A Feasibility Study on a Portable Vision Device for Patients with Stroke and Brain Tumours

This prospective, single-centre cohort study aimed to evaluate the impact of a portable vision reading device, OrCam Read, on vision-related quality-of-life and independent functional status in patients with low vision due to stroke or brain tumours. Six patients with poor visual acuity or visual field defects due to a stroke or a brain tumour were enrolled at a U.S. Ophthalmology Department. Participants were trained to use OrCam Read and given a loaner device for the 1 month duration of the study. Various assessments, including daily function tests, the National Eye Institute Visual Function Questionnaire-25, and the 10-item neuro-ophthalmic supplement, were administered at the first and last visits. Patients' experience with the device was evaluated with weekly telephone and end-of-study satisfaction surveys. The main outcome measures were the patient satisfaction with OrCam and the mean assessment scores between enrolment and final visits. The intervention with OrCam significantly improved patients' ability to complete daily tasks and participants reported good satisfaction with the device. The results also show non-significant improvement with distant activities, dependency, and role difficulties. Our findings demonstrate the feasibility of studying vision-related quality-of-life using a portable vision device in this patient population and pave the way for a larger study to validate the results of this study.

Diffuse Midline H3K27-Altered Gliomas in the Spinal Cord: A Systematic Review

PURPOSE

To systematically review the clinical features, management, and outcomes of diffuse midline H3K27-altered gliomas of the spinal cord (DMG-SCs).

METHODS

PubMed, Ovid EMBASE, Scopus, and Web of Science were searched from database inception to 23 September 2023 for histologically confirmed cases of DMG-SC. Patient demographics, tumor characteristics, management information, and survival outcomes were extracted and analyzed.

RESULTS

A total of 279 patients from 39 studies were collected. Patients were mostly male (61%), with an average age of 32 years. Patients were treated with surgery, radiotherapy, and chemotherapy combined (31%) or surgery only (24%), and extent of resection was most often subtotal (38%). Temozolomide was the most common chemotherapeutic agent (81%). Radiation therapy was delivered with mean dose of 47 Gy in 23 fractions. At mean follow-up time of 21 months, 13% of patients were alive. Average median overall survival was 24 months (range of 13 to 40 months) with a median progression-free survival of 14 months. Historical WHO grades of 2 or 3 appeared to exhibit a longer average median overall survival time than that of grade 4 DMG-SCs (32 vs. 23 months, p = 0.009).

CONCLUSIONS

Outcomes for DMG-SCs are poor overall but appear to be favorable compared to intracranial DMGs. Despite the recent WHO 2021 grade 4 classification for all DMGs, given the differences in overall survival reported based on historical grading systems, future studies on DMG-SCs are needed to further define if DMG-SCs may represent a heterogeneous group of tumors with different prognoses.

Profile Characterization of Biogenic Amines in Glioblastoma Patients Undergoing Standard-of-Care Treatment

INTRODUCTION

Biogenic amines play important roles throughout cellular metabolism. This study explores a role of biogenic amines in glioblastoma pathogenesis. Here, we characterize the plasma levels of biogenic amines in glioblastoma patients undergoing standard-of-care treatment.

METHODS

We examined 138 plasma samples from 36 patients with isocitrate dehydrogenase (IDH) wild-type glioblastoma at multiple stages of treatment. Untargeted gas chromatography-time of flight mass spectrometry (GC-TOF MS) was used to measure metabolite levels. Machine learning approaches were then used to develop a predictive tool based on these datasets.

RESULTS

Surgery was associated with increased levels of 12 metabolites and decreased levels of 11 metabolites. Chemoradiation was associated with increased levels of three metabolites and decreased levels of three other metabolites. Ensemble learning models, specifically random forest (RF) and AdaBoost (AB), accurately classified treatment phases with high accuracy (RF: 0.81 ± 0.04, AB: 0.78 ± 0.05). The metabolites sorbitol and N-methylisoleucine were identified as important predictive features and confirmed via SHAP.

CONCLUSION

To our knowledge, this is the first study to describe plasma biogenic amine signatures throughout the treatment of patients with glioblastoma. A larger study is needed to confirm these results with hopes of developing a diagnostic algorithm.

In vivo characterization of the human glioblastoma infiltrative edge with label-free intraoperative fluorescence lifetime imaging

Challenges in identifying a glioblastoma's infiltrative edge during neurosurgical procedures result in rapid recurrence. A label-free fluorescence lifetime imaging (FLIm) device was used to evaluate glioblastoma's infiltrative edge in vivo in 15 patients (89 samples). FLIm data were analyzed according to tumor cell density, infiltrating tissue type (gray and white matter), and diagnosis history (new or recurrent). Infiltrations in white matter from new glioblastomas showed decreasing lifetimes and a spectral red shift with increasing tumor cell density. Areas of high versus low tumor cell density were separated through a linear discriminant analysis with a ROC-AUC=0.74. Current results support the feasibility of intraoperative FLIm for real-time in vivo brain measurements and encourage refinement to predict glioblastoma infiltrative edge, underscoring the ability of FLIm to optimize neurosurgical outcomes.

Intraoperative detection of IDH-mutant glioma using fluorescence lifetime imaging

Identifying isocitrate dehydrogenase (IDH)-mutation and glioma subtype during surgery instead of days later can aid in modifying tumor resection strategies for better survival outcomes. We report intraoperative identification of IDH-mutant glioma (N = 12 patients) with a clinically compatible fluorescence lifetime imaging (FLIm) device (excitation: 355 nm; emission spectral bands: 390/40 nm, 470/28 nm, 542/50 nm). The fluorescence-derived parameters were analyzed to study the optical contrast between IDH-mutant tumors and surrounding brain tissue. IDH-mutant oligodendrogliomas exhibited shorter lifetimes (3.3 ± 0.1 ns) than IDH-mutant astrocytomas (4.1 ± 0.1 ns). Both IDH-mutant glioma subtypes had shorter lifetimes than white matter (4.6 ± 0.4 ns) but had comparable lifetimes to cortex. Lifetimes also increased with malignancy grade within IDH-mutant oligodendrogliomas (grade 2: 2.96 ± 0.08 ns, grade 3: 3.4 ± 0.3 ns) but not within IDH-mutant astrocytomas. The current results support the feasibility of FLIm as a surgical adjuvant for identifying IDH-mutant glioma tissue.

A pilot study on metabolomic characterization of human glioblastomas and patient plasma

Purpose

To determine whether recurrent GBMs are metabolically distinct from primary GBM, and whether patient plasma can be used as a liquid biopsy to reflect this difference.

Methods

In a single center cohort study, tissue and blood samples from 15 patients with glioblastoma (9 glioblastoma tissues at diagnosis, 3 pairs of tissue, and 6 pairs of plasma specimens at diagnosis and at recurrence) were analyzed.

