Maximizing the extent of resection and survival benefit of patients in glioblastoma surgery: High-field iMRI versus conventional and 5-ALA-assisted surgery

Glioblastoma: Clinical Presentation, Multidisciplinary Management, and Long-Term Outcomes

Glioblastoma, the most common and aggressive primary brain tumor in adults, presents a formidable challenge due to its rapid progression, treatment resistance, and poor survival outcomes. Standard care typically involves maximal safe surgical resection, followed by fractionated external beam radiation therapy and concurrent temozolomide chemotherapy. Despite these interventions, median survival remains approximately 12-15 months, with a five-year survival rate below 10%. Prognosis is influenced by factors such as patient age, molecular characteristics, and the extent of resection. Patients with IDH-mutant tumors or methylated MGMT promoters generally have improved survival, while recurrent glioblastoma is associated with a median survival of only six months, as therapies in these cases are often palliative. Innovative treatments, including TTFields, add incremental survival benefits, extending median survival to around 20.9 months for eligible patients. Symptom management-addressing seizures, headaches, and neurological deficits-alongside psychological support for patients and caregivers is essential to enhance quality of life. Emerging targeted therapies and immunotherapies, though still limited in efficacy, show promise as part of an evolving treatment landscape. Continued research and clinical trials remain crucial to developing more effective treatments. This multidisciplinary approach, incorporating diagnostics, personalized therapy, and supportive care, aims to improve outcomes and provides a hopeful foundation for advancing glioblastoma management.

Comparative efficacy of awake and asleep motor mapping in glioma surgery: A meta-analysis of 3011 patients

Standard of care in glioma surgery involves maximal-safe resection. Intraoperative stimulation mapping can improve the extent of resection in eloquent area tumors. Resection is performed during awake craniotomy (AC) or under general anesthesia (GA). Considering the advances in glioma management, an updated meta-analysis is needed. We identified studies evaluating surgical outcomes in adult patients undergoing glioma resection in motor areas, comparing AC and GA mapping until November 2023. Twenty-four observational studies and one randomized controlled trial met our inclusion criteria, adding 3011 patients. The mean extent of resection was 92.2% (95%CI = 89.9%-94.5%) for AC and 92.5% (95%CI = 89.6%-95.3%) for GA. Immediate deficit revealed a nonsignificant risk ratio (RR) of 0.96 favoring AC (95%CI = 0.66-1.41, p = 0.84). Similarly, long-term deficits showed a nonsignificant RR of 1.33 favoring GA (95%CI = 0.91-1.95, p = 0.14). Karnofsky performance score (KPS) analysis revealed a nonsignificant mean difference of 2.32 favoring GA (95%CI = -6.10-10.73, p = 0.59). Intraoperative stimulation-induced seizures analysis yielded a nonsignificant RR of 0.73 (95% CI = 0.27-1.97, p = 0.53) favoring AC. Postoperative seizure analysis showed a significant RR of 0.64 (95% CI = 0.44-0.94, p = 0.02) favoring AC. This meta-analysis suggests that AC and GA are comparable approaches to maximize extent of resection and achieve safe resection in eloquent glioma surgery. These findings can offer guidance to neurosurgeons in the decision-making process.

A Phase 2 Sensitivity and Selectivity Study of High-Dose 5-Aminolevulinic Acid in Adult Patients Undergoing Resection of a Newly Diagnosed or Recurrent Glioblastoma

BACKGROUND AND OBJECTIVES

The utility of oral 5-aminolevulinic acid (5-ALA)/protoporphyrin fluorescence for the resection of high-grade gliomas is well documented, but the problem of false-negative observations remains. This study compares high-grade glioma visualization with low/standard dose 5-ALA (<30 mg/kg) to high-dose 5-ALA (>40 mg/kg) to see if by using this higher dose, it is possible to reduce the rate of false-negative observations without increasing the rate of false-positive (FP) observations and therefore increase the sensitivity.

METHODS

This is a prospective study of consecutive patients with radiological evidence of presumed high-grade glioma. We reviewed the data from patients who received preoperative low/standard doses and patients who received a preoperative high dose of 5-ALA. Adverse events, dose to observation time, intensity of tumor fluorescence, and results of biopsies in areas of tumor and tumor bed under deep blue light were recorded.

RESULTS

A total of 22 patients with high-grade glioma received a dose >40 mg/kg (high-dose) and 9 patients received <30 mg/kg (low/standard dose). There were no serious adverse events related to 5-ALA in any subject. There was a very high sensitivity and specificity of 5-ALA for the presence of tumor in both groups. There were no FP observations (fluorescence with no tumor) in either group. The specificity and the positive predictive value were 100% in both groups. The sensitivity and the negative predictive value were 53.3% and 30.0% in the low/standard dose group and 59.5% and 31.8% in the high-dose group, respectively.

CONCLUSION

High-dose oral 5-aminolevulinic/protoporphyrin fluorescence is a safe and effective aid to the intraoperative detection of high-grade gliomas with high sensitivity and specificity. False-negative observations with a high dose do not seem to be less than that with a low/standard dose. The rate of FP observations with both groups remains very low.

Observations from the first 100 cases of intraoperative MRI - experiences, trends and short-term outcomes

BACKGROUND

We sought to analyze, in well-defined clinical setting, the first 100 patients treated at the intraoperative MRI (iMRI) hybrid surgical theatre at our facility in a population-based setting to evaluate which pathologies are best approached with iMRI assisted surgeries, as this is not yet clearly defined.

METHODS

Patients undergoing surgery in the 3T iMRI hybrid surgical theatre at our neurosurgical department between December 2017 to May 2021 were included after informed consent. Demographic, clinical, surgical, histological, radiological and outcome parameters, as well as variables related to iMRI, were retrospectively collected and analyzed. Patients were subdivided into adult and pediatric cohorts.

RESULTS

Various neurosurgical procedures were performed; resection of tumors and epileptic foci, endoscopic skull base procedures including pituitary lesions, deep brain stimulation (DBS) and laser interstitial thermal therapy (LITT). In total, 41 patients were pediatric. An iMRI scan was carried out in 96% of cases and led to continuation of surgery in 50% of cases, mainly due to visualized remaining pathological tissue (95.2%). Median time to iMRI from intubation was 280 min and median total duration of surgery was 445 min. The majority of patients experienced no postoperative complications (70%), 13 patients suffered permanent postoperative deficits, predominantly visual.

CONCLUSION

Herein, we demonstrate the first 100 patients undergoing neurosurgery aided by iMRI at our facility since introduction. Indications for surgery differed between pediatric and adult patients. The iMRI was utilized for tumor surgeries, particularly adult low-grade gliomas and pediatric tumors, as well as for epilepsy surgery and DBS. In this heterogenous population, iMRI led to continuation of surgery in 50%. To establish the benefit in maximizing the extent of resection in these brain pathologies future studies are recommended.

CLINICAL TRIAL NUMBER

Not applicable.

Intraoperative magnetic resonance imaging in glioma surgery: a single-center experience

PURPOSE

To investigate the effect of intraoperative magnetic resonance imaging (Io MRI) on overall and progression-free survival (OS and PFS), on the extent of resection (EOR) in patients with glioma, and impact of the radiological diagnosis on the decision to continue the surgery when a residual mass was detected on Io MRI.

METHODS

The study comprised 153 glioma patients who received surgical treatment between 2013 and 2023. One-hundred twenty-five of them had Io MRI guidance during surgery. The remainder 28 patients constituted the control group who did not undergo Io MRI. All patients' age at surgery, gender, initial radiological diagnosis, primary tumor localization, EOR, last histopathological diagnosis, and the follow-up periods were recorded.

RESULTS

The rate of tumor recurrence in Io MRI cases was significantly lower compared to the cases in the control group (p < .0001). It was decided to continue the operation in 45 Io MRI applied cases. This raised the gross total resection (GTR) rate from 33.6% to 49.6% in the Io MRI group. The frequency of GTR was significantly higher in patients with an initial radiological diagnosis of low grade glioma than those with high grade glioma. The shortest OS was seen in occipital gliomas.

CONCLUSION

In this study, the convenience provided by the high-field MRI device was explored and proven both in reducing the tumor burden, increasing the PFS, and providing the surgeon with a maximal resection in the first operation.

Intraoperative ultrasound for surgical resection of high-grade glioma and glioblastoma: a meta-analysis of 732 patients

PURPOSE

Here, we conducted a meta-analysis to explore the use of intraoperative ultrasound (iUS)-guided resection in patients diagnosed with high-grade glioma (HGG) or glioblastoma (GBM). Our aim was to determine whether iUS improves clinical outcomes compared to conventional neuronavigation (CNN).

