Genomic analysis of human brain metastases treated with stereotactic radiosurgery reveals unique signature based on treatment failure

Stereotactic radiosurgery (SRS) has been shown to be efficacious for the treatment of limited brain metastasis (BM); however, the effects of SRS on human brain metastases have yet to be studied. We performed genomic analysis on resected brain metastases from patients whose resected lesion was previously treated with SRS. Our analyses demonstrated for the first time that patients possess a distinct genomic signature based on type of treatment failure including local failure, leptomeningeal spread, and radio-necrosis. Examination of the center and peripheral edge of the tumors treated with SRS indicated differential DNA damage distribution and an enrichment for tumor suppressor mutations and DNA damage repair pathways along the peripheral edge. Furthermore, the two clinical modalities used to deliver SRS, LINAC and GK, demonstrated differential effects on the tumor landscape even between controlled primary sites. Our study provides, in human, biological evidence of differential effects of SRS across BM's.

Transcriptomic and Proteomic Spatial Profiling of Pediatric and Adult Diffuse Midline Glioma H3 K27-Altered, Reveals Region Specific Differences and Limited Overlap between mRNA and Protein

Diffuse midline glioma, H3 K27 -altered (DMG-Alt) are highly aggressive malignancies of the central nervous system (CNS) that primarily affect the pediatric population. Large scale spatial transcriptomic studies have implicated that tumor microenvironmental landscape plays an important role in determining the phenotypic differences in tumor presentation and clinical course, however, data connecting overall transcriptomic changes to the protein level is lacking. The NanoString GeoMx™ Digital Spatial Profiler platform was used to determine the spatial transcriptomic and proteomic landscape in a cohort of both pediatric and adult H3 K27 -altered DMG biopsy samples. Three fluorescently labeled antibodies targeting immune cells (CD45), epithelial cells (PanCK), tumor cells ( H3 K27M ) and a nucleic acid stain (SYTO-13) were used to establish regions of interest (ROI) for genomic and proteomic analysis. We found genetic alterations within the tumor which can be delineated across patient age and spatial location. We show that the H3 K27M mutation itself has a profound impact on tumor cells transcriptomics and interestingly we found limited fidelity between overall transcriptome and proteome. Our data also validate the previously described OPC like precursor signature at the proteomic level and reveal a special shift in the signature based on the local TME composition.

Spatial transcriptomics in glioblastoma: is knowing the right zip code the key to the next therapeutic breakthrough?

Spatial transcriptomics, the technology of visualizing cellular gene expression landscape in a cells native tissue location, has emerged as a powerful tool that allows us to address scientific questions that were elusive just a few years ago. This technological advance is a decisive jump in the technological evolution that is revolutionizing studies of tissue structure and function in health and disease through the introduction of an entirely new dimension of data, spatial context. Perhaps the organ within the body that relies most on spatial organization is the brain. The central nervous system's complex microenvironmental and spatial architecture is tightly regulated during development, is maintained in health, and is detrimental when disturbed by pathologies. This inherent spatial complexity of the central nervous system makes it an exciting organ to study using spatial transcriptomics for pathologies primarily affecting the brain, of which Glioblastoma is one of the worst. Glioblastoma is a hyper-aggressive, incurable, neoplasm and has been hypothesized to not only integrate into the spatial architecture of the surrounding brain, but also possess an architecture of its own that might be actively remodeling the surrounding brain. In this review we will examine the current landscape of spatial transcriptomics in glioblastoma, outline novel findings emerging from the rising use of spatial transcriptomics, and discuss future directions and ultimate clinical/translational avenues.

Molecular Characterization and Treatment Approaches for Pediatric H3 K27-Altered Diffuse Midline Glioma: Integrated Systematic Review of Individual Clinical Trial Participant Data

Diffuse midline glioma (DMG), H3 K27-altered are highly aggressive, incurable central nervous system (CNS) tumors. The current standard palliative treatment is radiotherapy, with most children succumbing to the disease in less than one year from the time of diagnosis. Over the past decade, there have been significant advancements in our understanding of these heterogeneous tumors at the molecular level. As a result, most of the newer clinical trials offered utilize more targeted approaches with information derived from the tumor biopsy. In this systematic review, we used individual participant data from seven recent clinical trials published over the past five years that met our inclusion and exclusion criteria to analyze factors that influence overall survival (OS). We found that the most prominent genetic alterations H3.3 (H3F3A) and TP53 were associated with worse OS and that ACVR had a protective effect. In addition, re-irradiation was the only statistically significant treatment modality that showed any survival benefit. Our findings highlight some important characteristics of DMG, H3 K27-altered and their effects on OS along with the importance of continuing to review clinical trial data to improve our therapies for these fatal tumors.

GM-CSF and IL-7 fusion cytokine engineered tumor vaccine generates long-term Th-17 memory cells and increases overall survival in aged syngeneic mouse models of glioblastoma

Age-related immune dysfunctions, such as decreased T-cell output, are closely related to pathologies like cancers and lack of vaccine efficacy among the elderly. Engineered fusokine, GIFT-7, a fusion of interleukin 7 (IL-7) and GM-CSF, can reverse aging-related lymphoid organ atrophy. We generated a GIFT-7 fusokine tumor vaccine and employed it in aged syngeneic mouse models of glioblastoma and found that peripheral vaccination with GIFT-7TVax resulted in thymic regeneration and generated durable long-term antitumor immunity specifically in aged mice. Global cytokine analysis showed increased pro-inflammatory cytokines including IL-1β in the vaccinated group that resulted in hyperactivation of dendritic cells. In addition, GIFT-7 vaccination resulted in increased T-cell trafficking to the brain and robust Th-17 long-term effector memory T-cell formation. TCR-seq analysis showed increased productive frequency among detected rearrangements within the vaccinated group. Overall, our data demonstrate that aging immune system can be therapeutically augmented to generate lasting antitumor immunity.

Genomic Analysis of Human Brain Metastases Treated with Stereotactic Radiosurgery Under the Phase-II Clinical Trial (NCT03398694) Reveals DNA Damage Repair at the Peripheral Tumor Edge

Stereotactic Radiosurgery (SRS) is one of the leading treatment modalities for oligo brain metastasis (BM), however no comprehensive genomic data assessing the effect of radiation on BM in humans exist. Leveraging a unique opportunity, as part of the clinical trial (NCT03398694), we collected post-SRS, delivered via Gamma-knife or LINAC, tumor samples from core and peripheral-edges of the resected tumor to characterize the genomic effects of overall SRS as well as the SRS delivery modality. Using these rare patient samples, we show that SRS results in significant genomic changes at DNA and RNA levels throughout the tumor. Mutations and expression profiles of peripheral tumor samples indicated interaction with surrounding brain tissue as well as elevated DNA damage repair. Central samples show GSEA enrichment for cellular apoptosis while peripheral samples carried an increase in tumor suppressor mutations. There are significant differences in the transcriptomic profile at the periphery between Gamma-knife vs LINAC.