Results

Several metabolites had significant alternations in both tumor and plasma specimens. In the tissue, the following representative metabolites had a significant increase in peak intensity at recurrence compared to diagnosis: N-alpha-methylhistamine (p = 0.037), glycerol-3-phosphate (p = 0.029), phosphocholine (p = 0.045), and succinic acid (p = 0.025). In patient plasma, metabolites that significantly increased at recurrence included: 2,4-difluorotoluene (p = 0.031), diatrizoic acid (p = 0.032), indole-3-acetate with (p = 0.029), urea (P = 0.025), pseudouridine (p = 0.042), and maltose (p = 0.035). Metabolites that significantly decreased in plasma at recurrence were: eicosenoic acid (p = 0.017), glucose-1-phosphate (p = 0.017), FA 18:2 (linoleic acid) (p = 0.017), arginine (p = 0.036), fatty acids 20:3 (homo-gamma-linolenic acid (p = 0.036), galactosamine (p = 0.007), and FA 18:3 (linolenic acid) (P = 0.012). Principal component analysis showed that the metabolomic profiles differ between tumor tissue and patient plasma.

Conclusions

Our data suggest that metabolomic profiles of human GBM tissue and patient plasma differ at diagnosis and at recurrence. Many metabolites involved in tumorigenesis and metabolomic flexibility were identified. A larger study using targeted metabolomic assay is warranted to measure the levels of these metabolites, which will help identify the metabolomic signatures in both GBM tissue and patient plasma for risk stratification, clinical outcome prediction, and development of new adjuvant metabolomic-targeting therapy.

Application of Machine Learning to Metabolomic Profile Characterization in Glioblastoma Patients Undergoing Concurrent Chemoradiation

We here characterize changes in metabolite patterns in glioblastoma patients undergoing surgery and concurrent chemoradiation using machine learning (ML) algorithms to characterize metabolic changes during different stages of the treatment protocol. We examined 105 plasma specimens (before surgery, 2 days after surgical resection, before starting concurrent chemoradiation, and immediately after chemoradiation) from 36 patients with isocitrate dehydrogenase (IDH) wildtype glioblastoma. Untargeted GC-TOF mass spectrometry-based metabolomics was used given its superiority in identifying and quantitating small metabolites; this yielded 157 structurally identified metabolites. Using Multinomial Logistic Regression (MLR) and GradientBoostingClassifier (GB Classifier), ML models classified specimens based on metabolic changes. The classification performance of these models was evaluated using performance metrics and area under the curve (AUC) scores. Comparing post-radiation to pre-radiation showed increased levels of 15 metabolites: glycine, serine, threonine, oxoproline, 6-deoxyglucose, gluconic acid, glycerol-alpha-phosphate, ethanolamine, propyleneglycol, triethanolamine, xylitol, succinic acid, arachidonic acid, linoleic acid, and fumaric acid. After chemoradiation, a significant decrease was detected in 3-aminopiperidine 2,6-dione. An MLR classification of the treatment phases was performed with 78% accuracy and 75% precision (AUC = 0.89). The alternative GB Classifier algorithm achieved 75% accuracy and 77% precision (AUC = 0.91). Finally, we investigated specific patterns for metabolite changes in highly correlated metabolites. We identified metabolites with characteristic changing patterns between pre-surgery and post-surgery and post-radiation samples. To the best of our knowledge, this is the first study to describe blood metabolic signatures using ML algorithms during different treatment phases in patients with glioblastoma. A larger study is needed to validate the results and the potential application of this algorithm for the characterization of treatment responses.

NCCN Guidelines® Insights: Central Nervous System Cancers, Version 2.2022

The NCCN Guidelines for Central Nervous System (CNS) Cancers focus on management of the following adult CNS cancers: glioma (WHO grade 1, WHO grade 2-3 oligodendroglioma [1p19q codeleted, IDH-mutant], WHO grade 2-4 IDH-mutant astrocytoma, WHO grade 4 glioblastoma), intracranial and spinal ependymomas, medulloblastoma, limited and extensive brain metastases, leptomeningeal metastases, non-AIDS-related primary CNS lymphomas, metastatic spine tumors, meningiomas, and primary spinal cord tumors. The information contained in the algorithms and principles of management sections in the NCCN Guidelines for CNS Cancers are designed to help clinicians navigate through the complex management of patients with CNS tumors. Several important principles guide surgical management and treatment with radiotherapy and systemic therapy for adults with brain tumors. The NCCN CNS Cancers Panel meets at least annually to review comments from reviewers within their institutions, examine relevant new data from publications and abstracts, and reevaluate and update their recommendations. These NCCN Guidelines Insights summarize the panel's most recent recommendations regarding molecular profiling of gliomas.

TMET-08. METABOLOMIC CHANGES IN GLIOBLASTOMA PATIENTS UNDERGOING CONCURRENT CHEMORADIATION THERAPY

OBJECTIVE

To illustrate changes of untargeted metabolomics in patients with glioblastoma IDH wildtype undergoing concurrent radiation therapy (RT) with temozolomide (TMZ). This study implemented machine learning (ML) algorithms to predict treatment phase: pre-surgery, post-surgery, pre-radiation, and post radiation based on untargeted metabolomics data.

METHODS

Thirty-six patients with glioblastoma IDH wildtype (18 methylguanine methyltransferase [MGMT] methylated, 16 MGMT unmethylated, 2 MGMT status unknown) were enrolled into this study. Serum samples obtained from patients on the same day before surgery, 2 days after surgery, before starting their concurrent chemoradiation, and after concluding this phase of treatment. Blood samples were obtained via antecubital phlebotomy without regard for time of the day, diet, or fasting status. Untargeted metabolomics by GC-TOF mass spectrometry were obtained and compared. The proposed ML models analyzed 105 samples from 36 patients utilizing 157 structurally identified blood metabolites. Multinomial Logistic Regression (MLR) and GradientBoostingClassifier (GB Classifier) were used to classify patient samples based on detected changes in blood metabolites. The classification performance of these models was evaluated using performance metrics and AUC scores.

RESULTS

Post radiation; significant increase in the following metabolites: glycine, serine, threonine, oxoproline, 6-deoxyglucose, gluconic acid, glycerol-alpha-phosphate, ethanolamine, propyleneglycol, triethanolamine, xylitol, and fumaric acid were noted while significant decrease in 3-aminopiperidine 2,6-dione was noted post radiation. MLR produced 78% accuracy, 75% precision, and AUC = 0.89, and GB Classifier produced 75% accuracy, 77% precision and AUC = 0.91. Finally, we presented a pattern of metabolites changes per clinical stage based on pairwise correlations.

CONCLUSIONS

This study represent the first serum metabolic signature associated with RT in patients with glioblastoma. The results from the classification algorithms and pairwise correlations showed that blood metabolites have the potential to predict phase of treatment and potentially enable to evaluate response to treatment in patients with glioblastoma in a relatively small cohort.

NCOG-15. A PILOT STUDY ON RETINAL FEATURES AND COGNITIVE FUNCTION IN PATIENTS WITH LOW GRADE GLIOMAS

BACKGROUND

Retinal structure and vascular changes are used as biomarkers for preclinical Alzheimer disease. We conducted a cohort study to evaluate the feasibility of obtaining these data in patients with low-grade gliomas (LGGs) who completed chemoradiation therapy with and without self or family reported cognitive concerns.

METHODS

Optical coherence tomography (OCT) and angiography (OCTA, OptoVue, Inc.) images were obtained from 6 LGG patients and 2 healthy controls using 4.5 x 4.5 mm peripapillary and 6x6 mm macular scan patterns. We measured OCTA parameters including radial peripapillary capillary density for the peri-optic disc region, whole macular density, and foveal avascular zone (FAZ).