METHODS

Databases were searched until April 21, 2023 for randomized controlled trials (RCTs) and observational cohort studies that compared surgical outcomes for patients with HGG or GBM with the use of either iUS in addition to standard approach or CNN. The primary outcome was overall survival (OS). Secondary outcomes include volumetric extent of resection (EOR), gross total resection (GTR), and progression-free survival (PFS). Outcomes were analyzed by determining pooled relative risk ratios (RR), mean difference (MD), and standardized mean difference (SMD) using random-effects model.

RESULTS

Of the initial 867 articles, only 7 articles specifically met the inclusion criteria (1 RCT and 6 retrospective cohorts). The analysis included 732 patients. Compared to CNN, the use of iUS was associated with higher OS (SMD = 0.26,95%CI=[0.12,0.39]) and GTR (RR = 2.02; 95% CI=[1.31,3.1]) for both HGG and GBM. There was no significant difference in PFS or EOR.

CONCLUSION

The use of iUS in surgical resections for HGG and GBM can improve OS and GTR compared to CNN, but it did not affect PFS. These results suggest that iUS reduces mortality associated with HGG and GBM but not the risk of recurrence. These results can provide valuable cost-effective interventions for neurosurgeons in HGG and GBM surgery.

Glioblastoma Therapy: Past, Present and Future

Glioblastoma (GB) stands out as the most prevalent and lethal form of brain cancer. Although great efforts have been made by clinicians and researchers, no significant improvement in survival has been achieved since the Stupp protocol became the standard of care (SOC) in 2005. Despite multimodality treatments, recurrence is almost universal with survival rates under 2 years after diagnosis. Here, we discuss the recent progress in our understanding of GB pathophysiology, in particular, the importance of glioma stem cells (GSCs), the tumor microenvironment conditions, and epigenetic mechanisms involved in GB growth, aggressiveness and recurrence. The discussion on therapeutic strategies first covers the SOC treatment and targeted therapies that have been shown to interfere with different signaling pathways (pRB/CDK4/RB1/P16ink4, TP53/MDM2/P14arf, PI3k/Akt-PTEN, RAS/RAF/MEK, PARP) involved in GB tumorigenesis, pathophysiology, and treatment resistance acquisition. Below, we analyze several immunotherapeutic approaches (i.e., checkpoint inhibitors, vaccines, CAR-modified NK or T cells, oncolytic virotherapy) that have been used in an attempt to enhance the immune response against GB, and thereby avoid recidivism or increase survival of GB patients. Finally, we present treatment attempts made using nanotherapies (nanometric structures having active anti-GB agents such as antibodies, chemotherapeutic/anti-angiogenic drugs or sensitizers, radionuclides, and molecules that target GB cellular receptors or open the blood-brain barrier) and non-ionizing energies (laser interstitial thermal therapy, high/low intensity focused ultrasounds, photodynamic/sonodynamic therapies and electroporation). The aim of this review is to discuss the advances and limitations of the current therapies and to present novel approaches that are under development or following clinical trials.

Intraoperative MRI-Guided Resection Is Not Superior to 5-Aminolevulinic Acid Guidance in Newly Diagnosed Glioblastoma: A Prospective Controlled Multicenter Clinical Trial

PURPOSE

Prospective data suggested a superiority of intraoperative MRI (iMRI) over 5-aminolevulinic acid (5-ALA) for achieving complete resections of contrast enhancement in glioblastoma surgery. We investigated this hypothesis in a prospective clinical trial and correlated residual disease volumes with clinical outcome in newly diagnosed glioblastoma.

METHODS

This is a prospective controlled multicenter parallel-group trial with two center-specific treatment arms (5-ALA and iMRI) and blinded evaluation. The primary end point was complete resection of contrast enhancement on early postoperative MRI. We assessed resectability and extent of resection by an independent blinded centralized review of preoperative and postoperative MRI with 1-mm slices. Secondary end points included progression-free survival (PFS) and overall survival (OS), patient-reported quality of life, and clinical parameters.

RESULTS

We recruited 314 patients with newly diagnosed glioblastomas at 11 German centers. A total of 127 patients in the 5-ALA and 150 in the iMRI arm were analyzed in the as-treated analysis. Complete resections, defined as a residual tumor ≤0.175 cm³, were achieved in 90 patients (78%) in the 5-ALA and 115 (81%) in the iMRI arm (P = .79). Incision-suture times (P < .001) were significantly longer in the iMRI arm (316 v 215 [5-ALA] minutes). Median PFS and OS were comparable in both arms. The lack of any residual contrast enhancing tumor (0 cm³) was a significant favorable prognostic factor for PFS (P < .001) and OS (P = .048), especially in methylguanine-DNA-methyltransferase unmethylated tumors (P = .006).

CONCLUSION

We could not confirm superiority of iMRI over 5-ALA for achieving complete resections. Neurosurgical interventions in newly diagnosed glioblastoma shall aim for safe complete resections with 0 cm³ contrast-enhancing residual disease, as any other residual tumor volume is a negative predictor for PFS and OS.

Surgical Management and Advances in the Treatment of Glioma

The care of patients with both high-grade glioma and low-grade glioma necessitates an interdisciplinary collaboration between neurosurgeons, neuro-oncologists, neurologists and other practitioners. In this review, we aim to detail the considerations, approaches and advances in the neurosurgical care of gliomas. We describe the impact of extent-of-resection in high-grade and low-grade glioma, with particular focus on primary and recurrent glioblastoma. We address advances in surgical methods and adjunct technologies such as intraoperative imaging and fluorescence guided surgery that maximize extent-of-resection while minimizing the potential for iatrogenic neurological deficits. Finally, we review surgically-mediated therapies other than resection and discuss the role of neurosurgery in emerging paradigm-shifts in inter-disciplinary glioma management such as serial tissue sampling and "window of opportunity trials".

Resection of Eloquent Located Brain Tumors by Mapping Only-A Feasibility Study

BACKGROUND

Patients with eloquently located cerebral lesions require surgery that usually employs mapping and monitoring techniques for the preservation of motor and language function. However, in many cases, mapping only might be sufficient, reducing the need for technical and personnel logistics. Here, we report our experiences using a device that can be operated by the surgeon independently, providing mapping techniques but omitting monitoring techniques.

METHODS

For monopolar and bipolar cortical/subcortical stimulation, pre-set programs were available and intraoperatively used-two enabling EMG real-time tracking of eight muscles for monopolar (cortical/subcortical) mapping, and two programs for 60 Hz stimulation, one with EMG and one without. Motor mapping was performed under continuous observation of the screened EMG signal and acoustic feedback by the surgeon. For the 60 Hz stimulation, a standard bipolar stimulation probe was connected through a second port. The preoperative application of the subdermal EMG needles, as well as the intraoperative handling of the device, were performed by the surgeons independently. Postoperatively, an evaluation of the autonomous handling and feasibility of the device for the chosen test parameters was conducted.

RESULTS

From 04/19-09/21, 136 procedures in patients with eloquently located cerebral lesions were performed by using the "mapping-only" device. Mapping was performed in 82% of the monopolar cases and in 42% of the bipolar cases. Regarding the setup and sufficiency for the cortical/subcortical mapping, the device was evaluated as independently usable for motor and language mapping in 129 procedures (95%). Gross total resection was achieved, or functional limit throughout resection was reached, in 79% of the patients. 13 patients postoperatively suffered from a new neurological deficit. At the 3-6-month follow-up, three patients showed persistent deficit (2%). All of them had language disturbances. The setup time for the device was less than 7 min.

CONCLUSIONS

The device was evaluated as sufficient in over 90% of cases concerning monopolar and bipolar mapping, and the setup and handling was sufficient in all patients. With the present data we show that in well-selected cases, a very simple system providing mapping only is sufficient to achieve gross total resection with the preservation of functionality.

Increasing Patient Safety and Treatment Quality by Using Intraoperative MRI for Organ-Preserving Tumor Resection and High-Dose Rate Brachytherapy in Children with Bladder/Prostate and Perianal Rhabdomyosarcoma

In children with bladder/prostate (BP) and perianal rhabdomyosarcoma (RMS), we use a hybrid treatment concept for those suitable, combining organ-preserving tumor resection and high-dose rate brachytherapy (HDR-BT). This treatment concept has been shown to improve outcomes. However, it is associated with specific challenges for the clinicians. The exact position of the tubes for BT is a prerequisite for precise radiotherapy. It can finally be determined only with an MRI or CT scan. We evaluated the use of an intraoperative MRI (iMRI) to control the position of the BT tubes and for radiotherapy planning in all patients with BP and perianal RMS who received the above-mentioned combination therapy in our department since January 2021. iMRI was used in 12 children. All tubes were clearly localized. No adverse events occurred. In all 12 children, radiotherapy could be started on time. In a historical cohort without iMRI, this was not possible in 3 out of 20 children. The use of iMRI in children with BP and perianal RMS improved patient safety and treatment quality. This technology has proven to be successful for the patient population we have defined and has become a standard procedure in our institution.