EPCO-32. HIGHLY MULTIPLEXED PROTEOGENOMIC SPATIAL PROFILING OF PEDIATRIC AND ADULT H3 K27-ALTERED DIFFUSE MIDLINE GLIOMAS

BACKGROUND

H3 K27-altered diffuse midline gliomas (DMG) are highly aggressive malignancies of the central nervous system that affect both pediatric and adult populations. The immune layout and genetic changes within the tumor microenvironment associated with these high-grade malignancies are thought to play an integral role in the phenotypic differences in tumor presentation and clinical course between both populations. Comparative landscapes between pediatric and adult DMGs is not known.

METHODS

The NanoString GeoMxTM Digital Spatial Profiler platform was used to determine the immune marker and genetic layout in a cohort of both pediatric and adult H3 K27-altered DMG tissue samples. 5 samples from each population were assessed in triplicates for a total of 30 samples. Three fluorescently labeled antibodies targeting immune cells (CD45), epithelial cells (PanCK), tumor cells (H3 K27M) and a nucleic acid stain (SYTO-13) were used to identify and separate out the various components within the tumor tissues from selected regions of interest. The resultant information was then pooled into libraries that were run through the NanoString spatial profiler and Illumina sequencing system to assess proteomics and gene expressions for both cohorts of samples.

RESULTS

Our data revealed that there were immune and genetic changes that were seen within both populations across multiple regions of interest within the tumor tissues. A number of immune cell types and protein markers exhibited significant difference between the pediatric and adult tissue cohorts.

CONCLUSION

The proteogenomic spatial analysis of pediatric and adult H3 K27-altered DMG shows different immune and genetic profiles which are proposed to contribute to the clinical differences between both populations. These observed differences may play a role in future treatments for H3 K27-altered DMG and further research is needed to explore this.

IMMU-29. PERIPHERAL VACCINATION WITH GIFT-7 SECRETING TUMOR CELLS AUGMENTS AGE RELATED THYMIC DECLINE AND IMPROVES SURVIVAL ACROSS MULTIPLE GLIOBLASTOMA MOUSE MODELS

Glioblastoma (GBM), the most common primary brain tumor in adults, has a dismal prognosis and nearly 100% recurrence rate. With a median age of diagnosis of 64, age associated immune dysfunction needs to be accounted for during treatment. Cannonically, immunotherapies target checkpoint signaling pathways in order to create T-cell populations that are resistant to exhaustion. Our lab has demonstrated that exhaustion is not the only factor at play regarding T-cell dysfunction, as patients with GBM have a robust CD8+CD28- effector population present both in the blood and tumor, possibly indicating T-cell senescence. Here we present research utilizing GIFT-7, a fusiokine combining GMCSF and IL-7, which has been demonstrated to combat age related thymic decline. To accurately understand this phenomenon in the context of aging all experiments were done in mice aged 52 weeks before intial tumor injection. We transfected the mouse glioma line GL261 cells to stably express and secrete GIFT-7 and injected 500k cells (GIFT7/VC) subcutaneously in the flank of B6 mice. This flank tumor allowed both for continued systemic administration of GIFT7, as well as immune exposure to the tumor similar to a vaccine model. After 4 weeks an intracranial challenge of normal GL261 cells was conducted and survival was monitored. Mice with GIFT-7 flanks had a larger population of CD3 and CD4 T-cells in their systemic circulation (p < .001 and p < .05 respectively). We also observed that the GIFT-7 flank mice demonstrated an increased tendency to have T-cells of all populations (CD3, CD4+, and CD8+) present within the brain. Finally, GIFT-7 flank mice survival was vastly improved with 60% of mice showing long term survival ( > 120 days) compared to 0 VC mice.

CTIM-33. SEXUAL DIMORPHISM OF HUMAN IMMUNE SYSTEM PREDICTS CLINICAL OUTCOMES IN GLIOBLASTOMA IMMUNOTHERAPY: A SYSTEMATIC REVIEW AND META-ANALYSIS

Biological differences based on sex have been documented throughout scientific literature. Glioblastoma, the most common primary malignant brain tumor in adults, has a male sex incidence bias, however, no clinical trial data examining differential effects of treatment between sexes currently exist. We analyzed genomic data, as well as clinical trials, to delineate the effect of sex on the immune system and glioblastoma outcome following immunotherapy. We found that, in general females possess enriched immunological signatures on gene set enrichment analysis, that also stratified patient survival when delineated by sex. Female glioblastoma patients treated with immunotherapy had a statistically significant survival advantage at the 1-year compared to males (RR = 1.15; p = 0.0241). This effect was even more pronounced in vaccine-based immunotherapy, (RR = 1.29; p = 0.0158). Our study shows a meaningful difference in the immunobiology between males and females that also influences overall response to immunotherapy in the setting of glioblastoma. Our study adds to a growing body of literature examining sex differences in male and female immunology. We demonstrate both using large scale omic data sets, as well as clinical trials, that female sexually dimorphic genes are tied to immunological responses, and that females have better outcomes during GBM immunotherapy treatments. This data is critical to better inform treatment practices and further crystalizes the need for balanced trial design and prospective reporting of sex as a variable across all GBM clinical trials.

Cluster analysis demonstrates co-existing sites of fragility fracture and associated comorbidities

We undertook cluster analysis in 11,003 patients who had sustained ≥ 1 fragility fracture, to find associations between fracture sites and comorbidities. We identified three distinct groups of fracture sites and four clusters of fractures and comorbidities. Knowledge of factors associated with fracture sites will aid prophylaxis in at-risk patients.

INTRODUCTION

Fragility fracture (FF) prevalence is increasing. Subsequent fractures lead to greater morbidity and mortality. Few data are available on the association between FF sites and comorbidities.

OBJECTIVES

1. Establish the most common sites of FF and clusters within patients. 2. Identify patterns of co-existing FF and associated comorbidities.

METHODS

We retrospectively reviewed clinical records of patients undergoing bone mineral density estimation at a district hospital in North-West England, 2004-2016, identifying those who had sustained ≥ 1 FF. Demographics, FF site(s), comorbidities, and medications were recorded. Cluster analysis was performed on fracture sites alone, and sites and comorbidities, using Jaccard similarity coefficient. Results were plotted on a dendrogram and divided into clusters.

RESULTS

Of 28,868 patients, 11,003 had sustained ≥ 1 FF, 84.6% female, with overall mean age 67.5 years and median T-score - 1.12 SD. FF of the forearm was more frequent (n = 5045), most commonly co-existing with tibia/fibula fractures. Three FF site clusters were identified: ankle and elbow; forearm, tibia/fibula, ribs and spine; and pelvis, femur and humerus. When including comorbidities, four clusters were identified: forearm, tibia/fibula, spine, associated with family history of FF, smoking, corticosteroids and bisphosphonates; pelvis associated with hyperparathyroidism, PMR, coeliac disease and HRT; femur and humerus associated with IBD and RA; and ribs associated with alcohol and hyperthyroidism.