RESULTS

We analyzed two eyes of two control subjects, an LGG patient with normal cognition, and 5 LGG patients with cognitive impairment (mean age 45 years, range of 3 months to 10 years after chemoradiation). Both controls had normal eye exams. Average retinal nerve fiber layer thickness was thinner in patients with and without cognitive dysfunction (104 um and 106 um, respectively) than controls (123 um). A similar pattern was seen in macula thickness (283 um and 290 um vs. 325 um). The average peripapillary vessel densities were lower in patients with and without cognitive dysfunction (47.7% and 48.3%, respectively) than controls (51.9%). The whole macular vessel densities were similar in three groups (46.7 %, 48.0%, and 48.0 %). Average FAZs were larger in patients with cognitive dysfunction (0.254 mm2) than the patient with normal cognition (0.204 mm2) and controls (0.226 mm2).

CONCLUSIONS

Retinal architecture and microvascular changes measured by OCT/OCTA is feasible in LGG patients after chemoradiation. A larger prospective study is needed to investigate the role of OCT/OCTA in detecting peripapillary and perifoveal changes in brain tumor patients with treatment-associated cognitive dysfunction.

First in patient assessment of brain tumor infiltrative margins using simultaneous time-resolved measurements of 5-ALA-induced PpIX fluorescence and tissue autofluorescence

SIGNIFICANCE

5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence is currently used for image-guided glioma resection. Typically, this widefield imaging method highlights the bulk of high-grade gliomas, but it underperforms at the infiltrating edge where PpIX fluorescence is not visible to the eyes. Fluorescence lifetime imaging (FLIm) has the potential to detect PpIX fluorescence below the visible detection threshold. Moreover, simultaneous acquisition of time-resolved nicotinamide adenine (phosphate) dinucleotide [NAD(P)H] fluorescence may provide metabolic information from the tumor environment to further improve overall tumor detection.

AIM

We investigate the ability of pulse sampling, fiber-based FLIm to simultaneously image PpIX and NAD(P)H fluorescence of glioma infiltrative margins in patients.

APPROACH

A mesoscopic fiber-based point-scanning FLIm device (355 nm pulses) was used to simultaneously resolve the fluorescence decay of PpIX (629/53 nm) and NAD(P)H (470/28 nm). The FLIm device enabled data acquisition at room light and rapid (<33  ms) augmentation of FLIm parameters on the surgical field-of-view. FLIm measurements from superficial tumors and tissue areas around the resection margins were performed on three glioblastoma patients in vivo following inspection of PpIX visible fluorescence with a conventional neurosurgical microscope. Microbiopsies were collected from FLIm imaged areas for histopathological evaluation.

RESULTS

The average lifetime from PpIX and NAD(P)H fluorescence distinguished between tumor and surrounding tissue. FLIm measurements of resection margins presented a range of PpIX and NAD(P)H lifetime values (τPpIX       ∼  3 to 14 ns, τNAD(P)H  =  3 to 6 ns) associated with unaffected tissue and areas of low-density tumor infiltration.

CONCLUSIONS

Intraoperative FLIm could simultaneously detect the emission of PpIX and NAD(P)H from patients in vivo during craniotomy procedures. This approach doubles as a clinical tool to identify tumor areas while performing tissue resection and as a research tool to study tumor microenvironmental changes in vivo. Intraoperative FLIm of 5-ALA-induced PpIX and tissue autofluorescence makes a promising surgical adjunct to guide tumor resection surgery.

FLGS-04. Fluorescence lifetime imaging (FLIm) is a dye-free, high sensitivity approach for fluorescence guided surgery in high-grade and low-grade gliomas

INTRODUCTION

Fluorescence-guided surgery can improve tumor identification and extent of surgical resection. 5-ALA is the standard for GBM, but is limited by lack of quantitative fluorescence, a need to work in the dark, and a lack of sensitivity for low grade tumors. We have developed a novel instrument for dye-free tissue autofluorescence lifetime imaging (FLIm) to identify glioma tissue during resection. This approach utilizes time-resolved autofluorescence measurements in narrow-band channels to assess markers of tissue metabolism. Compared to intensity-based imaging of exogenous fluorophores, FLIm has greater sensitivity without dependence on background lighting. The advantages of FLIm include quantitative tissue analysis, the ability to work under full light conditions, sensitivity for high and low grade gliomas, and the potential ability to identify IDH mutational status. In this study, we validated the use of FLIm for identification of glioma tissue at tumor resection margins.

METHODS

FLIm was used to image tissue margins during glioma resections and compared to microbiopsies from imaged regions to correlate fluorescence with histopathology.

RESULTS

FLIm was applied intraoperatively to 11 GBM and 5 LGG patients (7 imaged biopsies per patient). In GBM, tumor infiltration of cortex was associated with significantly decreased fluorescence lifetime (FL) in channels 2 (470/28nm;p&lt;0.05) and 3 (542/50nm;p&lt;0.002). In subcortical margins, FL was inversely proportional to the density of tumor in channels 2,3 (p&lt;0.05). When IDH wild-type GBMs were compared to IDH1-mutant tumors, FL was noted to be significantly longer in channel 1 (390/40nm;p&lt;0.05), and trended towards longer FL in channel 2, shorter FL in channel 3. In LGG, FL was significantly correlated with tumor density in channel 2 (p&lt;0.01).

CONCLUSIONS

FLIm is a dye-free, quantitative alternative to 5-ALA for fluorescence guided glioma resections with sensitivity to high and low-grade tumors, and the ability to predict IDH mutations in GBM. Further validation studies are on-going.

Correlation between social media utilization by academic neurosurgery departments and higher online patient ratings

OBJECTIVE

Patients increasingly utilize online physician review websites (PRWs) and social media to inform healthcare-related decisions. This provides neurosurgeons with opportunities for increased patient engagement. And despite the growing use of social media among neurosurgeons, the relationship between social media utilization and online reviews remains unknown. The goal of this study was to characterize the relationship between social media utilization and PRW ratings across academic neurosurgery departments.

METHODS

Social media accounts (Twitter, Facebook, YouTube, Instagram) of academic neurosurgery departments were identified. Online reviews for individual faculty were obtained from Healthgrades, Vitals, WebMD, and Google. Reviews were aggregated to identify the total number of reviews per department, to generate a composite departmental rating, and to calculate a summed departmental score. US News & World Report (USNWR) and Doximity rankings were recorded for each department. Social media utilization by individual neurosurgeons and associated ratings were investigated within the departments with the highest social media utilization.