Lipid-Based Nanocarriers in the Treatment of Glioblastoma Multiforme (GBM): Challenges and Opportunities

Glioblastoma multiforme (also known as glioblastoma; GBM) is one of the most malignant types of brain tumors that occurs in the CNS. Treatment strategies for glioblastoma are majorly comprised of surgical resection, radiotherapy, and chemotherapy along with combination therapy. Treatment of GBM is itself a tedious task but the involved barriers in GBM are one of the main impediments to move one step closer to the treatment of GBM. Basically, two of the barriers are of utmost importance in this regard, namely blood brain barrier (BBB) and blood brain tumor barrier (BBTB). This review will address different challenges and barriers in the treatment of GBM along with their etiology. The role and recent progress of lipid-based nanocarriers like liposomes, solid lipid nanocarriers (SLNs), nanostructured lipid carriers (NLCs), lipoplexes, and lipid hybrid carriers in the effective management of GBM will be discussed in detail.

Surgical management of Glioma Grade 4: technical update from the neuro-oncology section of the Italian Society of Neurosurgery (SINch®): a systematic review

PURPOSE

The extent of resection (EOR) is an independent prognostic factor for overall survival (OS) in adult patients with Glioma Grade 4 (GG4). The aim of the neuro-oncology section of the Italian Society of Neurosurgery (SINch®) was to provide a general overview of the current trends and technical tools to reach this goal.

METHODS

A systematic review was performed. The results were divided and ordered, by an expert team of surgeons, to assess the Class of Evidence (CE) and Strength of Recommendation (SR) of perioperative drugs management, imaging, surgery, intraoperative imaging, estimation of EOR, surgery at tumor progression and surgery in elderly patients.

RESULTS

A total of 352 studies were identified, including 299 retrospective studies and 53 reviews/meta-analysis. The use of Dexamethasone and the avoidance of prophylaxis with anti-seizure medications reached a CE I and SR A. A preoperative imaging standard protocol was defined with CE II and SR B and usefulness of an early postoperative MRI, with CE II and SR B. The EOR was defined the strongest independent risk factor for both OS and tumor recurrence with CE II and SR B. For intraoperative imaging only the use of 5-ALA reached a CE II and SR B. The estimation of EOR was established to be fundamental in planning postoperative adjuvant treatments with CE II and SR B and the stereotactic image-guided brain biopsy to be the procedure of choice when an extensive surgical resection is not feasible (CE II and SR B).

CONCLUSIONS

A growing number of evidences evidence support the role of maximal safe resection as primary OS predictor in GG4 patients. The ongoing development of intraoperative techniques for a precise real-time identification of peritumoral functional pathways enables surgeons to maximize EOR minimizing the post-operative morbidity.

Review of Intraoperative Adjuncts for Maximal Safe Resection of Gliomas and Its Impact on Outcomes

Maximal safe resection is the mainstay of treatment in the neurosurgical management of gliomas, and preserving functional integrity is linked to favorable outcomes. How these modalities differ in their effectiveness on the extent of resection (EOR), survival, and complications remains unknown. A systematic literature search was performed with the following inclusion criteria: published between 2005 and 2022, involving brain glioma surgery, and including one or a combination of intraoperative modalities: intraoperative magnetic resonance imaging (iMRI), awake/general anesthesia craniotomy mapping (AC/GA), fluorescence-guided imaging, or combined modalities. Of 525 articles, 464 were excluded and 61 articles were included, involving 5221 glioma patients, 7(11.4%) articles used iMRI, 21(36.8%) used cortical mapping, 15(24.5%) used 5-aminolevulinic acid (5-ALA) or fluorescein sodium, and 18(29.5%) used combined modalities. The heterogeneity in reporting the amount of surgical resection prevented further analysis. Progression-free survival/overall survival (PFS/OS) were reported in 18/61(29.5%) articles, while complications and permanent disability were reported in 38/61(62.2%) articles. The reviewed studies demonstrate that intraoperative adjuncts such as iMRI, AC/GA mapping, fluorescence-guided imaging, and a combination of these modalities improve EOR. However, PFS/OS were underreported. Combining multiple intraoperative modalities seems to have the highest effect compared to each adjunct alone.

Is intraoperative ultrasound more efficient than magnetic resonance in neurosurgical oncology? An exploratory cost-effectiveness analysis

Objective

Intraoperative imaging is a chief asset in neurosurgical oncology, it improves the extent of resection and postoperative outcomes. Imaging devices have evolved considerably, in particular ultrasound (iUS) and magnetic resonance (iMR). Although iUS is regarded as a more economically convenient and yet effective asset, no formal comparison between the efficiency of iUS and iMR in neurosurgical oncology has been performed.

Methods

A cost-effectiveness analysis comparing two single-center prospectively collected surgical cohorts, classified according to the intraoperative imaging used. iMR (2013-2016) and iUS (2021-2022) groups comprised low- and high-grade gliomas, with a maximal safe resection intention. Units of health gain were gross total resection and equal or increased Karnofsky performance status. Surgical and health costs were considered for analysis. The incremental cost-effectiveness ratio (ICER) was calculated for the two intervention alternatives. The cost-utility graphic and the evolution of surgical duration with the gained experience were also analyzed.

Results

50 patients followed an iMR-assisted operation, while 17 underwent an iUS-guided surgery. Gross total resection was achieved in 70% with iMR and in 60% with iUS. Median postoperative Karnofsky was similar in both group (KPS 90). Health costs were € 3,220 higher with iMR, and so were surgical-related costs (€ 1,976 higher). The ICER was € 322 per complete resection obtained with iMR, and € 644 per KPS gained or maintained with iMR. When only surgical-related costs were analyzed, ICER was € 198 per complete resection with iMR and € 395 per KPS gained or maintained.

Conclusion

This is an unprecedented but preliminary cost-effectiveness analysis of the two most common intraoperative imaging devices in neurosurgical oncology. iMR, although being costlier and time-consuming, seems cost-effective in terms of complete resection rates and postoperative performance status. However, the differences between both techniques are small. Possibly, iMR and iUS are complementary aids during the resection: iUS real-time images assist while advancing towards the tumor limits, informing about the distance to relevant landmarks and correcting neuronavigation inaccuracy due to brain shift. Yet, at the end of resection, it is the iMR that reliably corroborates whether residual tumor remains.

Updates in IDH-Wildtype Glioblastoma

Glioblastoma is the most aggressive primary brain tumor with a poor prognosis. The 2021 WHO CNS5 classification has further stressed the importance of molecular signatures in diagnosis although therapeutic breakthroughs are still lacking. In this review article, updates on the current and novel therapies in IDH-wildtype GBM will be discussed.

Surgical Treatment of Glioblastoma: State-of-the-Art and Future Trends

Glioblastoma (GBM) is a highly aggressive disease and is associated with poor prognosis despite treatment advances in recent years. Surgical resection of tumor remains the main therapeutic option when approaching these patients, especially when combined with adjuvant radiochemotherapy. In the present study, we conducted a comprehensive literature review on the state-of-the-art and future trends of the surgical treatment of GBM, emphasizing topics that have been the object of recent study.

The Intraoperative Utilization of Multimodalities Could Improve the Prognosis of Adult Glioblastoma: A Single-Center Observational Study

OBJECTIVE

In recent years, numerous neurosurgical multimodal techniques have been utilized to maximize tumor resection safely and effectively. However, the synergetic effects of neurosurgical multimodalities on the survival of glioblastoma patients remain unclear. This study evaluated the role of intraoperative utilization of multimodalities in glioblastoma patients.

METHODS

Data of 912 adult patients with glioblastoma were obtained from the Huashan Glioma Registry. The utilization of fewer than 2 (multimodality value < 2) intraoperative multimodal techniques was defined as the nonmultimodal group. In contrast, the utilization of 2 or more (multimodality value ≥ 2) intraoperative multimodal techniques was regarded as the multimodal group. The prognosis of the 2 cohorts was compared and further stratified based on the diagnosis date (2010-2014 or 2015-2019) to reveal the role of the application of multimodal techniques.

RESULTS

The median overall survival (OS) and progression-free survival of glioblastoma patients were 17.70 months and 12.03 months, respectively. The OS time of the multimodal group was noticeably longer than that of the nonmultimodal group (21.0 months vs. 16.0 months, P < 0.001). Multimodal techniques were more frequently applied in surgery in the 2015-2019 group than in the 2010-2014 group. The popularity of multimodal techniques contributed to significant improvement in the prognosis of glioblastoma patients from 2010-2014 to 2015-2019 (OS, 16.0 months vs. 22.0 months, P < 0.001).