CONCLUSION

Cluster analysis demonstrated three fracture site clusters, and four subgroups of FF sites and comorbidities. Cluster analysis is a novel method to evaluate comorbidities associated with FF sites. Knowledge of factors associated with FF sites will aid prophylaxis in at-risk patients.

DIPG-29. Highly multiplexed digital spatial profiling of the tumor immune environment of pediatric and adultH3 K27M-mutant diffuse midline gliomas

BACKGROUND: H3 K27M-mutant diffuse midline gliomas (DMGs) are highly aggressive malignancies of the central nervous system that affect both pediatric and adult populations. The immune layout and genetic changes within the tumor microenvironment associated with these high-grade malignancies are thought to play an integral role in the phenotypic differences in tumor presentation and clinical course between both populations. Comparative immune landscape between pediatric and adult DMGs is not known. METHODS: The NanoString GeoMxTM Digital Spatial Profiler platform was used to determine the immune marker and genetic layout in a cohort of both pediatric and adult H3 K27M-mutant DMG tissue samples. Three fluorescently labeled antibodies targeting immune cells (CD45), epithelial cells (PanCK), tumor cells (H3 K27M) and a nucleic acid stain (SYTO-13) were used to identify and separate out the various components within the tumor tissues from selected regions of interest. The resultant information was then pooled into libraries that were run through the Illumina sequencing system to assess gene expression and proteomics for both cohorts of samples. RESULTS: Our data revealed that there were immune and genetic marker changes that were seen within both populations across multiple regions of interest within the tumor tissues. A number of immune cell types and protein markers exhibited significant difference between the pediatric and adult tissue cohorts. CONCLUSION: The digital spatial analysis of pediatric and adult H3 K27M-mutant DMGs show different immune and genetic profiles which are proposed to contribute to the clinical differences between both populations. These observed differences may play a role in future treatments for H3 K27M-mutant DMGs and further research is needed to explore this.

POS1179 SYSTEMATIC LITERATURE REVIEW ON THE SCREENING AND PROPHYLAXIS OF CHRONIC AND OPPORTUNISTIC INFECTIONS

Background

Opportunistic and chronic infections can arise in the context of treatment used for Autoimmune Rheumatic Diseases (ARDs). Although it is recognized that screening procedures and prophylactic measures must be followed, clinical practice is largely heterogeneous, with relevant recommendations not currently developed or disparately located across the literature.

Objectives

To conduct a systematic literature review (SLR) focusing on the screening and prophylaxis of opportunistic and chronic infections in ARDs. This is preparatory work done by members of the respective EULAR task force (TF).

Methods

Following the EULAR standardised operating procedures, we conducted an SLR with the following 5 search domains; 1) Infection: infectious agents identifed by a scoping review and expert opinion (TF members), 2) Rheumatic Diseases: all ARDs, 3) Immunosuppression: all immunosuppressives/immunomodulators used in rheumatology, 4) Screening: general and specific (e.g mantoux test) terms, 5) Prophylaxis: general and specific (e.g trimethoprim) terms. Articles were retrieved having the terms from domains 1 AND 2 AND 3, plus terms from domains 4 OR 5. Databases searched: Pubmed, Embase, Cochrane. Exclusion criteria: post-operative infections, pediatric ARDs, not ARDs (e.g septic arthritis), not concerning screening or prophylaxis, Covid-19 studies, articles concerning vaccinations and non-Εnglish literature. Quality of studies included was assessed as follows: Newcastle Ottawa scale for non-randomized controlled trials (RCTs), RoB-Cochrane tool for RCTs, AMSTAR2 for SLRs.

Results

5641 studies were initially retrieved (Figure 1). After title and abstract screening and removal of duplicates, 568 full-text articles were assessed for eligibility. Finally, 293 articles were included in the SLR. Most studies were of medium quality. Reasons for exclusion are shown in Figure 1. Results categorized as per type of microbe, are as follows: For Tuberculosis; evidence suggests that tuberculin skin test (TST) is affected by treatment with glucocorticoids and conventional synthetic DMARDs (csDMARDs) and its performance is inferior to interferon gamma release assay (IGRA). Agreement between TST and IGRA is moderate to low. Conversion of TST/IGRA occurs in about 10-15% of patients treated with biologic DMARDs (bDMARDs). Various prophylactic schemes have been used for latent TB, including isoniazide for 9 months, rifampicin for 4 months, isoniazide/rifampicin for 3-4 months. For hepatitis B (HBV): there is evidence that risk of reactivation is increased in patients positive for hepatitis B surface antigen. These patients should be referred for HBV treatment. Patients who are positive for anti-HBcore antibodies, are at low risk for reactivation when treated with glucocorticoids, cDMARDs and bDMARDs but should be monitored periodically with liver function tests and HBV-viral load. Patients treated with rituximab display higher risk for HBV reactivation especially when anti-HBs titers are low. Risk for reactivation in hepatitis C RNA positive patients, treated with bDMARDs is low. However, all patients should be referred for antiviral treatment and monitored periodically. For pneumocystis jirovecii: prophylaxis with trimethoprim/sulfamethoxazole (alternatively with atovaquone or pentamidine) should be considered in patients treated with prednisolone: 15-30mg/day for more than 4 weeks. Few data exist for screening and prophylaxis from viruses like EBV, CMV and Varicella Zoster Virus. Expert opinion supports the screening of rare bugs like histoplasma and trypanosoma in patients considered to be at high risk (e.g living in endemic areas).

Figure 1.

SLR flowchart

Conclusion

The risk of chronic and opportunistic infections should be considered in all patients prior to treatment with immunosuppressives/immunomodulators. Different screening and prophylaxis approaches are described in the literature, partly determined by individual patient and disease characteristics. Collaboration between different disciplines is important.

Acknowledgements

We would like to thank all members of the EULAR Task Force for the screening and prophylaxis of chronic and opportunistic infections in Autoimmune Rheumatic Diseases.

Disclosure of Interests

None declared

POS1461 GIANT CELL ARTERITIS-RELATED STROKE IN A MAN WITH ELDERLY-ONSET RHEUMATOID ARTHRITIS

Background

Giant cell arteritis-related stroke is rare, with high early mortality and major morbidity in survivors.

Objectives

To increase the awareness of coexistence of giant cell arteritis-related stroke and rheumatoid arthritis.

Methods

A case report and discussion.

Results

A 73 year-old man with seronegative elderly-onset rheumatoid arthritis (EORA) presented to the emergency department (ED) with a one week history of frontal headache, vomiting and dizziness. He had multiple cardiovascular comorbidities and took multiple medications, including methotrexate and sulfasalazine. He also had long-standing history of thrombocytopenia without requiring any treatment. Neurological examination performed in the ED was unremarkable. His C-reactive protein (CRP) was 69mg/L and erythrocyte sedimentation rate (ESR) 82mm/hour. Computed tomography (CT) of the brain was normal. The headache settled with analgesia. A diagnosis of probable tension-type headache, with underlying active EORA, was made.