RESULTS

Seventy-eight percent of academic neurosurgery departments utilized social media. The most prevalent platform was YouTube (49.1%), followed by Twitter (46.5%), Facebook (38.6%), and Instagram (16.7%). Higher patient ratings on PRWs were associated with the utilization of YouTube (p = 0.048) or Twitter (p = 0.02). The number of social media platforms utilized demonstrated a significant, positive correlation with patient ratings (p = 0.006) and summed patient ratings (p = 0.048). Although USNWR (p = 0.02) and Doximity (p = 0.0008) rankings correlated with patient ratings, only the number of social media platforms utilized remained a significant predictor of patient ratings on multivariate analysis (p = 0.0001). Thirty-one percent of academic neurosurgeons from departments with high social media utilization were active on social media. The most prevalent social media platform among individual neurosurgeons was Twitter (27.4%), followed by Instagram (8.4%), Facebook (4.9%), and YouTube (2.2%). Higher summed patient scores were associated with individual neurosurgeon utilization of YouTube (p = 0.04), Facebook (p < 0.0001), and Instagram (p = 0.01). Increased social media utilization among neurosurgeons was correlated with a greater number of patient reviews (p = 0.006) and higher summed patient scores (p = 0.003). On multivariate analysis, only Facebook use remained a significant predictor of the number of patient reviews received (p = 0.002) and summed patient satisfaction scores (p < 0.001).

CONCLUSIONS

An increased social media presence is associated with higher ratings on PRWs. As neurosurgeons continue to expand their online presence, they should be aware of the possible impact of social media on online patient reviews.

A first-in-human phase 0 clinical study of RNA interference-based spherical nucleic acids in patients with recurrent glioblastoma

Glioblastoma (GBM) is one of the most difficult cancers to effectively treat, in part because of the lack of precision therapies and limited therapeutic access to intracranial tumor sites due to the presence of the blood-brain and blood-tumor barriers. We have developed a precision medicine approach for GBM treatment that involves the use of brain-penetrant RNA interference-based spherical nucleic acids (SNAs), which consist of gold nanoparticle cores covalently conjugated with radially oriented and densely packed small interfering RNA (siRNA) oligonucleotides. On the basis of previous preclinical evaluation, we conducted toxicology and toxicokinetic studies in nonhuman primates and a single-arm, open-label phase 0 first-in-human trial (NCT03020017) to determine safety, pharmacokinetics, intratumoral accumulation and gene-suppressive activity of systemically administered SNAs carrying siRNA specific for the GBM oncogene Bcl2Like12 (Bcl2L12). Patients with recurrent GBM were treated with intravenous administration of siBcl2L12-SNAs (drug moniker: NU-0129), at a dose corresponding to 1/50th of the no-observed-adverse-event level, followed by tumor resection. Safety assessment revealed no grade 4 or 5 treatment-related toxicities. Inductively coupled plasma mass spectrometry, x-ray fluorescence microscopy, and silver staining of resected GBM tissue demonstrated that intravenously administered SNAs reached patient tumors, with gold enrichment observed in the tumor-associated endothelium, macrophages, and tumor cells. NU-0129 uptake into glioma cells correlated with a reduction in tumor-associated Bcl2L12 protein expression, as indicated by comparison of matched primary tumor and NU-0129-treated recurrent tumor. Our results establish SNA nanoconjugates as a potential brain-penetrant precision medicine approach for the systemic treatment of GBM.

Unfractionated Heparin TID Dosing Regimen Is Associated With a Lower Rate of Pulmonary Embolism When Compared With BID Dosing in Patients Undergoing Craniotomy

BACKGROUND

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), and intracranial hemorrhage (ICH) may complicate the post-operative course of patients undergoing craniotomy. While prophylaxis with unfractionated heparin (UFH) has been shown to reduce VTE rates, twice-daily (BID) and three-times-daily (TID) UFH dosing regimens have not been compared in neurosurgical procedures. The objective of this study was to explore the association between UFH dosing regimen and rates of VTE and ICH in craniotomy patients.

METHODS

A retrospective chart review was conducted for 159 patients at Northwestern University receiving 5000 units/0.5 mL UFH injections either BID (n = 132) or TID (n = 27). General linear regression models were run to predict rates of DVT, PE, and reoperation due to bleeding from UFH dosing regimen while controlling for age at surgery, sex, VTE history, craniotomy for tumor resection, surgery duration, length of stay, reoperation, infections, and IDH/MGMT mutations.

RESULTS

Receiving UFH TID was significantly associated with a lower rate of PE when compared with receiving UFH BID (β = -0.121, P = 0.044; TID rate = 0%, BID rate = 10.6%). UFH TID also showed a trend toward lower rates of DVT (β = -0.0893, P = 0.295; TID rate = 18.5%, BID rate = 21.2%) when compared with UFH BID. UFH TID showed no significant difference in rate of reoperation for bleeding when compared to UFH BID (β = -0.00623, P = 0.725; TID rate = 0%, BID rate = 0.8%).

CONCLUSIONS

UFH TID dosing is associated with lower rates of PE when compared with BID dosing in patients undergoing craniotomy.

Lumboperitoneal shunts for the treatment of idiopathic normal pressure hydrocephalus

The standard of care for idiopathic normal pressure hydrocephalus (iNPH) is placement of a ventriculoperitoneal (VP) shunt. However, VP shunts require intracranial intervention and are associated with notable postoperative complications, with some groups reporting complication rates for VP shunts ranging from 17 to 33%, along with failure rates up to 17.7%. Lumboperitoneal (LP) shunts are an alternative for cerebrospinal fluid diversion that do not require intracranial surgery, thus providing utility in patients where intracranial surgery is not possible or preferred. Here we retrospectively reviewed our 25 patients with LP horizontal-vertical (LP-HV) shunts placement for initial treatment for iNPH from 2014 to 2019. All patients had preoperative gait dysfunction, 16 (64%) had urinary incontinence, and 21 (84%) exhibited cognitive insufficiency. Two weeks post-shunt placement, 23/25 (92%) patients demonstrated improvement in gait, 11/16 (68%) had improvement in incontinence, and 14/21 (66%) had improvement cognitive insufficiency. At six months or greater follow up 13/20 (65%) had improvement in gait, 7/15 (47%) showed improvement in incontinence, and 11/15 (73%) demonstrated improvement in cognitive function. Six patients (24%) required at least one revision of the LP shunt. Shunt malfunctions resulted from CSF leak in one patient, shunt catheter migration in two patients, peritoneal catheter pain in one patient, and clinical symptoms for overdrainage in two patients. Thus, we demonstrate that LP-HV shunt placement is safe and efficacious alternative to VP shunting for iNPH, resulting in notable symptomatic improvement and low risk of overdrainage, and may be considered for patients where cranial approaches should be avoided.

The Practical Application of Emerging Technologies Influencing the Diagnosis and Care of Patients With Primary Brain Tumors

Over the past decade, a variety of new and innovative technologies has led to important advances in the diagnosis and management of patients with primary malignant brain tumors. New approaches to surgical navigation and tumor localization, advanced imaging to define tumor biology and treatment response, and the widespread adoption of a molecularly defined integrated diagnostic paradigm that complements traditional histopathologic diagnosis continue to impact the day-to-day care of these patients. In the neuro-oncology clinic, discussions with patients about the role of tumor treating fields (TTFields) and the incorporation of next-generation sequencing (NGS) data into therapeutic decision-making are now a standard practice. This article summarizes newer applications of technology influencing the pathologic, neuroimaging, neurosurgical, and medical management of patients with malignant primary brain tumors.