CONCLUSIONS

This study indicated that the utilization of intraoperative multimodal techniques improved the extent of resection and elevated the survival for adult glioblastoma patients.

Nomograms for prognostic risk assessment in glioblastoma multiforme: Applications and limitations

Glioblastoma multiforme (GBM) is the most common and aggressive form of brain cancer. Prognosis evaluation is of great significance in guiding individualized treatment and monitoring of GBM. By integrating different prognostic variables, nomograms simplify the statistical risk prediction model into numerical estimates for death or recurrence, and are hence widely applied in prognosis prediction. In the past two decades, the application of high-throughput profiling technology and the establishment of TCGA database and other public data deposits have provided opportunities to identify cancer-related molecules and prognostic biomarkers. As a result, both molecular features and clinical characteristics of cancer have been reported to be the key factors in nomogram model construction. This article comprehensively reviewed 35 studies of GBM nomograms, analyzed the present situation of GBM nomograms, and discussed the role and significance of nomograms in personalized risk assessment and clinical treatment decision-making. To facilitate the application of nomograms in the prognostic prediction of GBM patients, a website has been established for the online access of nomograms based on the studies of this review, which is called Consensus Nomogram Spectrum for Glioblastoma (CNSgbm) and is accessible through https://bioinfo.henu.edu.cn/nom/NomList.jsp.

The Extent of Resection in Gliomas-Evidence-Based Recommendations on Methodological Aspects of Research Design

OBJECTIVE

Modern neurosurgery has established maximal safe resection as a cornerstone in the management of diffuse gliomas. Evaluation of the extent of resection (EOR), and its association with certain outcomes or interventions, heavily depends on an adequate methodology to draw strong conclusions. We aim to identify weaknesses and limitations that may threaten the internal validity and generalizability of studies involving the EOR in patients with glioma and to suggest methodological recommendations that may help mitigate these threats.

METHODS

A systematic search was performed by querying PubMed, Web of Science, and Scopus since inception to April 30, 2021 using PICOS/PRISMA guidelines. Articles were then screened to identify high-impact studies evaluating the EOR in patients diagnosed with diffuse gliomas in accordance with predefined criteria. We identify common weakness and limitations during the evaluation of the EOR in the selected studies and then delineate potential methodological recommendations for future endeavors dealing with the EOR.

RESULTS

We identified 31 high-impact studies and found several research design issues including inconsistencies regarding EOR terminology, measurement, data collection, analysis, and reporting. Although some of these issues were related to now outdated reporting standards, many were still present in recent publications and deserve attention in contemporary and future research.

CONCLUSIONS

There is a current need to focus more attention to the methodological aspects of glioma research. Methodological inconsistencies may introduce weaknesses into the internal validity of the studies and hamper comparative analysis of cohorts from different institutions. We hope our recommendations will eventually help develop stronger methodological designs in future research endeavors.

Use of intraoperative MRI for resection of intracranial tumors: A nationwide analysis of short-term outcomes

OBJECTIVE

Recent evidence supports the use of intraoperative MRI (iMRI) during resection of intracranial tumors due to its demonstrated efficacy and clinical benefit. Though many single-center investigations have been conducted, larger nationwide outcomes have yet to be characterized.

METHODS

We used the American College of Surgeons National Surgical Quality Improvement Program database to examine baseline characteristics and 30-day postoperative outcomes among patients undergoing craniotomy for tumor resection with and without iMRI. Comparisons between outcomes were accomplished after propensity matching using chi-square tests for categorical variables and Welch two-sample t-tests for continuous variables.

RESULTS

A total of 38,003 patients met inclusion criteria. Of this population, 54 (0.1%) received iMRI, while 37,949 (99.9%) did not receive iMRI. After propensity score matching, the resulting groups consisted of an iMRI group (n = 54) and a matched non-iMRI group (n = 54). Procedures involving iMRI were associated with significantly increased operation length compared to those without (p < 0.01). Length of hospital stay was higher in patients without iMRI, with this difference trending towards significance (p = 0.05) in the unmatched comparison. Patients undergoing craniotomy without iMRI had a higher rate of readmission (p = 0.04). There was no significant difference in occurrence of other adverse events between the two patient groups.

CONCLUSION

Despite increasing operative length, iMRI is not associated with higher infection rate and may have a clinical benefit associated with reducing readmissions and a trend towards reducing inpatient length of stay. Additional nationwide analyses including more iMRI patients would provide further insight into the strength of these findings.

Intraoperative MR Imaging during Glioma Resection

One of the major issues in the surgical treatment of gliomas is the concern about maximizing the extent of resection while minimizing neurological impairment. Thus, surgical planning by carefully observing the relationship between the glioma infiltration area and eloquent area of the connecting fibers is crucial. Neurosurgeons usually detect an eloquent area by functional MRI and identify a connecting fiber by diffusion tensor imaging. However, during surgery, the accuracy of neuronavigation can be decreased due to brain shift, but the positional information may be updated by intraoperative MRI and the next steps can be planned accordingly. In addition, various intraoperative modalities may be used to guide surgery, including neurophysiological monitoring that provides real-time information (e.g., awake surgery, motor-evoked potentials, and sensory evoked potential); photodynamic diagnosis, which can identify high-grade glioma cells; and other imaging techniques that provide anatomical information during the surgery. In this review, we present the historical and current context of the intraoperative MRI and some related approaches for an audience active in the technical, clinical, and research areas of radiology, as well as mention important aspects regarding safety and types of devices.

Intraoperative 5-ALA fluorescence-guided resection of high-grade glioma leads to greater extent of resection with better outcomes: a systematic review

IMPORTANCE

High-grade gliomas (HGG) are the most aggressive and common malignant brain tumors in adults. They have a dismally fatal prognosis. Even if gross total resection of the enhancing tumor is achieved, inevitably, invading tumor cells that are indistinguishable to the un-aided eye are left behind, which eventually leads to tumor recurrence. 5-aminolevulinic acid (5-ALA) is an increasingly utilized intraoperative fluorescent imaging agent for patients with HGG. It enhances visualization of HGG tissue. Despite early promising randomized clinical trial data suggesting a survival benefit for 5-ALA-guided surgery, the growing body of literature must be analyzed to confirm efficacy on patient outcomes.

OBJECTIVE

To perform a systematic review of the literature to evaluate whether there is a beneficial effect upon survival and extent of resection due to the utilization of 5-ALA in HGG surgery.

EVIDENCE REVIEW

Literature regarding 5-ALA usage in HGG surgery was reviewed according to the PRISMA guidelines. Two databases, PubMed and SCOPUS, were searched for assorted combinations of the keywords "5-ALA," "high-grade glioma," "5-aminolevulinic acid," and "resection" in July 2020 for case reports and retrospective, prospective, and randomized clinical trials assessing and analyzing 5-ALA intraoperative use in patients with HGG. Entailed studies on PubMed and SCOPUS were found for screening using a snowball search technique upon the initially searched papers. Systematic reviews and meta-analyses were excluded from our PRISMA table.

FINDINGS

3756 previously published studies were screened, 536 of which were further evaluated, and ultimately 45 were included in our systematic review. There were no date restrictions on the screened publications. Our literature search was finalized on July 16, 2020. We found an observed increase in the overall survival (OS) and progression-free survival (PFS) of the 5-ALA group compared to the white light group, as well as an observed increase in the OS and PFS of complete resections compared to incomplete resections. Of the studies that directly compared the use of 5-ALA to white light (13 of the total analyzed 45, or 28.9%), 5-ALA lead to a better PFS and OS in 88.4 and 67.5% of patients, respectively. When the studies that reported postoperative neurologic outcomes of surgeries using 5-ALA vs. white light were analyzed, 42.2% of subjects demonstrated 5-ALA use was associated with less post-op neurological deficits, whereas 34.5% demonstrated no difference between 5-ALA and without. 23.3% of studies showed that intraoperative 5-ALA guided surgeries lead to more post-op neurological deficits.

CONCLUSIONS AND RELEVANCE

Utilization of 5-ALA was found to be associated with a greater extent of resection in HGG surgeries, as well as longer OS and PFS. Postop neurologic deficit rates were mixed and inconclusive when comparing 5-ALA groups to white light groups. 5-ALA is a useful surgical adjunct for resection of HGG when patient safety is preserved.