One month later, he presented to an ophthalmologist with recurrence of headache associated with visual disturbance and was diagnosed with giant cell arteritis (GCA). Both CRP (77mg/L) and ESR (85mm/hour) remained raised. Neither temporal artery biopsy nor temporal artery ultrasound were possible due to the coronavirus disease 2019 (COVID-19) pandemic. The headache and visual symptoms resolved completely a week after prednisolone 60mg daily was prescribed. In parallel, the CRP dropped to 2mg/L and ESR 16mm/hour. The patient’s glucocorticoid dose was then tapered. While on prednisolone 20mg daily, about 3 weeks later, he developed slurred speech and generalized weakness. Examination showed cerebellar signs and MRI brain showed acute cerebellar infarct. He was treated pragmatically as an atherosclerotic stroke with clopidogrel, and the steroid was rapidly tapered in view of absence of headache and normalization of inflammatory markers.

Four weeks later, he was noted to have persistent confusion and unsteadiness of gait. CRP was elevated at 92mg/L. An urgent positron emission tomography-CT (PET-CT) scan showed inflammation in the vertebral arteries [Figure 1] and cerebellar stroke. Prednisolone 40mg daily was restarted which led to a rapid improvement in his symptoms and normalization of inflammatory markers. The glucocorticoids were tapered in a slower manner this time.

Figure 1.

Fused axial image of a PET-CT scan demonstrating increased uptake in the region of the left vertebral artery within the vertebral foramen.

A diagnosis of GCA-related cerebellar stroke with vertebral vasculitis was made and, with glucocorticoids, the patient made a good clinical recovery. His inflammatory joints pain also improved in parallel.

Conclusion

Stroke or transient ischemic stroke are rare complications, reported in 2.8-16% of patients with active GCA. Most studies report strokes as occurring between the onset of GCA symptoms and 4 weeks after commencement of glucocorticoids1-3.

Vertebrobasilar territory is involved in 60–88% of cases of GCA-related stroke1-3. In contrast, the vertebrobasilar territory is affected only in 15-20% of atherosclerotic strokes1,2. One study reported fatal outcomes in 11 out of 40 patients (28%) with GCA-related stroke, 7 within 2-13 days of stroke2.

To conclude, this case demonstrates that high-dose glucocorticoids with slower tapering were able to control GCA-related stroke due to vertebral vasculitis in patient with EORA on background methotrexate and sulfasalazine.

References

[1]Gonzalez-Gay MA, Vazquez-Rodriguez TR, Gomez-Acebo I, et al. Strokes at time of disease diagnosis in a series of 287 patients with biopsy-proven giant cell arteritis. Medicine. 2009;88(4):227-35.

[2]de Boysson H, Liozon E, Larivière D, et al. Giant cell arteritis–related stroke: a retrospective multicenter case-control study. 2017;44(3):297-303.

[3]Pariente A, Guédon A, Alamowitch S, et al. Ischemic stroke in giant-cell arteritis: French retrospective study. 2019;99:48.

Acknowledgements

We would like to thank Dr Lenetta Boyce for providing the PET-CT images.

Disclosure of Interests

None declared

Diffuse Intrinsic Pontine Glioma: Molecular Landscape, Evolving Treatment Strategies and Emerging Clinical Trials

Diffuse intrinsic pontine glioma (DIPG) is a type of intrinsic brainstem glial tumor that occurs primarily in the pediatric population. DIPG is initially diagnosed based on clinical symptoms and the characteristic location on imaging. Histologically, these tumors are characterized by a heterogenous population of cells with multiple genetic mutations and high infiltrative capacity. The most common mutation seen in this group is a lysine to methionine point mutation seen at position 27 (K27M) within histone 3 (H3). Tumors with the H3 K27M mutation, are considered grade 4 and are now categorized within the H3 K27-altered diffuse midline glioma category by World Health Organization classification. Due to its critical location and aggressive nature, DIPG is resistant to the most eradicative treatment and is universally fatal; however, modern advances in the surgical techniques resulting in safe biopsy of the lesion have significantly improved our understanding of this disease at the molecular level. Genomic analysis has shown several mutations that play a role in the pathophysiology of the disease and can be targeted therapeutically. In this review, we will elaborate on DIPG from general aspects and the evolving molecular landscape. We will also review innovative therapeutic options that have been trialed along with new promising treatments on the horizon.

Surgical Neuro-Oncology

Gliomas are the most common intrinsic brain tumor in adults. Although maximal tumor resection improves survival, this must be balanced with preservation of neurologic function. Technological advancements have greatly expanded our ability to safely maximize tumor resection and design innovative therapeutic trials that take advantage of intracavitary delivery of therapeutic agents after resection. In this article, we review the role of surgical intervention for both low-grade and high-grade gliomas and the innovations that are driving and expanding the role of surgery in this therapeutically challenging group of malignancies.

Brain metastases: An update on the multi-disciplinary approach of clinical management

IMPORTANCE

Brain metastasis (BM) is the most common malignant intracranial neoplasm in adults with over 100,000 new cases annually in the United States and outnumbering primary brain tumors 10:1.

OBSERVATIONS

The incidence of BM in adult cancer patients ranges from 10-40%, and is increasing with improved surveillance, effective systemic therapy, and an aging population. The overall prognosis of cancer patients is largely dependent on the presence or absence of brain metastasis, and therefore, a timely and accurate diagnosis is crucial for improving long-term outcomes, especially in the current era of significantly improved systemic therapy for many common cancers. BM should be suspected in any cancer patient who develops new neurological deficits or behavioral abnormalities. Gadolinium enhanced MRI is the preferred imaging technique and BM must be distinguished from other pathologies. Large, symptomatic lesion(s) in patients with good functional status are best treated with surgery and stereotactic radiosurgery (SRS). Due to neurocognitive side effects and improved overall survival of cancer patients, whole brain radiotherapy (WBRT) is reserved as salvage therapy for patients with multiple lesions or as palliation. Newer approaches including multi-lesion stereotactic surgery, targeted therapy, and immunotherapy are also being investigated to improve outcomes while preserving quality of life.

CONCLUSION

With the significant advancements in the systemic treatment for cancer patients, addressing BM effectively is critical for overall survival. In addition to patient's performance status, therapeutic approach should be based on the type of primary tumor and associated molecular profile as well as the size, number, and location of metastatic lesion(s).

Sexual dimorphism of the immune system predicts clinical outcomes in glioblastoma immunotherapy: A systematic review and meta-analysis

Background

Biological differences based on sex have been documented throughout the scientific literature. Glioblastoma (GBM), the most common primary malignant brain tumor in adults, has a male sex incidence bias, however, no clinical trial data examining differential effects of treatment between sexes currently exists.