Brain Metastasis Recurrence Versus Radiation Necrosis: Evaluation and Treatment

Radiation necrosis (RN) occurs in 5% to 25% of patients with brain metastases treated with stereotactic radiosurgery. RN must be distinguished from recurrent tumor to determine appropriate treatment. Stereotactic biopsy remains the gold standard for identifying RN. Initial treatment of RN often involves management of edema using corticosteroids, antiangiogenic therapies, and hyperbaric oxygen therapy. For refractory symptoms, surgical resection can be considered. Minimally invasive stereotactic laser ablation has the benefit of providing tissue diagnosis and treating RN or recurrent tumor with similar efficacy. Laser ablation should be considered for lesions in need of intervention where the diagnosis requires tissue confirmation.

Intraventricular adult Taenia solium causing hydrocephalus: A case report

Background:

Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system worldwide and is caused by the larval form of the tapeworm Taenia solium. In general, T. solium larval form may be located in the neuraxis, resulting in pathology. Here, we report a rare case of female with a history of adult onset seizures presenting with adult form T. solium in the fourth ventricle, causing hydrocephalus.

Case Description:

A 36-year-old female patient with a known history of adult onset seizures presented with a 1-year history of progressively worsening bilateral headaches with vertigo and intermittent nausea. A computerized tomography scan revealed ventriculomegaly and transependymal flow, with an obstruction at the level of the fourth ventricle. Outpatient magnetic resonance imaging demonstrated obstructive hydrocephalus secondary to a lobulated cystic mass within the fourth ventricle, demonstrating a gross appearance consistent with racemose NCC. The patient underwent endoscopic third ventriculostomy, and gross examination of the resected cyst revealed a mature T. solium larvae encased in a cystic membrane. Given that our patient was born and raised in Mexico but had not returned since the age of 8, NCC was an unexpected finding.

Conclusion:

The present case highlights the importance of maintaining high suspicion for NCC in all patients presenting with seizures or hydrocephalus of unknown cause. Even in patients with a very remote history of residence in an endemic country, NCC can be an overlooked, underlying cause of both chronic neurologic symptoms, as well as acute, life-threatening neurologic emergencies.

Tumor-induced peripheral immunosuppression promotes brain metastasis in patients with non-small cell lung cancer

INTRODUCTION

Brain metastases are a significant source of morbidity and mortality for patients with lung cancer. Lung cancer can induce local and systemic immunosuppression, promoting tumor growth and dissemination. One mechanism of immunosuppression is tumor-induced expansion of programmed death-ligand 1 (PD-L1) expressing myeloid cells. Here, we investigate peripheral blood immune phenotype in NSCLC patients with or without brain metastasis.

METHODS

Peripheral blood was collected from patients with lung metastatic brain tumors and pre-metastatic lung cancer. Immunosuppressive monocytes, myeloid-derived suppressor cells (MDSCs), and regulatory T cells (Tregs) were quantified through flow cytometry. T cell reactivity was analyzed via ELISpot. Brain metastasis conditioned media was collected from tumor-derived cell cultures and analyzed for cytokines by ELISA. Naïve monocytes were stimulated with brain metastasis conditioned media to evaluate PD-L1 stimulation.

RESULTS

Patients with brain metastatic lung carcinoma demonstrated increased peripheral monocyte PD-L1, MDSC abundance, and Treg percentage compared to early stage pre-metastatic patients and healthy controls. Patients with elevated peripheral monocyte PD-L1 had less reactive T cells and worse survival. Brain metastasis conditioned media stimulation increased monocyte PD-L1, and conditioned media IL-6 levels correlated with PD-L1 induction. Treatment with anti-IL-6 or anti-IL-6 receptor antibodies reduced PD-L1 expression. In summary, patients with lung cancer and brain metastases exhibit multiple markers of peripheral immunosuppression.

CONCLUSIONS

The frequency of PD-L1+ myeloid cells correlated with the presence of brain metastases. Tumor-derived IL-6 was capable of inducing PD-L1+ myeloid cells in vitro, suggesting that monitoring of immunosuppressive factors in peripheral blood may identify new targets for therapeutic intervention in selected patients.

Glioblastoma-Derived IL6 Induces Immunosuppressive Peripheral Myeloid Cell PD-L1 and Promotes Tumor Growth

PURPOSE

Upregulation of programmed death-ligand 1 (PD-L1) on circulating and tumor-infiltrating myeloid cells is a critical component of GBM-mediated immunosuppression that has been associated with diminished response to vaccine immunotherapy and poor survival. Although GBM-derived soluble factors have been implicated in myeloid PD-L1 expression, the identity of such factors has remained unknown. This study aimed to identify factors responsible for myeloid PD-L1 upregulation as potential targets for immune modulation.

EXPERIMENTAL DESIGN

Conditioned media from patient-derived GBM explant cell cultures was assessed for cytokine expression and utilized to stimulate naïve myeloid cells. Myeloid PD-L1 induction was quantified by flow cytometry. Candidate cytokines correlated with PD-L1 induction were evaluated in tumor sections and plasma for relationships with survival and myeloid PD-L1 expression. The role of identified cytokines on immunosuppression and survival was investigated in vivo utilizing immunocompetent C57BL/6 mice bearing syngeneic GL261 and CT-2A tumors.

RESULTS

GBM-derived IL6 was identified as a cytokine that is necessary and sufficient for myeloid PD-L1 induction in GBM through a STAT3-dependent mechanism. Inhibition of IL6 signaling in orthotopic murine glioma models was associated with reduced myeloid PD-L1 expression, diminished tumor growth, and increased survival. The therapeutic benefit of anti-IL6 therapy proved to be CD8+ T-cell dependent, and the antitumor activity was additive with that provided by programmed death-1 (PD-1)-targeted immunotherapy.

CONCLUSIONS

Our findings suggest that disruption of IL6 signaling in GBM reduces local and systemic myeloid-driven immunosuppression and enhances immune-mediated antitumor responses against GBM.

Systemic and local immunosuppression in patients with high-grade meningiomas

AIM

Despite current treatments, high-grade meningiomas continue to have a poor prognosis. Immunotherapy targeting immune checkpoints, such as PD-L1, has demonstrated significant success in controlling numerous malignancies. In this study, we investigate the extent of systemic and local immunosuppression in meningiomas to assess the potential benefit of immune checkpoint inhibitors for the treatment of high-grade meningiomas.

METHODS

Peripheral blood was collected from patients undergoing resection of meningiomas (WHO grade I, n = 18; grade II, n = 25; grade III, n = 10). Immunosuppressive myeloid cells (CD45+CD11b+PD-L1+), myeloid-derived suppressor cells (MDSCs) (CD11b+CD33+HLA-DRlow), and regulatory T cells (Tregs) (CD3+CD4+CD25+FoxP3+) were quantified through flow cytometry. Tissue sections from the same patients were assessed for PD-L1 expression and T cell infiltration via immunohistochemistry.

RESULTS

Patients with grade III meningiomas demonstrated increased peripheral monocyte PD-L1 compared to patients with grade I/II meningiomas and healthy controls. Peripheral MDSC abundance was increased in grades II and III meningioma patients. PD-L1 staining of meningioma tissue demonstrated increased positivity in grade III meningiomas. Intratumoral PD-L1 was not associated with progression-free survival. High-grade meningiomas had increased T-cell infiltration. However, a significant proportion of these T cells were exhausted PD1+ T cells and immunosuppressive Tregs.