Multifocal glioblastoma multiform with “encephalitis-like presentation” : a case report

Background

Glioblastoma multiform is the most common and aggressive type of primary malignant tumor that affects the central nervous system in adults. It clinically presents with seizures, headache, and/or progressive focal neurological deficits. Radiologically, glioblastoma multiform appears as a single distinguishable, large heterogeneous lesion affecting the cerebrum with characteristic central necrosis, marginal enhancement, and surrounding vasogenic edema. This article describes a patient that exhibited an atypical clinical presentation of multifocal glioblastoma multiform with misleading early radiological features that simulated herpetic encephalitis.

Results

A 66-year-old female that presented with left-sided hemiparesis and left partial motor seizures underwent multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) scans. A cerebrospinal fluid (CSF) polymerase chain reaction (PCR) test was also performed to screen for herpes simplex virus 1 (HSV-1).

Conclusions

The early stages of glioblastoma may manifest as symptoms typical to encephalitis, which can delay diagnosis and treatment. Therefore, early diagnosis and identification of atypical glioblastoma multiform presentations, as reported in this article, are essential.

Near-Infrared Imaging with Second-Window Indocyanine Green in Newly Diagnosed High-Grade Gliomas Predicts Gadolinium Enhancement on Postoperative Magnetic Resonance Imaging

PURPOSE

Intraoperative molecular imaging with tumor-targeting fluorophores offers real-time detection of neoplastic tissue. The second window indocyanine green (SWIG) technique relies on passive accumulation of indocyanine green (ICG), a near-infrared fluorophore, in neoplastic tissues. In this study, we explore the ability of SWIG to detect neoplastic tissue and to predict postoperative magnetic resonance imaging (MRI) findings intraoperatively.

PROCEDURES

Retrospective data were collected from 36 patients with primary high-grade gliomas (HGG) enrolled as part of a larger trial between October 2014 and October 2018. Patients received systemic ICG infusions at 2.5-5 mg/kg 24 h preoperatively. Near-infrared fluorescence was recorded throughout the case and from biopsy specimens. The presence/location of residual SWIG signal after resection was compared to the presence/location of residual gadolinium enhancement on postoperative MRI. The extent of resection was not changed based on near-infrared imaging.

RESULTS

All 36 lesions demonstrated strong near-infrared fluorescence (signal-to-background = 6.8 ± 2.2) and 100 % of tumors reaching the cortex were visualized before durotomy. In 78 biopsy specimens, near-infrared imaging demonstrated higher sensitivity and accuracy than white light for diagnosing neoplastic tissue intraoperatively. Furthermore, near-infrared imaging predicted gadolinium enhancement on postoperative MRI with 91 % accuracy, with visualization of residual enhancement as small as 0.3 cm³. Patients with no residual near-infrared signal after resection were significantly more likely to have complete resection on postoperative MRI (p value < 0.0001).

CONCLUSIONS

Intraoperative imaging with SWIG demonstrates highly sensitive detection of HGG tissue in real time. Furthermore, post-resection near-infrared imaging correlates with postoperative MRI. Overall, our findings suggest that SWIG can provide surgeons with MRI-like results in real time, potentially increasing resection rates.

Intraoperative MRI for newly diagnosed supratentorial glioblastoma: a multicenter-registry comparative study to conventional surgery

OBJECTIVE

Intraoperative MRI (iMRI) is used in the surgical treatment of glioblastoma, with uncertain effects on outcomes. The authors evaluated the impact of iMRI on extent of resection (EOR) and overall survival (OS) while controlling for other known and suspected predictors.

METHODS

A multicenter retrospective cohort of 640 adult patients with newly diagnosed supratentorial glioblastoma who underwent resection was evaluated. iMRI was performed in 332/640 cases (51.9%). Reviews of MRI features and tumor volumetric analysis were performed on a subsample of cases (n = 286; 110 non-iMRI, 176 iMRI) from a single institution.

RESULTS

The median age was 60.0 years (mean 58.5 years, range 20.5-86.3 years). The median OS was 17.0 months (95% CI 15.6-18.4 months). Gross-total resection (GTR) was achieved in 403/640 cases (63.0%). Kaplan-Meier analysis of 286 cases with volumetric analysis for EOR (grouped into 100%, 95%-99%, 80%-94%, and 50%-79%) showed longer OS for 100% EOR compared to all other groups (p < 0.01). Additional resection after iMRI was performed in 104/122 cases (85.2%) with initial subtotal resection (STR), leading to a 6.3% mean increase in EOR and a 2.2-cm3 mean decrease in tumor volume. For iMRI cases with volumetric analysis, the GTR rate increased from 54/176 (30.7%) on iMRI to 126/176 (71.5%) postoperatively. The EOR was significantly higher in the iMRI group for intended GTR and STR groups (p = 0.02 and p < 0.01, respectively). Predictors of GTR on multivariate logistic regression included iMRI use and intended GTR. Predictors of shorter OS on multivariate Cox regression included older age, STR, isocitrate dehydrogenase 1 (IDH1) wild type, no O 6-methylguanine DNA methyltransferase (MGMT) methylation, and no Stupp therapy. iMRI was a significant predictor of OS on univariate (HR 0.82, 95% CI 0.69-0.98; p = 0.03) but not multivariate analyses. Use of iMRI was not associated with an increased rate of new permanent neurological deficits.

CONCLUSIONS

GTR increased OS for patients with newly diagnosed glioblastoma after adjusting for other prognostic factors. iMRI increased EOR and GTR rate and was a significant predictor of GTR on multivariate analysis; however, iMRI was not an independent predictor of OS. Additional supporting evidence is needed to determine the clinical benefit of iMRI in the management of glioblastoma.

Simulation of surgery for supratentorial gliomas in virtual reality using a 3D volume rendering technique: a poor man's neuronavigation

OBJECTIVE

Different techniques of performing image-guided neurosurgery exist, namely, neuronavigation systems, intraoperative ultrasound, and intraoperative MRI, each with its limitations. Except for ultrasound, other methods are expensive. Three-dimensional virtual reconstruction and surgical simulation using 3D volume rendering (VR) is an economical and excellent technique for preoperative surgical planning and image-guided neurosurgery. In this article, the authors discuss several nuances of the 3D VR technique that have not yet been described.

METHODS

The authors included 6 patients with supratentorial gliomas who underwent surgery between January 2019 and March 2021. Preoperative clinical data, including patient demographics, preoperative planning details (done using the VR technique), and intraoperative details, including relevant photos and videos, were collected. RadiAnt software was used for generating virtual 3D images using the VR technique on a computer running Microsoft Windows.

RESULTS

The 3D VR technique assists in glioma surgery with a preoperative simulation of the skin incision and craniotomy, virtual cortical surface marking and navigation for deep-seated gliomas, preoperative visualization of morbid cortical surface and venous anatomy in surfacing gliomas, identifying the intervenous surgical corridor in both surfacing and deep-seated gliomas, and pre- and postoperative virtual 3D images highlighting the exact spatial geometric residual tumor location and extent of resection for low-grade gliomas (LGGs).

CONCLUSIONS

Image-guided neurosurgery with the 3D VR technique using RadiAnt software is an economical, easy-to-learn, and user-friendly method of simulating glioma surgery, especially in resource-constrained countries where expensive neuronavigation systems are not readily available. Apart from cortical sulci/gyri anatomy, FLAIR sequences are ideal for the 3D visualization of nonenhancing diffuse LGGs using the VR technique. In addition to cortical vessels (especially veins), contrast MRI sequences are perfect for the 3D visualization of contrast-enhancing high-grade gliomas.

Maximum resection and immunotherapy improve glioblastoma patient survival: a retrospective single-institution prognostic analysis

Glioblastoma (GBM) is a refractory disease with a poor prognosis and various methods, including maximum resection and immunotherapy, have been tested to improve outcomes. In this retrospective study we analyzed the prognostic factors of 277 newly diagnosed GBM patients over 11 years of consecutive cases at our institution to evaluate the effect of these methods on prognosis. Various data, including the extent of removal (EOR) and type of adjuvant therapy, were examined and prognostic relationships were analyzed. The median overall survival (OS) of the entire 277-case cohort, 200 non-biopsy cases, and 77 biopsy cases was 16.6 months, 19.7 months, and 9.7 months, respectively. Gross total removal (GTR; 100% of EOR) was achieved in 32.9% of the cases. Univariate analysis revealed younger age, right side, higher Karnofsky performance status, GTR, intraoperative magnetic resonance imaging (MRI) use for removal, proton therapy, combination immunotherapy, and discharge to home as good prognostic factors. Intraoperative MRI use and EOR were closely related. In the multivariate analysis, GTR, proton therapy, and a combination of immunotherapies, including autologous formalin-fixed tumor vaccine, were the significant prognostic factors. A multivariate analysis of 91 GTR cases showed that immunotherapy contributed to prognostic improvements. The median OS and 5-year OS % values were 36.9 months and 43.3% in GTR cases receiving immunotherapy. In conclusion, GTR, proton therapy, and immunotherapy were good prognostic factors in single-center GBM cases. Tumor vaccine therapy for GTR cases achieved a notably high median survival time and long-term survival ratio, indicating its usefulness in GTR cases.