Method

We analyzed genomic data, as well as clinical trials, to delineate the effect of sex on the immune system and GBM outcome following immunotherapy.

Results

We found that in general females possess enriched immunological signatures on gene set enrichment analysis, which also stratified patient survival when delineated by sex. Female GBM patients treated with immunotherapy had a statistically significant survival advantage at the 1-year compared to males (relative risk [RR] = 1.15; P = .0241). This effect was even more pronounced in vaccine-based immunotherapy (RR = 1.29; P = .0158).

Conclusions

Our study shows a meaningful difference in the immunobiology between males and females that also influences the overall response to immunotherapy in the setting of GBM.

Neuroinflammation in Autoimmune Disease and Primary Brain Tumors: The Quest for Striking the Right Balance

According to classical dogma, the central nervous system (CNS) is defined as an immune privileged space. The basis of this theory was rooted in an incomplete understanding of the CNS microenvironment, however, recent advances such as the identification of resident dendritic cells (DC) in the brain and the presence of CNS lymphatics have deepened our understanding of the neuro-immune axis and revolutionized the field of neuroimmunology. It is now understood that many pathological conditions induce an immune response in the CNS, and that in many ways, the CNS is an immunologically distinct organ. Hyperactivity of neuro-immune axis can lead to primary neuroinflammatory diseases such as multiple sclerosis and antibody-mediated encephalitis, whereas immunosuppressive mechanisms promote the development and survival of primary brain tumors. On the therapeutic front, attempts are being made to target CNS pathologies using various forms of immunotherapy. One of the most actively investigated areas of CNS immunotherapy is for the treatment of glioblastoma (GBM), the most common primary brain tumor in adults. In this review, we provide an up to date overview of the neuro-immune axis in steady state and discuss the mechanisms underlying neuroinflammation in autoimmune neuroinflammatory disease as well as in the development and progression of brain tumors. In addition, we detail the current understanding of the interactions that characterize the primary brain tumor microenvironment and the implications of the neuro-immune axis on the development of successful therapeutic strategies for the treatment of CNS malignancies.

Intraoperative Mass Spectrometry Platform for IDH Mutation Status Prediction, Glioma Diagnosis, and Estimation of Tumor Cell Infiltration

BACKGROUND

Surgical tumor resection is the primary treatment option for diffuse glioma, the most common malignant brain cancer. The intraoperative diagnosis of gliomas from tumor core samples can be improved by use of molecular diagnostics. Further, residual tumor at surgical margins is a primary cause of tumor recurrence and malignant progression. This study evaluates a desorption electrospray ionization mass spectrometry (DESI-MS) system for intraoperative isocitrate dehydrogenase (IDH) mutation assessment, estimation of tumor cell infiltration as tumor cell percentage (TCP), and disease status. This information could be used to enhance the extent of safe resection and so potentially improve patient outcomes.

METHODS

A mobile DESI-MS instrument was modified and used in neurosurgical operating rooms (ORs) on a cohort of 49 human subjects undergoing craniotomy with tumor resection for suspected diffuse glioma. Small tissue biopsies (ntotal = 203) from the tumor core and surgical margins were analyzed by DESI-MS in the OR and classified using univariate and multivariate statistical methods.

RESULTS

Assessment of IDH mutation status using DESI-MS/MS to measure 2-hydroxyglutarate (2-HG) ion intensities from tumor cores yielded a sensitivity, specificity, and overall diagnostic accuracy of 89, 100, and 94%, respectively (ncore = 71). Assessment of TCP (categorized as low or high) in tumor margin and core biopsies using N-acetyl-aspartic acid (NAA) intensity provided a sensitivity, specificity, and accuracy of 91, 76, and 83%, respectively (ntotal = 203). TCP assessment using lipid profile deconvolution provided sensitivity, specificity, and accuracy of 76, 85, and 81%, respectively (ntotal = 203). Combining the experimental data and using PCA-LDA predictions of disease status, the sensitivity, specificity, and accuracy in predicting disease status are 63%, 83%, and 74%, respectively (ntotal = 203).

CONCLUSIONS

The DESI-MS system allowed for identification of IDH mutation status, glioma diagnosis, and estimation of tumor cell infiltration intraoperatively in a large human glioma cohort. This methodology should be further refined for clinical diagnostic applications.

OMRT-9. Effect of Pre-Operative Stereotactic Radiosurgery on Brain Metastasis: Analysis of DNA and RNA Genomic Profiles from Phase-II Clinical Trial NCT03398694

Background

With improved systemic therapy that has limited impact on the intracranial compartment, the incidence of brain metastasis (BM) from solid cancers is rising and negatively impacting patient’s overall survival (OS). Treatment varies based on presentation, however, for patients with <4 symptomatic BMs current clinical practice involves surgical resection followed by stereotactic radiosurgery (SRS) to the resection cavity. Post-operative SRS is associated with increased risk of leptomeningeal disease (LMD) and local recurrence in the follow-up period. We hypothesize that pre-operative SRS will decrease the incidence of LMD as well as local recurrence and increase patient’s OS by delivering a lethal dose of radiation to tumor cells before they are disturbed by surgical resection. In a Phase II clinical trial (NCT03398694) we are treating patients with 1–4 symptomatic BMs with pre-operative SRS while collecting DNA and RNA sequencing data from core and peripheral edges of the resected tumor to examine the genomic effects of SRS on tumor.

Methods

Post-SRS resected tumor specimens were divided into two groups: ‘center’ and ‘periphery’ with respect to the center of SRS treatment with periphery within 50% isodose line. Previously resected untreated BMs were used as control. DNA and RNA were isolated from all samples for sequencing.

Conclusions

Our initial analyses show that pre-treatment with SRS, results in significant genomic changes at DNA and RNA levels throughout the tumor, in both center as well as periphery. Furthermore, significant transcriptomic differences were noted among matched samples between the central and peripheral SRS locations implicating differential effect of SRS dosing within a tumor. Initial gene ontological analysis on non-small cell lung cancer samples demonstrated an overexpression of WNT and BMP signaling pathways (p <.001, p<.01). These pathways are typically involved in neuronal development, hinting that adaptation to the brain microenvironment was occurring post SRS treatment.