CONCLUSIONS

Patients with meningiomas exhibit signs of peripheral immunosuppression, including increased PD-L1 on myeloid cells and elevated MDSC abundance proportional to tumor grade. Additionally, the tumors express substantial PD-L1 proportional to tumor grade. These results suggest a role for immune checkpoint inhibitors targeting the PD-L1/PD-1 pathway in combination with standard therapies for the treatment of high-grade meningiomas.

Lymphopenia predicts response to stereotactic radiosurgery in lung cancer patients with brain metastases

BACKGROUND

Stereotactic radiosurgery (SRS) can enhance immune activation and improve disease control through stimulation of anti-tumor immunity. However, patients with cancer receiving chemotherapy are often immunosuppressed, which may impact the efficacy of SRS. Here we investigate the relationship between systemic lymphopenia and response to SRS in patients with brain-metastatic lung cancer.

METHODS

We reviewed 125 patients with lung cancer brain metastases treated with SRS between January 2014 and May 2017. Complete blood counts from the time of SRS were reviewed, and lymphopenia was defined as absolute lymphocyte count < 1×10⁹ cells/L. Kaplan-Meier survival analysis and cox proportional-hazards models were used to evaluate risks of progression and death.

RESULTS

The median age was 65 years (range 43-86), with 54% female patients. Lymphopenia was present in 60 patients. In univariate analysis, lymphopenic patients had significantly shorter PFS (HR = 2.995, p < 0.0001) and OS (HR = 3.928, p < 0.0001). When accounting for age, gender, smoking history, ECOG score, surgery, and tumor histology in a multivariate model, lymphopenia remained significantly predictive of worse PFS (HR = 1.912, p = 0.002) and OS (HR = 2.257, p < 0.001). Patients who received immunotherapy within 3 months of SRS demonstrated significantly shorter PFS (HR = 3.578, p = 0.006) and OS (HR = 6.409, p = 0.001) if lymphopenic.

CONCLUSIONS

Brain-metastatic lung cancer patients with lymphopenia treated with SRS had significantly worse PFS and OS. The effect of lymphopenia was even more pronounced in patients receiving immunotherapy. These data demonstrate the significant impact of deficient immunity on disease control and survival. Lymphopenic patients may benefit from interventions to improve immune function prior to SRS for brain metastases.

Long-term glioblastoma survival following recovery from cytomegalovirus colitis: A case report

Survival outcomes for patients with glioblastoma (GBM) are universally poor with only a small percentage of patients surviving five years beyond initial diagnosis. Activation of the immune system against tumor cells is the basis of immunotherapy and aims to facilitate long-term immune surveillance and tumor suppression. Cytomegalovirus (CMV) has emerged as an immunologic target in GBM given that tumor cells have been shown to express the CMV-associated proteins IE1 and pp65. Moreover, vaccine therapy targeting CMV antigens has promoted improved survival outcomes with long-term survivors. In this report, we present the case of a 69 year-old woman with GBM who survived seven years post-diagnosis. Following tumor resection, the patient underwent concomitant radiation and temozolomide therapy that was complicated by CMV colitis and abdominal abscesses. Despite not receiving adjuvant temozolomide, the patient demonstrated a five year progression-free survival before requiring re-resection for radiation necrosis. Following re-resection, the patient survived for two additional years. As the patient's tumor stained positive for CMV antigens IE1 and pp65, it is hypothesized that she developed an immune response against CMV during recovery that contributed to anti-tumor surveillance and prolonged survival. Overall, this case supports further investigation into the role of CMV and immunotherapy in GBM.

Stereotactic radiosurgery for the treatment of brain metastasis from gastrointestinal primary cancers

PURPOSE

We aimed to determine the efficacy of gamma knife stereotactic radiosurgery (SRS) to control brain metastases (BM) from GI primaries and report on the patient outcomes.

MATERIALS/METHODS

We retrospectively evaluated patients who had undergone SRS at our institution for the treatment BM from GI primaries from 2000 to 2016. Actuarial rates for overall survival (OS) and local control (LC) were calculated. Survival rates were computed via the Kaplan-Meier method from the day of SRS. Multivariate analysis (MVA) using proportional hazards regression was done to determine prognostic factors for OS and LC.

RESULTS

53 patients with a total of 148 BM were treated with SRS. The median age at SRS was 60 years and the median treatment dose was 18 Gy. SRS was given as an adjuvant treatment to 30.4% of lesions. Twelve patients underwent second course of SRS for new/recurrent lesions at a median of 8 months from the first SRS (range 2-25.5). Twelve patients (22.6%) received salvage whole brain radiation. The median follow up time from the diagnosis of BM was 6 months. Local control rate at 6 months was 74.33% and 57.21% at 12 months. The OS at 1 year was 34% and 8% at 3 years. On MVA, higher GK dose was associated with better LC, and and >10 BM trended towards higher risk of local recurrence (LR). None of the tested factors proved to be significant for OS on MVA. No radiographic radionecrosis was observed on follow up MRI.

CONCLUSIONS

SRS is a safe treatment modality for the management of CNS metastases from GI primary. Consideration for dose-escalated approaches may improve LC rates.

Stereotactic Radiosurgery for Neurosurgical Patients: A Historical Review and Current Perspectives

Today, stereotactic radiosurgery is an effective therapy for a variety of intracranial pathology that were treated solely with open neurosurgery in the past. The technique was developed from the combination of therapeutic radiation and stereotactic devices for the precise localization of intracranial targets. Although stereotactic radiosurgery was originally performed as a partnership between neurosurgeons and radiation oncologists, this partnership has weakened in recent years, with some procedures being performed without neurosurgeons. At the same time, neurosurgeons across the United States and Canada have found their stereotactic radiosurgery training during residency inadequate. Although neurosurgeons, residency directors, and department chairs agree that stereotactic radiosurgery education and exposure during neurosurgery training could be improved, a limited number of resources exist for this kind of education. This review describes the history of stereotactic radiosurgery, assesses the state of its use and education today, and provides recommendations for the improvement of neurosurgical education in stereotactic radiosurgery for the future.

Postoperative stereotactic radiosurgery for patients with resected brain metastases: a volumetric analysis

PURPOSE

Postoperative stereotactic radiosurgery (SRS) is increasingly utilized following resection of brain metastases (BM); however, there are no volumetric data guiding dose selection. We performed a volumetric analysis to guide cavity SRS dosing for resected BM.

METHODS

83 consecutive patients with gross total resection who underwent postoperative SRS to 90 cavities were identified. The 12 Gy isodose lines (V12_total) along with the volume of brain parenchyma receiving 12 Gy excluding cavity fluid, ventricular fluid, and calvarium (V12_parenchyma) were contoured. Local recurrence (LR) and radionecrosis (RN) were calculated using cumulative incidence rates. Multivariate analysis (MVA) and cutpoint analysis were conducted.