A nomogram for individualized prediction of overall survival in patients with newly diagnosed glioblastoma: a real-world retrospective cohort study

Background

This study aimed to identify the most valuable predictors of prognosis in glioblastoma (GBM) patients and develop and validate a nomogram to estimate individualized survival probability.

Methods

We conducted a real-world retrospective cohort study of 987 GBM patients diagnosed between September 2010 and December 2018. Computer generated random numbers were used to assign patients into a training cohort (694 patients) and internal validation cohort (293 patients). A least absolute shrinkage and selection operator (LASSO)-Cox model was used to select candidate variables for the prediction model. Cox proportional hazards regression was used to estimate overall survival. Models were internally validated using the bootstrap method and generated individualized predicted survival probabilities at 6, 12, and 24 months, which were compared with actual survival.

Results

The final nomogram was developed using the Cox proportional hazards model, which was the model with best fit and calibration. Gender, age at surgery, extent of tumor resection, radiotherapy, chemotherapy, and IDH1 mutation status were used as variables. The concordance indices for 6-, 12-, 18-, and 24-month survival probabilities were 0.776, 0.677, 0.643, and 0.629 in the training set, and 0.725, 0.695, 0.652, and 0.634 in the validation set, respectively.

Conclusions

Our nomogram that assesses individualized survival probabilities (6-, 12-, and 24-month) in newly diagnosed GBM patients can assist healthcare providers in optimizing treatment and counseling patients.

Trial registration: retrospectively registered.

Current Status of Brain Tumor in the Kingdom of Saudi Arabia and Application of Nanobiotechnology for Its Treatment: A Comprehensive Review

OBJECTIVE

Brain tumors are the most challenging of all tumors and accounts for about 3% of all cancer allied deaths. The aim of the present review is to examine the brain tumor prevalence and treatment modalities available in the Kingdom of Saudi Arabia. It also provides a comprehensive analysis of the application of various nanotechnology-based products for brain cancer treatments along with their prospective future advancements.

METHODS

A literature review was performed to identify and summarize the current status of brain cancer in Saudi Arabia and the scope of nanobiotechnology in its treatment.

RESULTS

Depending upon the study population data analysis, gliomas, astrocytoma, meningioma, and metastatic cancer have a higher incidence rate in Saudi Arabia than in other countries, and are mostly treated in accordance with conventional treatment modalities for brain cancer. Due to the poor prognosis of cancer, it has an average survival rate of 2 years. Conventional therapy includes surgery, radiotherapy, chemotherapy, and a combination thereof, but these do not control the disease's recurrence. Among the various nanomaterials discussed, liposomes and polymeric nanoformulations have demonstrated encouraging outcomes for facilitated brain cancer treatment.

CONCLUSIONS

Nanomaterials possess the capacity to overcome the shortcomings of conventional therapies. Polymer-based nanomaterials have shown encouraging outcomes against brain cancer when amalgamated with other nano-based therapies. Nonetheless, nanomaterials could be devised that possess minimal toxicity towards normal cells or that specifically target tumor cells. In addition, rigorous clinical investigations are warranted to prepare them as an efficient and safe modality for brain cancer therapy.

Brain Mapping-Aided SupraTotal Resection (SpTR) of Brain Tumors: The Role of Brain Connectivity

Brain gliomas require a deep knowledge of their effects on brain connectivity. Understanding the complex relationship between tumor and functional brain is the preliminary and fundamental step for the subsequent surgery. The extent of resection (EOR) is an independent variable of surgical effectiveness and it correlates with the overall survival. Until now, great efforts have been made to achieve gross total resection (GTR) as the standard of care of brain tumor patients. However, high and low-grade gliomas have an infiltrative behavior and peritumoral white matter is often infiltrated by tumoral cells. According to these evidences, many efforts have been made to push the boundary of the resection beyond the contrast-enhanced lesion core on T1w MRI, in the so called supratotal resection (SpTR). SpTR is aimed to maximize the extent of resection and thus the overall survival. SpTR of primary brain tumors is a feasible technique and its safety is improved by intraoperative neuromonitoring and advanced neuroimaging. Only transient cognitive impairments have been reported in SpTR patients compared to GTR patients. Moreover, SpTR is related to a longer overall and progression-free survival along with preserving neuro-cognitive functions and quality of life.

Intraoperative Magnetic Resonance Imaging for Low-Grade and High-Grade Gliomas: What Is the Evidence? A Meta-Analysis

BACKGROUND

The benefit of intraoperative magnetic resonance imaging (iMRI) in gliomas remains unclear. We performed a meta-analysis of outcomes with iMRI-guided surgery in high-grade gliomas (HGGs) and low-grade gliomas (LGGs).

METHODS

Databases were searched until November 29, 2018 for randomized controlled trials (RCTs) and observational studies (OBS) comparing iMRI use with conventional neurosurgery. Pooled risk ratios (RRs) or hazard ratios were evaluated with the random-effects model. Outcomes included extent of resection (EOR), gross total resection (GTR), progression-free survival (PFS), overall survival (OS), and length of surgery (LOS), stratified by study design and glioma grade.

RESULTS

Fifteen articles (3 RCTs and 12 OBS) were included. In RCTs, GTR was higher in iMRI compared with conventional neurosurgery (RR, 1.42; 95% confidence interval [CI], 1.17-1.73; I², 7%) overall, for LGGs (1.91; 95% CI, 1.19-3.06), but not HGGs (1.24; 95% CI, 0.89-1.73), with no difference in EOR, PFS, OS, and LOS. For OBS, GTR was higher (RR, 1.65; 95% CI, 1.43-1.90; I², 4%) overall, and for LGGs (1.63; 95% CI, 1.17-2.28; I², 0%) and HGGs (1.62; 95% CI, 1.36-1.92; I², 19%). EOR was greater with iMRI (6%; 95% CI, 4%-8%; I², 44%) overall, in LGGs (5%; 95% CI, 2%-8%; I², 37%) and HGGs (7%; 95% CI, 4%-10%; I², 13%). There was no difference in PFS, OS, and LOS with iMRI.

CONCLUSIONS

IMRI use improved GTR in gliomas, including LGGs. However, no PFS and OS benefit was shown in the meta-analysis.

Intraoperative MRI versus 5-ALA in high-grade glioma resection: a network meta-analysis

OBJECTIVE

High-grade gliomas (HGGs) continue to carry poor prognoses, and patient outcomes depend heavily on the extent of resection (EOR). The utility of conventional image-guided surgery is limited by intraoperative brain shift. More recent techniques to maximize EOR, including intraoperative imaging and the use of fluorescent dyes, combat these limitations. However, the relative efficacy of these two techniques has never been systematically compared. Thus, the authors performed an exhaustive systematic review in conjunction with quantitative network meta-analyses to evaluate the comparative effectiveness of 5-aminolevulinic acid (5-ALA) and intraoperative MRI (IMRI) in optimizing EOR in HGG. They secondarily analyzed associated progression-free and overall survival and performed subgroup analyses by level of evidence.

METHODS

PubMed, Embase, Cochrane Central, and Web of Science were searched for studies evaluating conventional neuronavigation, IMRI, and 5-ALA in HGG resection. The primary study endpoint was the proportion of patients attaining gross-total resection (GTR), defined as 100% elimination of contrast-enhancing lesion on postoperative MRI. Secondary endpoints included overall and progression-free survival and subgroup analyses for level of evidence. Comparative efficacy analysis of IMRI and 5-ALA was performed using Bayesian network meta-analysis models.

RESULTS

This analysis included 11 studies. In a classic meta-analysis, both IMRI (OR 4.99, 95% CI 2.65-9.39, p < 0.001) and 5-ALA (OR 2.866, 95% CI 2.127-3.863, p < 0.001) were superior to conventional navigation in achieving GTR. Bayesian network analysis was employed to indirectly compare IMRI to 5-ALA, and no significant difference in GTR was found between the two (OR 1.9 favoring IMRI, 95% CI 0.905-3.989, p = 0.090). A handful of studies additionally suggested that the use of either IMRI (2 and 4 studies, respectively) or 5-ALA (2 and 2 studies, respectively) improves progression-free and overall survival.

CONCLUSIONS

IMRI and 5-ALA are individually superior to conventional neuronavigation for achieving GTR of HGG. Between IMRI and 5-ALA, neither method is clearly more effective. Future studies evaluating the comparative cost and surgical time associated with IMRI and 5-ALA will better inform any cost-benefit analysis.