Aging- and Tumor-Mediated Increase in CD8+CD28- T Cells Might Impose a Strong Barrier to Success of Immunotherapy in Glioblastoma

Clinical use of various forms of immunotherapeutic drugs in glioblastoma (GBM), has highlighted severe T cell dysfunction such as exhaustion in GBM patients. However, reversing T cell exhaustion using immune checkpoint inhibitors in GBM clinical trials has not shown significant overall survival benefit. Phenotypically, CD8⁺ T cells with downregulated CD28 coreceptors, low CD27 expression, increased CD57 expression, and telomere shortening are classified as senescent T cells. These senescent T cells are normally seen as part of aging and also in many forms of solid cancers. Absence of CD28 on T cells leads to several functional irregularities including reduced TCR diversity, incomplete activation of T cells, and defects in Ag-induced proliferation. In the context of GBM, presence and/or function of these CD8⁺CD28^- T cells is unknown. In this clinical correlative study, we investigated the effect of aging as well as tumor microenvironment on CD8⁺ T cell phenotype as an indicator of its function in GBM patients. We systematically analyzed and describe a large population of CD8⁺CD28^- T cells in both the blood and tumor-infiltrating lymphocytes of GBM patients. We found that phenotypically these CD8⁺CD28^- T cells represent a distinct population compared with exhausted T cells. Comparative transcriptomic and pathway analysis of CD8⁺CD28^- T cell populations in GBM patients revealed that tumor microenvironment might be influencing several immune related pathways and thus further exaggerating the age associated immune dysfunction in this patient population.

AB0649 INFECTION PROFILE OF IMMUNE-MODULATORY DRUGS USED IN AUTOIMMUNE DISEASES: ANALYSIS OF SUMMARY OF PRODUCT CHARACTERISTIC DATA

Background:

The number of immune-modulatory drugs used to treat immune-mediated inflammatory diseases (IMIDs) has exponentially increased in recent decades. While effective in controlling disease, serious infection remains a concern.

Accurate information on immune-modulatory drugs, including infections, is required to guide prescribing decisions. The “summary of product characteristics” (SmPC) by the European Medicines Agency (EMA) provides a useful repository of information on adverse events e.g. infections, from clinical trials and post-marketing pharmacovigilance (1).

To date, no comparison has been undertaken on reported infection frequencies across SmPCs for immune-modulators.

Objectives:

To compare infection frequency, site and type across the most commonly-prescribed immune-modulatory drugs used to treat IMIDs, using information provided by SmPCs.

Methods:

A drug was included if licensed in Europe for treatment of one of the following: rheumatoid arthritis, axial spondyloarthritis, connective tissue disease, autoimmune vasculitis, autoinflammatory syndromes, inflammatory bowel disease (Crohn’s and ulcerative colitis), psoriasis, multiple sclerosis and other rarer conditions.

The Electronic Medicines Compendium (EMC) was searched for commonly prescribed immune-modulatory drugs used for the above indications. SmPC documents were manually searched for information on infection frequency, extracted from sections 4.4 and 4.8. Infection frequency was recorded as per convention in the SmPC: very common (≥1/10); common (≥1/100 to <1/10); uncommon (≥1/1,000 to <1/100); rare (≥1/10,000 to <1/1,000); very rare (<1/10,000) (1), for each drug. Information was further extracted on infection site (e.g. respiratory, skin etc), type (e.g. bacterial, viral etc) and individual pathogenic organisms.

25% of included SmPCs were screened and extracted by a second reviewer. Disagreements were resolved with input from a third reviewer.

Results:

In total, 39 drugs were included, used across 20 indications: nine conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs), six targeted synthetic DMARDs (tsDMARDs; four Janus kinase [JAK] inhibitors, two sphingosine 1-phosphate receptor modulators) and 24 biologic DMARDs (17 cytokine-targeted; seven cell-targeted).

Twelve sites of infection were recorded. Minimal or no site information was available for most csDMARDs and siponimod, certolizumab pegol and rituximab. The most common sites of infection are listed by drug group in Figure 1. Upper respiratory tract was the most common site, especially with bDMARDs. Lower respiratory, ear/nose/throat (including sinusitis) and urinary tract infections were moderately common, with clustering within drug groups. No drugs reported risk of cardiac infections; the eye, musculoskeletal, neurological, oral and reproductive sites were the least commonly-reported sites of infection.

Infection data for 27 distinct pathogens were recorded, the majority viruses, especially with bDMARD use. Herpes simplex and zoster were the most frequently listed (mainly with bDMARDs and tsDMARDs), followed by influenza. Common non-viral causes of infection were candida and tinea species.

Variable or absent reporting was noted for opportunistic infections (e.g. tuberculosis and fungi) and certain high-prevalence viruses e.g. Epstein-Barr.

Conclusion:

The SmPC literature reports differences in infection risk, by site and pathogen, between immune-modulatory drugs. The findings can be used to visualise differences and aid treatment decisions. However, some of the patterns we have shown lack face-validity to clinicians familiar with real-world safety data. The data fail to capture risk of rare infections, are likely skewed by trial selection criteria, varying number of trials per drug and quirks of individual study-reporting methodologies.

The findings highlight the need for robust post-marketing pharmacovigilance studies.

References:

[1]A Guideline on Summary of Product Characteristics Module 1.3. 2008.

Disclosure of Interests:

None declared.

Molecular Classification of Gliomas is Associated with Seizure Control: A Retrospective Analysis

Classically, histologic grading of gliomas has been used to predict seizure association, with low-grade gliomas associated with an increased incidence of seizures compared to high-grade gliomas. In 2016, WHO reclassified gliomas based on histology and molecular characteristics. We sought to determine whether molecular classification of gliomas is associated with preoperative seizure presentation and/or post-operative seizure control across multiple glioma subtypes. All gliomas operated at our institution from 2007 to 2017 were identified based on ICD 9 and 10 billing codes and were retrospectively assessed for molecular classification of the IDH1 mutation, and 1p/19q codeletion. Logistic regression models were performed to assess associations of seizures at presentation as well as post-operative seizures with IDH status and the new WHO integrated classification. Our study included 376 patients: 82 IDH mutant and 294 IDH wildtype. The presence of IDH mutation was associated with seizures at presentation [OR 3.135 (1.818-5.404), p < 0.001]. IDH-mutant glioblastomas presented with seizures less often than other IDH-mutant glioma subtypes grade II and III [OR 0.104 (0.032-0.340), p < 0.001]. IDH-mutant tumors were associated with worse post-operative seizure outcomes, demonstrated by Engel Class [OR 2.666 (1.592-4.464), p < 0.001]. IDH mutation in gliomas is associated with an increased risk of seizure development and worse post-operative seizure control, in all grades except for GBM.