RESULTS

Median follow-up was 12.3 months; median dose was 16 Gy. 1- and 2-year cumulative incidence rates of LR were 7.9% and 11.0%. Radiation dose [hazard ratio (HR) 2.04, p = 0.002] was significantly associated with time to LR on MVA. 1- and 2-year cumulative incidence rates of RN were 2.6% and 5.5% respectively. MVA demonstrated increased risk of RN with a larger V12_parenchyma (HR 1.46, p = 0.0496). Cavities ≤ 10 cc showed a low 2-year RN risk (4.3%), but had a modest LR risk (13.9%). A radiation dose ≥ 18 Gy significantly improved LC (HR 4.79, p = 0.01).

CONCLUSIONS

V12_parenchyma should be examined in postoperative SRS to assess RN risk. Cavities > 10 cc treated with 16 Gy achieved excellent LC and minimal RN at 2 years. Cavities ≤ 10 cc may be better treated with a dose ≥ 18 Gy to significantly improve LC given the low RN rate observed with 16 Gy.

The immune checkpoint protein PD-L1 induces and maintains regulatory T cells in glioblastoma

Glioblastoma (GBM) promotes immunosuppression through upregulation of PD-L1 and regulatory T cell (Treg) expansion, but the association of these suppressive factors has not been well elucidated. Here, we investigate a role of PD-L1 in expanding Tregs and the value of targeting the PD-1 receptor to inhibit Treg expansion. Quantitative RNA sequencing data from The Cancer Genome Atlas were evaluated for an association between CD274 and FOXP3 transcript expressions and impact of FOXP3 on clinical outcomes. Peripheral leukocytes from patients with newly diagnosed GBM were profiled for PD-L1⁺ myeloid expressions and Treg abundance. Healthy lymphocytes were assessed for impact of recombinant PD-L1 on expansion of the inducible Treg (iTreg) population. iTreg function was evaluated by the capacity to suppress effector T cell proliferation. Specificity of responses were confirmed by pharmacologic inhibition of the PD-1 receptor. Increased PD-L1 mRNA expression in GBM corresponded to increased FOXP3 mRNA (p = 0.028). FOXP3 elevation had a negative impact on overall survival (HR = 2.0; p < 0.001). Peripheral PD-L1 positivity was associated with an increased Treg fraction (p = 0.008). Lymphocyte activation with PD-L1 co-stimulation resulted in greater iTreg expansion compared to activation alone (18.3% vs. 6.5%; p < 0.001) and improved preservation of the Treg phenotype. Suppressive capacity on naïve T cell proliferation was sustained. Nivolumab inhibited PD-L1-induced Treg expansion (p < 0.001). These results suggest that PD-L1 may expand and maintain immunosuppressive Tregs, which are associated with decreased survival in glioma patients. Blockade of the PD-L1/PD-1 axis may reduce Treg expansion and further improve T cell function beyond the direct impact on effector cells.

Planned Subtotal Resection of Vestibular Schwannoma Differs from the Ideal Radiosurgical Target Defined by Adaptive Hybrid Surgery

OBJECTIVE

To retrospectively compare ideal radiosurgical target volumes defined by a manual method (surgeon) to those determined by Adaptive Hybrid Surgery (AHS) operative planning software in 7 patients with vestibular schwannoma (VS).

METHODS

Four attending surgeons (3 neurosurgeons and 1 ear, nose, and throat surgeon) manually contoured planned residual tumors volumes for 7 consecutive patients with VS. Next, the AHS software determined the ideal radiosurgical target volumes based on a specified radiotherapy plan. Our primary measure was the difference between the average planned residual tumor volumes and the ideal radiosurgical target volumes defined by AHS (dRV_AHS-planned).

RESULTS

We included 7 consecutive patients with VS in this study. The planned residual tumor volumes were smaller than the ideal radiosurgical target volumes defined by AHS (1.6 vs. 4.5 cm³, P = 0.004). On average, the actual post-operative residual tumor volumes were smaller than the ideal radiosurgical target volumes defined by AHS (2.2 cm³ vs. 4.5 cm³; P = 0.02). The average difference between the ideal radiosurgical target volume defined by AHS and the planned residual tumor volume (dRV_AHS-planned) was 2.9 ± 1.7 cm³, and we observed a trend toward larger dRV_AHS-planned in patients who lost serviceable facial nerve function compared with patients who maintained serviceable facial nerve function (4.7 cm³ vs. 1.9 cm³; P = 0.06).

CONCLUSIONS

Planned subtotal resection of VS diverges from the ideal radiosurgical target defined by AHS, but whether that influences clinical outcomes is unclear.

Sellar plasmacytomas masquerading as pituitary adenomas: A systematic review

Given the rarity of intracranial plasmacytomas, these lesions are frequently misdiagnosed as pituitary adenomas. We report on the distinguishing characteristics of sellar plasmacytomas from cases in the literature and our experience. A literature search was conducted to collect all documented cases of a plasmacytoma originating in the sellar region. Patient characteristics, medical history, presentation, tumor characteristics, and survival data were collected. An additional case from our institution not previously reported was included. Thirty-one patients with sellar plasmacytomas were studied. Presenting symptoms were most commonly headache (68%), diplopia (65%) and visual field disturbances (10%). Fifteen patients (48%) were initially suspected of having a pituitary adenoma. Pathologic diagnosis of plasmacytoma preceded a finding of multiple myeloma in 14 cases (45%). Thirty patients (90%) had surgical intervention. Adjuvant therapy consisted of radiotherapy for twenty-five patients (81%) and chemotherapy for sixteen (52%). Tumor recurrence was reported for 7 cases (23%). Nine deaths were reported (23%). We demonstrate that cranial nerve involvement is far more common in sellar plasmacytomas than conventional pituitary adenomas. Given the successful management of these tumors with radiotherapy, such deficits, particularly in patients with known multiple myeloma, should impact the diagnostic workup and treatment considerations.

Gross total resection and adjuvant radiotherapy most significant predictors of improved survival in patients with atypical meningioma

BACKGROUND

Atypical and malignant meningiomas are far less common than benign meningiomas. As aggressive lesions, they are prone to local recurrence and may lead to decreased survival. Although malignant meningiomas typically are treated with maximal surgical resection and adjuvant radiotherapy (RT), to the authors' knowledge the optimal treatment for atypical lesions remains to be defined. There are limited prospective data in this setting.

METHODS

The National Cancer Data Base was queried to investigate cases of histologically confirmed meningiomas diagnosed from 2004 to 2014. This included 7811 patients with atypical meningiomas (World Health Organization grade 2) and 1936 patients with malignant meningiomas (World Health Organization grade 3); during the same period, a total of 60,345 patients were diagnosed with benign meningiomas (World Health Organization grade 1). Data collected included patient and tumor characteristics, extent of surgical resection, and use of RT. Survival analysis was performed using Kaplan-Meier estimates with the log-rank test of significance and Cox univariate and multivariate regression. Logistic regression was used to determine factors associated with use of RT.

RESULTS

The 5-year overall survival rate was 85.5% in patients with benign meningiomas, 75.9% in patients with atypical meningiomas, and 55.4% in patients with malignant meningiomas (P<.0001). In patients with atypical meningiomas, gross (macroscopic) total resection (GTR) and adjuvant RT were found to be associated with significantly improved survival, independently and especially in unison (GTR plus RT: hazard ratio, 0.47; P = .002). On multivariate analysis, the combination of GTR plus RT was found to be the most important factor for improved survival. However, GTR was associated with significantly lower rates of RT use.