Cerebral microcirculation in glioblastoma: A major determinant of diagnosis, resection, and drug delivery

Glioblastoma (GBM) is the most common primary brain tumor with a dismal prognosis. Current standard of treatment is safe maximal tumor resection followed by chemotherapy and radiation. Altered cerebral microcirculation and elevated blood-tumor barrier (BTB) permeability in tumor periphery due to glioma-induced vascular dysregulation allow T1 contrast-enhanced visualization of resectable tumor boundaries. Newer tracers that label the tumor and its vasculature are being increasingly used for intraoperative delineation of glioma boundaries for even more precise resection. Fluorescent 5-aminolevulinic acid (5-ALA) and indocyanine green (ICG) are examples of such intraoperative tracers. Recently, magnetic resonance imaging (MRI)-based MR thermometry is being employed for laser interstitial thermal therapy (LITT) for glioma debulking. However, aggressive, fatal recurrence always occurs. Postsurgical chemotherapy is hampered by the inability of most drugs to cross the blood-brain barrier (BBB). Understanding postsurgical changes in brain microcirculation and permeability is crucial to improve chemotherapy delivery. It is important to understand whether any microcirculatory indices can differentiate between true recurrence and radiation necrosis. LITT leads to peri-ablation BBB opening that persists for several weeks. Whether it can be a conduit for chemotherapy delivery is yet to be explored. This review will address the role of cerebral microcirculation in such emerging ideas in GBM diagnosis and therapy.

The Neurosurgeon's Armamentarium for Gliomas: An Update on Intraoperative Technologies to Improve Extent of Resection

Maximal safe resection is the standard of care in the neurosurgical treatment of high-grade gliomas. To aid surgeons in the operating room, adjuvant techniques and technologies centered around improving intraoperative visualization of tumor tissue have been developed. In this review, we will discuss the most advanced technologies, specifically fluorescence-guided surgery, intraoperative imaging, neuromonitoring modalities, and microscopic imaging techniques. The goal of these technologies is to improve detection of tumor tissue beyond what conventional microsurgery has permitted. We describe the various advances, the current state of the literature that have tested the utility of the different adjuvants in clinical practice, and future directions for improving intraoperative technologies.

Multimodal Surgical Management of Cerebral Lesions in Motor-Eloquent Areas Combining Intraoperative 3D Ultrasound with Neurophysiological Mapping

BACKGROUND

 Resection of tumors adjacent to motor pathways carries risks of both postoperative motor deficit and incomplete resection. Our aim was to assess usefulness and limitations of a multimodal strategy that combines intraoperative ultrasound (iUS) guided resection with intraoperative neurophysiology.

METHODOLOGY

 This is a prospective study of 25 patients with brain lesions adjacent to motor areas who underwent intracranial surgery with assistance of the iUS guidance system and intraoperative neurophysiological monitoring and mapping. Pathologies treated included 19 gliomas, 3 metastases, 1 anaplastic meningioma, 1 arteriovenous malformation (AVM), and 1 ependymoma. The iUS-guided lesion removal accuracy and the extent of resection were estimated and compared with a 30-day postoperative brain MRI. The results were assessed considering the extent of resection related to 6-month motor function outcome.

RESULTS

 iUS was accurate in checking the extent of resection in 17 patients, whereas in 8 cases the decline of the iUS images quality did not allow a valuable assessment. Positive mapping was obtained in 16 patients. Gross total resection was achieved in 16 patients. In five of nine cases with subtotal resection, surgery was stopped because a functional area was reached. In four patients, tumor removal was limited due to the difficulty of identifying neoplastic tissue. Motor function worsening was transient in six patients and permanent in two.

CONCLUSIONS

 The integrated use of intraoperative neuromonitoring to identify motor areas and iUS to identify tumor-tissue interface could help increase the rate of radical resection respecting the eloquent areas.

Cytoreductive surgery in the management of newly diagnosed glioblastoma in adults: a systematic review and evidence-based clinical practice guideline update

TARGET POPULATION

These recommendations apply to adults with newly diagnosed or suspected glioblastoma.

QUESTION

What is the effect of extent of surgical resection on patient outcome in the initial management of adult patients with suspected newly diagnosed glioblastoma?

RECOMMENDATION

Level II: Maximal cytoreductive surgery is recommended in adult patients with suspected newly diagnosed supratentorial glioblastoma with gross total resection defined as removal of contrast enhancing tumor. Level III: Biopsy, subtotal resection, or gross total resection is suggested depending on medical comorbidities, functional status, and location of tumor if maximal resection may cause significant neurologic deficit.

QUESTION

What is the role of cytoreductive surgery in adults with newly diagnosed bi-frontal "butterfly" glioblastoma?

RECOMMENDATION

Level III: Resection of newly diagnosed bi-frontal "butterfly" glioblastoma is suggested to improve overall survival over biopsy alone.

QUESTION

What is the goal of cytoreductive surgery in elderly adult patients with newly diagnosed glioblastoma?

RECOMMENDATION

Level III: Elderly patients (> 65 years) show survival benefit with gross total resection and it is suggested they undergo cytoreductive surgery.

QUESTION

What is the role of advanced intraoperative guidance techniques in cytoreductive surgery in adults with newly diagnosed glioblastoma?

RECOMMENDATION

Level III: The use of intraoperative guidance adjuncts such as intraoperative MRI (iMRI) or 5-aminolevulinic acid (5-ALA) are suggested to maximize extent of resection in newly diagnosed glioblastoma. There is insufficient evidence to make a suggestion on the use of fluorescein, indocyanine green, or intraoperative ultrasound.

Heterogeneity Matters: Different Regions of Glioblastoma Are Characterized by Distinctive Tumor-Supporting Pathways

Simple Summary

5-ALA Fluorescence Guided Surgery aims at extending the boundaries of glioblastoma (GBM) resection. It is based on the use of a fluorescent dye, 5-aminolevulinic acid (5-ALA). Depending on the fluorescence levels, it is possible to distinguish the core of the tumor, the infiltrating borders and the healthy tissue. Since GBM progression is supported by tumor cells and their interaction with the surrounding microenvironment, we hypothesized that 5-ALA intensity could identify microenvironments with different tumor supporting properties. Taking advantage of glioma-associated stem cells; a human in vitro model of the glioma microenvironment, we demonstrate that all regions of the tumor support the tumor growth, but through different pathways. This study highlights the importance of understanding the TME to obtain key information on GBM biology and develop new therapeutic approaches.

Abstract

The glioblastoma microenvironment plays a substantial role in glioma biology. However, few studies have investigated its spatial heterogeneity. Exploiting 5-ALA Fluorescence Guided Surgery (FGS), we were able to distinguish between the tumor core (ALA+), infiltrating area (ALA-PALE) and healthy tissue (ALA−) of the glioblastoma, based on the level of accumulated fluorescence. The aim of this study was to investigate the properties of the microenvironments associated with these regions. For this purpose, we isolated glioma-associated stem cells (GASC), resident in the glioma microenvironment, from ALA+, ALA-PALE and ALA− samples and compared them in terms of growth kinetic, phenotype and for the expression of 84 genes associated with cancer inflammation and immunity. Differentially expressed genes were correlated with transcriptomic datasets from TCGA/GTEX. Our results show that GASC derived from the three distinct regions, despite a similar phenotype, were characterized by different transcriptomic profiles. Moreover, we identified a GASC-based genetic signature predictive of overall survival and disease-free survival. This signature, highly expressed in ALA+ GASC, was also well represented in ALA PALE GASC. 5-ALA FGS allowed to underline the heterogeneity of the glioma microenvironments. Deepening knowledge of these differences can contribute to develop new adjuvant therapies targeting the crosstalk between tumor and its supporting microenvironment.

In vivo detection of murine glioblastoma through Raman and reflectance fiber-probe spectroscopies

Significance: Glioblastoma (GBM) is the most common and aggressive malignant brain tumor in adults. With a worldwide incidence rate of 2 to 3 per 100,000 people, it accounts for more than 60% of all brain cancers; currently, its 5-year survival rate is < 5 % . GBM treatment relies mainly on surgical resection. In this framework, multimodal optical spectroscopy could provide a fast and label-free tool for improving tumor detection and guiding the removal of diseased tissues. Aim: Discriminating healthy brain from GBM tissues in an animal model through the combination of Raman and reflectance spectroscopies. Approach: EGFP-GL261 cells were injected into the brains of eight laboratory mice for inducing murine GBM in these animals. A multimodal optical fiber probe combining fluorescence, Raman, and reflectance spectroscopy was used to localize in vivo healthy and tumor brain areas and to collect their spectral information. Results: Tumor areas were localized through the detection of EGFP fluorescence emission. Then, Raman and reflectance spectra were collected from healthy and tumor tissues, and later analyzed through principal component analysis and linear discriminant analysis in order to develop a classification algorithm. Raman and reflectance spectra resulted in 92% and 93% classification accuracy, respectively. Combining together these techniques allowed improving the discrimination between healthy and tumor tissues up to 97%. Conclusions: These preliminary results demonstrate the potential of multimodal fiber-probe spectroscopy for in vivo label-free detection and delineation of brain tumors, and thus represent an additional, encouraging step toward clinical translation and deployment of fiber-probe spectroscopy.