Genome wide DNA methylation landscape reveals glioblastoma's influence on epigenetic changes in tumor infiltrating CD4+ T cells

CD4+ helper T (Th) cells play a critical role in shaping anti-tumor immunity by virtue of their ability to differentiate into multiple lineages in response to environmental cues. Various CD4+ lineages can orchestrate a broad range of effector activities during the initiation, expansion, and memory phase of endogenous anti-tumor immune response. In this clinical corelative study, we found that Glioblastoma (GBM) induces multi- and mixed-lineage immune response in the tumor microenvironment. Whole-genome bisulfite sequencing of tumor infiltrating and blood CD4+ T-cell from GBM patients showed 13571 differentially methylated regions and a distinct methylation pattern of methylation of tumor infiltrating CD4+ T-cells with significant inter-patient variability. The methylation changes also resulted in transcriptomic changes with 341 differentially expressed genes in CD4+ tumor infiltrating T-cells compared to blood. Analysis of specific genes involved in CD4+ differentiation and function revealed differential methylation status of TBX21, GATA3, RORC, FOXP3, IL10 and IFNG in tumor CD4+ T-cells. Analysis of lineage specific genes revealed differential methylation and gene expression in tumor CD4+ T-cells. Interestingly, we observed dysregulation of several ligands of T cell function genes in GBM tissue corresponding to the T-cell receptors that were dysregulated in tumor infiltrating CD4+ T-cells. Our results suggest that GBM might induce epigenetic alterations in tumor infiltrating CD4+ T-cells there by influencing anti-tumor immune response by manipulating differentiation and function of tumor infiltrating CD4+ T-cells. Thus, further research is warranted to understand the role of tumor induced epigenetic modification of tumor infiltrating T-cells to develop effective anti-GBM immunotherapy.

A Comparison Between Chemo-Radiotherapy Combined With Immunotherapy and Chemo-Radiotherapy Alone for the Treatment of Newly Diagnosed Glioblastoma: A Systematic Review and Meta-Analysis

Background

Immunotherapy for GBM is an emerging field which is increasingly being investigated in combination with standard of care treatment options with variable reported success rates.

Objective

To perform a systematic review of the available data to evaluate the safety and efficacy of combining immunotherapy with standard of care chemo-radiotherapy following surgical resection for the treatment of newly diagnosed GBM.

Methods

A literature search was performed for published clinical trials evaluating immunotherapy for GBM from January 1, 2000, to October 1, 2020, in PubMed and Cochrane using PICOS/PRISMA/MOOSE guidelines. Only clinical trials with two arms (combined therapy vs. control therapy) were included. Outcomes were then pooled using weighted random effects model for meta-analysis and compared using the Wald-type test. Primary outcomes included 1-year overall survival (OS) and progression-free survival (PFS), secondary outcomes included severe adverse events (SAE) grade 3 or higher.

Results

Nine randomized phase II and/or III clinical trials were included in the analysis, totaling 1,239 patients. The meta-analysis revealed no statistically significant differences in group’s 1-year OS [80.6% (95% CI: 68.6%–90.2%) vs. 72.6% (95% CI: 65.7%–78.9%), p = 0.15] or in 1-year PFS [37% (95% CI: 26.4%–48.2%) vs. 30.4% (95% CI: 25.4%–35.6%) p = 0.17] when the immunotherapy in combination with the standard of care group (combined therapy) was compared to the standard of care group alone (control). Severe adverse events grade 3 to 5 were more common in the immunotherapy and standard of care group than in the standard of care group (47.3%, 95% CI: 20.8–74.6%, vs 43.8%, 95% CI: 8.7–83.1, p = 0.81), but this effect also failed to reach statistical significance.

Conclusion

Our results suggests that immunotherapy can be safely combined with standard of care chemo-radiotherapy without significant increase in grade 3 to 5 SAE; however, there is no statistically significant increase in overall survival or progression free survival with the combination therapy.

MR1 overexpression correlates with poor clinical prognosis in glioma patients

BACKGROUND

Glioblastoma is the most common adult primary brain tumor with near-universal fatality. Major histocompatibility complex (MHC) class I molecules are important mediators of CD8 activation and can be downregulated by cancer cells to escape immune surveillance. MR1 is a nonclassical MHC-I-like molecule responsible for the activation of a subset of T cells. Although high levels of MR1 expression should enhance cancer cell recognition, various tumors demonstrate MR1 overexpression with unknown implications. Here, we study the role of MR1 in glioma.

METHODS

Using multi-omics data from the Cancer Genome Atlas (TCGA), we studied MR1 expression patterns and its impact on survival for various solid tumors. In glioma specifically, we validated MR1 expression by histology, elucidate transcriptomic profiles of MR1 high versus low gliomas. To understand MR1 expression, we analyzed the methylation status of the MR1 gene and MR1 gene-related transcription factor (TF) expression.

RESULTS

MR1 is overexpressed in all grades of glioma and many other solid cancers. However, only in glioma, MR1 overexpression correlated with poor overall survival and demonstrated global dysregulation of many immune-related genes in an MR1-dependent manner. MR1 overexpression correlated with decreased MR1 gene methylation and upregulation of predicted MR1 promoter binding TFs, implying MR1 gene methylation might regulate MR1 expression in glioma.

CONCLUSIONS

Our in silico analysis shows that MR1 expression is a predictor of clinical outcome in glioma patients and is potentially regulated at the epigenetic level, resulting in immune-related genes dysregulation. These findings need to be validated using independent in vitro and in vivo functional studies.

44. EFFECT OF STEREOTACTIC RADIOSURGERY ON NON-SMALL CELL LUNG CANCER BRAIN METASTASIS: CONTINUED CORRELATIVE RADIOBIOLOGIC ANALYSIS OF DNA AND RNA GENOMIC PROFILES FROM PHASE-II CLINICAL TRIAL NCT03398694

BACKGROUND

Stereotactic radiosurgery (SRS) is an increasingly common modality used with or without surgery for the treatment of brain metastases (BM). However, the effects of SRS on tumors in vivo is unknown.

METHODS

Patients were treated with SRS prior to surgery as per clinical trial NCT03398694. Resected tumor was divided into two groups: ‘center’ and ‘periphery’ with respect to SRS treatment. Tissue were analyzed by DNA and RNA sequencing and compared between the two and to non-radiated tumor.

RESULTS

DNA analysis showed at the individual level, matched comparison of SRS samples from the center or periphery of the same tumor had mutational burden differences. RNA analysis revealed no differentially expressed genes between center and periphery, but there were 62 and 192 differentially expressed genes between the center or periphery and non-radiated control, respectively. At an individual level, matched center and periphery tumor had an average of 16641 differentially expressed genes. Comparing total number of up- and downregulated genes with SNP and Indel mutations of matched patient samples, in patients with higher mutational burdens in peripheral tumors as compared to center there was a higher number of upregulated genes. Reciprocally, when mutation burden was higher in center tumor, total number of genes that were either up- or downregulated were about the same. Pooled analysis revealed significant downregulation of oncogenes, such as TP63 and RECQL4, in the SRS group. DO enrichment analysis also revealed pathways related to NSCLC and lung carcinoma significantly altered in radiation cohort.

CONCLUSION

In summary, this study demonstrates that SRS alters the molecular and genomic profile of NSCLC BM. It results in downregulation of oncogenes and pathways related to lung cancer. Additionally, by sampling the tumor at the center and periphery, there are differential effects of the dose gradient on the cellular and molecular response to ionizing radiation.

