CONCLUSIONS: This study provides evidence for an inverse association between the lack of steroid dependency and mortality risk in patients whose steroid dosage was rapidly tapered after surgery. After resection, most patients can stop steroids within 2 weeks and finish radiotherapy without steroids.

[3D printing in neurosurgery: a specific model for patients with craniosynostosis]. / Impresión 3D en neurocirugía: modelo específico para pacientes con craneosinostosis.

INTRODUCTION: Craniosynostosis is a rare condition and requires a personalised surgical approach, which is why we consider the use of 3D printed models beneficial in the surgical planning of this procedure. MATERIAL AND METHODS: Acrylonitrile butadiene styrene plastic skull models were designed and printed from CT images of patients between 3 and 6 months of age with craniosynostosis of different sutures. The models were used to simulate surgical procedures. RESULTS: Four models of four patients with craniosynostosis were produced: two with closure of the metopic suture and two with sagittal suture closure. The mean age of the patients was 5 months (3-6m) and the mean duration of the surgery was 286min (127-380min). The acrylonitrile butadiene styrene plastic models printed for the project proved to be optimal for the simulation of craniosynostosis surgeries, both anatomically and in terms of mechanical properties and reaction to surgical instruments. CONCLUSIONS: 3D printers have a wide range of medical applications and they offer an easy and affordable way to produce skull models. The acrylonitrile butadiene styrene material is suitable for the production of operable bone models as it faithfully reproduces the mechanical characteristics of bone tissue.

Development of a DIPG Orthotopic Model in Mice Using an Implantable Guide-Screw System.

OBJECTIVE: In this work we set to develop and to validate a new in vivo frameless orthotopic Diffuse Intrinsic Pontine Glioma (DIPG) model based in the implantation of a guide-screw system. METHODS: It consisted of a guide-screw also called bolt, a Hamilton syringe with a 26-gauge needle and an insulin-like 15-gauge needle. The guide screw is 2.6 mm in length and harbors a 0.5 mm central hole which accepts the needle of the Hamilton syringe avoiding a theoretical displacement during insertion. The guide-screw is fixed on the mouse skull according to the coordinates: 1mm right to and 0.8 mm posterior to lambda. To reach the pons the Hamilton syringe is adjusted to a 6.5 mm depth using a cuff that serves as a stopper. This system allows delivering not only cells but also any kind of intratumoral chemotherapy, antibodies or gene/viral therapies. RESULTS: The guide-screw was successfully implanted in 10 immunodeficient mice and the animals were inoculated with DIPG human cell lines during the same anesthetic period. All the mice developed severe neurologic symptoms and had a median overall survival of 95 days ranging the time of death from 81 to 116 days. Histopathological analysis confirmed tumor into the pons in all animals confirming the validity of this model. CONCLUSION: Here we presented a reproducible and frameless DIPG model that allows for rapid evaluation of tumorigenicity and efficacy of chemotherapeutic or gene therapy products delivered intratumorally to the pons.

To what extent will 5-aminolevulinic acid change the face of malignant glioma surgery?

Glioma surgery is an essential part of glioma management; however, fully achieving the goal of surgery has been uncommon. The goal of surgery is 'maximal safe resection' with the accepted target for maximal being complete resection of the contrast-enhancing tumor. This ideal result was obtained in less than 30% of cases in centers of excellence until a few years ago. The development of fluorescence-guided surgery using 5-aminolevulinic acid has initiated a radical change. Over the past 5 years, various groups have published rates of complete resection of the enhancing tumor that exceed 80%. In the coming years, as the use of the technology expands, complete resection should become a common, predictable result at many centers. Consequently, adjuvant therapies that benefit from resection could play a bigger role, resection could be incorporated as a variable in randomized trials and distant recurrence might become a more common problem.

Safety Profile of 5-Aminolevulinic Acid as a Surgical Adjunct in Clinical Practice: A Review of 207 Cases From 2008 to 2013.

BACKGROUND: 5-Aminolevulinic acid (5-ALA) is used for brain tumor identification during surgery through fluorescence. Its use is linked to side effects such as photodermatosis, anemia, or plaquetopenia. Many institutions take very strict precautions to prevent them. Our hospital's protocol mandates avoidance of direct sunlight during the first 24 hours only. METHODS: Retrospective cohort observational study of 207 consecutive patients who underwent 5-ALA-guided brain tumor resection between 2008 and 2013, and compared with a control group of 53 patients without 5-ALA. RESULTS: No skin reaction was reported. No difference was found in hemoglobin or platelet level comparisons at different points in time. There was no difference in trends within groups. Mean duration of surgery was longer in the 5-ALA group; the subgroup of patients undergoing their first surgery had a positive correlation with lower hemoglobin levels. In postoperative magnetic resonance imaging, patients in the 5-ALA group had a lower percentage of residual bleeding (19% of all patients; 17.9% in 5-ALA group and 22.7% in non-ALA [P=0.04]). Eight patients in the 5-ALA group required blood transfusion (3.9%), compared with 2 in the control group (3.8%). Four patients in the 5-ALA group required reintervention in the first 48 hours due to bleeding, although none had platelets <150,000/mL. CONCLUSIONS: Significant side effects appear to be uncommon. Blood count changes are likely multifactorial; surgical time may account for it partially, whereas 5-ALA role is not clear and may not be significant.

Involvement of miRNAs in the differentiation of human glioblastoma multiforme stem-like cells.

Glioblastoma multiforme (GBM)-initiating cells (GICs) represent a tumor subpopulation with neural stem cell-like properties that is responsible for the development, progression and therapeutic resistance of human GBM. We have recently shown that blockade of NFκB pathway promotes terminal differentiation and senescence of GICs both in vitro and in vivo, indicating that induction of differentiation may be a potential therapeutic strategy for GBM. MicroRNAs have been implicated in the pathogenesis of GBM, but a high-throughput analysis of their role in GIC differentiation has not been reported. We have established human GIC cell lines that can be efficiently differentiated into cells expressing astrocytic and neuronal lineage markers. Using this in vitro system, a microarray-based high-throughput analysis to determine global expression changes of microRNAs during differentiation of GICs was performed. A number of changes in the levels of microRNAs were detected in differentiating GICs, including over-expression of hsa-miR-21, hsa-miR-29a, hsa-miR-29b, hsa-miR-221 and hsa-miR-222, and down-regulation of hsa-miR-93 and hsa-miR-106a. Functional studies showed that miR-21 over-expression in GICs induced comparable cell differentiation features and targeted SPRY1 mRNA, which encodes for a negative regulator of neural stem-cell differentiation. In addition, miR-221 and miR-222 inhibition in differentiated cells restored the expression of stem cell markers while reducing differentiation markers. Finally, miR-29a and miR-29b targeted MCL1 mRNA in GICs and increased apoptosis. Our study uncovers the microRNA dynamic expression changes occurring during differentiation of GICs, and identifies miR-21 and miR-221/222 as key regulators of this process.