Near Infrared Fluorescent Nanoplatform for Targeted Intraoperative Resection and Chemotherapeutic Treatment of Glioblastoma

Despite significant efforts to improve glioblastoma multiforme (GBM) treatment, GBM remains one of the most lethal cancers. Effective GBM treatments require sensitive intraoperative tumor visualization and effective postoperative chemotherapeutic delivery. Unfortunately, the diffusive and infiltrating nature of GBM limits the detection of GBM tumors, and current intraoperative visualization methods limit complete tumor resection. In addition, although chemotherapy is often used to eliminate any cancerous tissue remaining after surgery, most chemotherapeutic drugs do not effectively cross the brain-blood barrier (BBB) or enter GBM tumors. As a result, GBM has limited treatment options with high recurrence rates, and methods that improve its complete visualization during surgery and treatment are needed. Herein, we report a fluorescent nanoparticle platform for the near-infrared fluorescence (NIRF)-based tumor boundary visualization and image-guided drug delivery into GBM tumors. Our nanoplatform is based on ferumoxytol (FMX), an FDA-approved magnetic resonance imaging-sensitive superparamagnetic iron oxide nanoparticle, which is conjugated with hepthamethine cyanine (HMC), a NIRF ligand that specifically targets the organic anion transporter polypeptides that are overexpressed in GBM. We have shown that HMC-FMX nanoparticles cross the BBB and selectively accumulate in the tumor using orthotopic GBM mouse models, enabling NIRF-based visualization of infiltrating tumor tissue. In addition, HMC-FMX can encapsulate chemotherapeutic drugs, such as paclitaxel or cisplatin, and deliver these agents into GBM tumors, reducing tumor size and increasing survival. Taken together, these observations indicate that HMC-FMX is a promising nanoprobe for GBM surgical visualization and drug delivery.

"Dark corridors" in 5-ALA resection of high-grade gliomas: combining fluorescence-guided surgery and contrast-enhanced ultrasonography to better explore the surgical field

BACKGROUND

Increasing the extent of resection (EOR) is considered a main goal in high grade glioma (HGG) surgery. Significant advancements have been recently made to assist surgery: namely the use of 5-aminolevulinic acid (5ALA) and the application of contrast-enhanced ultrasound (CEUS) embody two of the most recently introduced tools in the neuro-oncology field. A combined approach including the two techniques has been suggested in literature. Our primary aim is to identify in which conditions CEUS final survey has a real impact in a 5-ALA guided context and assess which preoperative tumor characteristics, with specific attention to working corridors can predict strains of the fluorescence guided procedure and hence recommend the use of the combined technique.

METHODS

Forty-nine HGG glioma surgeries were performed at our institution with the abovementioned protocol between January 2016 and June 2016. Based on preoperative MRI, we stratified glioma characteristics according to three determinants: localization (deep versus superficial), size (<3.5 versus >3.5 cm) and shape (regular versus irregular).

RESULTS

CEUS modified 5-ALA guided resection in 11 cases (22.45%): this appeared to be associated with statistically significance to deep tumor localization (P=0.04) and irregular/multi-lobulated margins (P=0.003). On the other hand, tumor size alone did not appear as a statistically significant determinant.

CONCLUSIONS

When dark corridors are presents or when overlying brain parenchyma hinders illumination, drawbacks to the 5-ALA assistance can be expected, hence CEUS final survey has a crucial role of 'refinement'. In those selected cases, an integrated 5ALA+CEUS protocol was shown as advisable in EOR improvement.

Elastic Fusion Enables Fusion of Intraoperative Magnetic Resonance Imaging Data with Preoperative Neuronavigation Data

OBJECTIVE

Intraoperative magnetic resonance imaging (iMRI) has been shown to optimize the extent of resection of parenchymal brain tumors. To facilitate the use of preoperative treatment plans after an intraoperative navigation update via iMRI, an elastic image fusion (EIF) algorithm was developed.

METHODS

Ten MRI-iMRI data pairs of patients with brain tumor were evaluated and typical anatomic landmarks were assessed. The pre- and iMRI scans were elastically fused by using a prototype EIF software (Elements Virtual iMRI [Brainlab AG]). For each landmark pair, the Euclidean distance was calculated for rigidly and elastically fused image data.

RESULTS

The Euclidean distance was 2.67 ± 2.62 mm using standard rigid image fusion and 1.8 ± 1.57 mm using our EIF algorithm (P = 0.005). For landmarks near the resected lesion, which were subject to higher anatomic distortion, the Euclidian distances were 4.38 ± 2.51 and 2.52 ± 1.9 mm (P = 0.003).

CONCLUSIONS

This feasibility study shows that EIF can compensate for surgery-related brain shift in a highly significant manner even in this small number of cases. The establishment of an easy applicable and reliable EIF tool integrated in the clinical workflow could open a large variety of new options for image-guided tumor surgery.

Innovative therapies for malignant brain tumors: the road to a tailored cure

Background:

Immune tolerance, immune escape, neoangiogenesis, phenotypic changes, and glioma stem cells are all responsible for the resistance of malignant brain tumors to current therapies and persistent recurrence. The present study provides a panoramic view of innovative therapies for malignant brain tumors, especially glioblastoma, aimed at achieving a tailored approach.

Methods:

PubMed/Medline and ClinicalTrials.gov were the main sources of an extensive literature review in which “Regenerative Medicine,” “Cell-Based Therapy,” “Chemotherapy,” “Vaccine,” “Cell Engineering,” “Immunotherapy, Active,” “Immunotherapy, Adoptive,” “Stem Cells,” “Gene Therapy,” “Target Therapy,” “Brain Cancer,” “Glioblastoma,” and “Malignant Brain Tumor” were the search terms. Only articles in English published in the last 5 years were included. A further selection was made according to the quality of the studies and level of evidence.

Results:

Cell-based and targeted therapies represent the newest frontiers of brain cancer treatment. Active and adoptive immunotherapies, stem cell therapies, and gene therapies represent a tremendous evolution in recent years due to many preclinical and clinical studies. Clinical trials have validated the effectiveness of antibody-based immunotherapies, including an in-depth study of bevacizumab, in combination with standard of care. Preclinical data highlights the role of vaccines, stem cells, and gene therapies to prevent recurrence.

Conclusion:

Monoclonal antibodies strengthen the first-line therapy for high grade gliomas. Vaccines, engineered cells, stem cells, and gene and targeted therapies are good candidates for second-line treatment of both newly diagnosed and recurrent gliomas. Further data are necessary to validate this tailored approach at the bedside. (www.actabiomedica.it)

Supramaximal resection: A systematic review of its safety, efficacy and feasibility in glioblastoma

The philosophy of 'supramaximal resection' (SMR) beyond the T1-enhanced margin holds some potential in glioblastoma surgery, but the quality of available literature has not been elucidated. A systematic review of published studies of SMR in glioblastoma surgery was performed. Articles were sought in MEDLINE, EMBASE, Scopus and Cochrane Central Register for Clinical Trials. The search items were grouped into three themes; supramaximal resection, glioblastoma and outcomes. Cases were included wherein the initial extent of resection was described as exceeding gross total resection, that is to say, beyond the area of T1-enhancement on MRI. Only newly diagnosed glioblastoma was considered. Articles containing primary patient data, including outcome data, were included; reviews, editorials, descriptive articles and systematic reviews were excluded. Subsequently, 1123 unique articles were initially retrieved. After screening article titles and abstracts for relevance to SMR in glioblastoma, seven articles remained, and were all included post-full text review. No randomized controlled trials were discovered. Almost all studies were of Level 4 quality, according to Oxford Center for Evidence-Based Medicine guidelines. The included articles yielded a total of 2019 surgically treated glioblastoma patients, 13.5% of whom underwent SMR. Preliminary results suggest SMR of glioblastoma positively impacts overall and progression free survival. However, the contemporaneous literature supporting glioblastoma SMR is of low quality, with neither anatomical nor radiographic definitional consensus for what constitutes SMR. Prospective studies of larger pooled populations with standardized technical, radiological and outcome measures in designated centers would help minimize bias and validate SMR in appropriately selected glioblastoma patients.