CONCLUSIONS

GTR and adjuvant RT appear to be highly associated with improved survival, independent of other factors, in patients with atypical meningiomas. Cancer 2018;124:734-42. © 2017 American Cancer Society.

Autologous Heat Shock Protein Peptide Vaccination for Newly Diagnosed Glioblastoma: Impact of Peripheral PD-L1 Expression on Response to Therapy

Purpose: Standard therapy for newly diagnosed glioblastoma (GBM) is surgical resection, followed by concurrent radiotherapy and temozolomide chemotherapy. In this phase II clinical trial, the addition of an autologous heat-shock protein vaccine to standard therapy was evaluated. Tumor-induced immunosuppression, mediated by expression of PD-L1 on tumor and circulating immune cells, may impact the efficacy of vaccination. Expression of PD-L1 on peripheral myeloid cells was evaluated for the first time as a predictor of survival.Experimental Design: In this single arm, phase II study, adult patients with GBM underwent surgical resection followed by standard radiation and chemotherapy. Autologous vaccine (Prophage) was generated from resected tumors and delivered in weekly vaccinations after completion of radiotherapy. The primary endpoint was overall survival.Results: Forty-six patients received the vaccine with a median overall survival of 23.8 months [95% confidence interval (CI), 19.8-30.2]. Median overall survival for patients with high PD-L1 expression on myeloid cells was 18.0 months (95% CI, 10.0-23.3) as compared with 44.7 months (95% CI, incalculable) for patients with low PD-L1 expression (hazard ratio 3.3; 95% CI, 1.4-8.6; P = 0.007). A multivariate proportional hazards model revealed MGMT methylation, Karnofsky performance status, and PD-L1 expression as the primary independent predictors of survival.Conclusions: Vaccination with autologous tumor-derived heat shock proteins may improve survival for GBM patients when combined with standard therapy and warrants further study. Systemic immunosuppression mediated by peripheral myeloid expression of PD-L1 is a recently identified factor that may significantly impact vaccine efficacy. Clin Cancer Res; 23(14); 3575-84. ©2017 AACR.

Gamma Knife Stereotactic Radiosurgery for Grade 2 Meningiomas

Purpose  This study aims to report long-term clinical outcomes after Gamma Knife radiosurgery (GKRS) for intracranial grade 2 meningiomas. Methods  In this Institutional Review Board approved study, we reviewed records of all patients with grade 2 meningiomas treated with GKRS between 1998 and 2014. Results  A total of 97 postoperative histopathologically confirmed grade 2 meningiomas in 75 patients were treated and are included in this study. After a mean follow-up of 41 months, 28 meningiomas had local recurrence (29.79%). Median time to local recurrence was 89 months (mean: 69, range: 47-168). The 3- and 5-year actuarial local control (LC) rates were 68.9 and 55.7%, respectively. The 3- and 5-year overall survival rates were 88.6 and 81.1%, respectively. There was a trend toward worse LC with tumors treated with radiation doses ≤ 13 versus > 13 Gy. There was no radiation necrosis or second malignant tumors noted in our series. Conclusion  This report, one of the largest GKRS series for grade 2 meningiomas, demonstrates that GKRS is a safe and effective treatment modality for patients with grade 2 meningiomas with durable tumor control and minimal toxicity. Adjuvant GKRS could be considered as a reasonable treatment approach for patients with grade 2 meningiomas.

Abstract A064: IDO1 expression stratifies glioblastoma patient survival and correlates with dominantly immunosuppressive pathways

Purpose: The objective of this study was to evaluate the prognostic significance of the immunosuppressive molecule indoleamine 2, 3-dioxygenase (IDO1) mRNA expression in patients with low-grade glioma (LGG) and glioblastoma (GBM).

Experimental Design: Hi-RNA-seq. Illumina data mined from the cancer genome atlas (TCGA) reflecting 475 LGG (WHO grade II and III) and 172 GBM patients were utilized to characterize the pattern of IDO1 mRNA expression. Kaplan-Meier (KM) survival analysis and multivariate Cox proportional hazards regression were conducted to evaluate the significance of IDO1 expression as a stratification marker in glioma patients. mRNA expression of proinflammatory and immunosuppressive factor genes were also investigated for their correlation with IDO1 mRNA expression. Ivy GAP analysis was further utilized to localize IDO1 mRNA within different GBM anatomic niches.

Results: Expression profiling of the TCGA revealed a distinct pattern of progressively increasing IDO1 mRNA levels correlating with decreased survival both in LGG and GBM patients. In grade III LGG and GBM, IDO1 mRNA expression was significantly decreased when mutant isocitrate dehydrogenase 1 and 2 (mIDH1/2) was coincidently expressed when compared to samples with wild-type IDH1/2 expression (mean difference = 1.51, P &lt; 0.0001 in grade III; mean difference = 2.15, P &lt; 0.01 in GBM). KM analysis and multivariate Cox regression analysis found IDO1 mRNA expression levels to be an independent prognostic factor for survival among LGG (P = 0.0115; HR = 1.68) and GBM (P = 0.0076; HR = 1.82) patients. Pearson's correlation analysis identified significant associations among GBM between IDO1 and the genes encoding immunosuppressive factors including PD-L1 (r = 0.2993, P &lt; 0.0001), PD-L2 (r = 0.4871, P &lt; 0.0001), PD-1 (r = 0.3416, P &lt; 0.0001), CTLA-4 (r = 0.3534, P &lt; 0.0001), STAT3 (r = 0.2366, P = 0.0018), CD39 (r = 0.2691, P = 0.0004), BTLA (r = 0.2981, P &lt; 0.0001), Lag3 (r = 0.2567, P = 0.0007), FoxP3 (r = 0.1865, P &lt; 0.0143) and FGL2 (r = 0.4267, P &lt; 0.0001). Notably, IDO1 mRNA levels were higher in the cellular (1.398 ± 0.1257, mean ± SEM) and necrotic (1.543 ± 0.1489) GBM zones, when compared to infiltrating (0.9303 ± 0.0786) and leading margins (0.9064 ± 0.1224). Additionally, for the IDO1 paralog genes IDO2 and TDO2, which encodes indoleamine 2, 3-dioxygenase 2 and tryptophan dioxygenase respectively, no overall differential expression pattern were observed between different pathological grades nor a significant stratification in LGG and GBM patient survival.

Conclusions: Our data show for the first time that IDO1 mRNA levels can be used as an independent prognostic variable for patients with LGG and/or GBM. Given that ongoing IDO1-targeted immunotherapy clinical trials aim to inhibit enzymatic activity in malignant glioma, our data suggest that targeted subject enrollment may result in a better clinical response to therapy.

Citation Format: Lijie Zhai, Matthew Genet, Erik Ladomersky, Kristen Lauing, Meijing Wu, David Binder, Leo Kim, Jeremy Rich, Craig Horbinski, C. David James, Jeffrey A. Sosman, Orin Bloch, Derek A. Wainwright. IDO1 expression stratifies glioblastoma patient survival and correlates with dominantly immunosuppressive pathways [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A064.