OP0294 DIFFERENTIAL INFLUENCE OF CO-MORBIDITIES ON SITE OF FRAGILITY FRACTURES

Background:

Fragility fractures (FF) can occur at various sites of the skeleton, and are associated with multiple risk factors [1]. The prevalence of FF markedly increases with age. As the longevity of the population increases, so will the incidence of FF, and that of associated co-morbidities and risk factors. There are few data on co-morbidities associated with fractures at each site.

Objectives:

Identify associations of co-morbidities with sites of FF, by applying cluster analysis.

Methods:

We reviewed 28868 patients presenting for BMD estimation at a district general hospital in North West England, 2004-2016. We identified patients who had sustained one or more FF at time of presentation. Site(s) of FF were recorded for each patient, including femur, forearm, humerus, pelvis, ribs, spine, tibia or fibula. The following co-morbidities or treatments were recorded: excess alcohol consumption (previous or current); bisphosphonates; coeliac disease; family history of FF; hormone replacement therapy; hyperparathyroidism; hyperthyroidism; inflammatory bowel disease; polymyalgia rheumatica; rheumatoid arthritis; smoking (previous or current); corticosteroids (previous or current). Cluster analysis was performed on fracture sites and co-morbidities, using Jaccard similarity coefficient, and plotted on a dendrogram. Results were divided into an optimal number of clusters, derived using the elbow and silhouette methods.

Results:

11003 of 28868 patients had sustained one or more FF at time of BMD estimation. Overall, 84.6% patients were female, mean age 67.5years, and median T-score -1.12 SD. Cluster analysis was performed for FF sites and co-morbidities, with Jaccard similarity coefficients calculated. 4 clusters were identified (Figure 1): FF of forearm (n=5054), tibia/fibula (n=2617), spine (n=2352), associated with family history of FF, smoking, corticosteroids, and bisphosphonate treatment; FF of pelvis (n=300) associated with hyperparathyroidism, PMR, coeliac disease, and HRT; FF of femur (n=1181) and humerus (n=1131) associated with IBD and RA; FF of ribs (n=1022) associated with alcohol and hyperthyroidism.

Conclusion:

Cluster analysis demonstrated 4 distinct subgroups of FF sites and associated co-morbidities. To our knowledge, this is the first study applying cluster analysis to evaluate co-morbidities associated with FF sites. Risk factors may influence trabecular more than cortical bone, accounting for the difference in clusters. Knowledge of risk factors associated with FF site subgroups will aid prophylaxis and management in at-risk patients.

References:

[1]Kanis JA. Diagnosis of osteoporosis and assessment of fracture risk. Lancet (London, England). 2002 Jun 1;359(9321):1929–36

Disclosure of Interests:

Mrinalini Dey: None declared, Marwan Bukhari Speakers bureau: Bristol-Myers Squib, UCB celltech, Roche/Chugai, Pfizer, Abbvie, Merck, Mennarini, Sanofi-aventis, Eli-Lilly, Janssen, Amgen and Novartis.

OP0324 CLUSTERING OF FRAGILITY FRACTURES BY SITE IN PATIENTS REFERRED FOR BONE MINERAL DENSITY ESTIMATION: AN OBSERVATIONAL STUDY

Background:

Fragility fractures (FF) are those resulting from mechanical forces equivalent to a fall from standing height or less [1]. They most commonly occur in the spine (vertebrae), forearm, and femur, but also occur at other sites. Prevalence markedly increases with age, due to age-related and menopause-related bone loss. FF cause substantial pain and disability, and are associated with decreased life expectancy. While many studies have investigated risk factors associated with FF, there are few data on the association between FF sites in at-risk patients.

Objectives:

1. Establish the most common sites of FF in patients presenting for bone mineral density (BMD) estimation.

2. Identify patterns of co-existing FF in the above cohort by applying cluster analysis.

Methods:

We retrospectively reviewed the clinical records of 28868 patients presenting for BMD estimation at a district general hospital in North West England, 2004-2016, identifying those who had sustained one or more FF. Site(s) of FF were recorded for each patient, categorised as: ankle, elbow, femur, forearm, humerus, pelvis, ribs, spine, tibia or fibula (recorded as “tibfib”). Cluster analysis was performed on fracture sites, using Jaccard similarity coefficient. Results were plotted on a dendrogram and divided into clusters, as per results derived from elbow and silhouette cluster methods.

Results:

Out of 28868 patients presenting for BMD estimation, 11003 were identified as having sustained one or more FF. 84.6% patients were female, with overall mean age 67.5years and median T-score -1.12 SD. The most common site of FF was the forearm (n=5045), most commonly co-existing with fractures of the tibia or fibula. Frequencies of the most common and co-existing FF sites are shown in Figure 1 (top). Cluster analysis identified 3 clusters: ankle and elbow; forearm, tibia/fibula, ribs, and spine; pelvis, femur, and humerus. The second half of Figure 1 displays the dendrogram of cluster analysis results, with Jaccard similarity measure.

Conclusion:

We applied cluster analysis to a large cohort of patients presenting for BMD estimation. Our results are in keeping with previous studies demonstrating the FF to most commonly occur in the forearm, and in those with osteopenia (T-score -2.5 < -1 SD) [2]. To our knowledge, this is the first study to apply cluster analysis to sites of FF. Results may be due to differences in cortical and trabecular bone structure, and have potential to aid prevention, monitoring, and management in at-risk patients.

References:

[1]National Institute for Health and Care Excellence (NICE). Osteoporosis: assessing the risk of fragility fracture - Clinical Guideline (CG146). 2012;(August):1–14.

[2]Siris ES et al. Bone mineral density thresholds for pharmacological intervention to prevent fractures. Arch Intern Med. 2004 May 24;164(10):1108–12.

Disclosure of Interests:

Mrinalini Dey: None declared, Marwan Bukhari Speakers bureau: Bristol-Myers Squib, UCB celltech, Roche/Chugai, Pfizer, Abbvie, Merck, Mennarini, Sanofi-aventis, Eli-Lilly, Janssen, Amgen and Novartis.

AB0940 BIOMARKERS IN THE DIAGNOSIS OF ACUTE HOT JOINTS: AN EVALUATION OF RESEARCH INTEREST 1960-2018

Background:

The acute hot joint presentation is a common clinical emergency, often the result of crystal arthritis or trauma. However, all diagnoses can mimic septic arthritis, which should be excluded promptly due to the potential for rapid joint destruction and significant morbidity. The gold-standard test for septic arthritis is synovial fluid culture, which can take several days to perform. Meanwhile, patients are often admitted and given antimicrobials. Other specialties have made use of rapid biomarkers to exclude infection, for example, exclusion of empyema using pleural fluid pH and glucose [1]. Such biomarkers could reduce the need for lengthy hospital admissions and inappropriate antibiotic use in the acute hot joint presentation.

Objectives:

1.Evaluate research interest over time, on the use of diagnostic biomarkers in the acute hot joint presentation.

2.Compare research interest in the use of diagnostic biomarkers in acute hot native versus acute hot prosthetic joints.

Methods:

We performed a review of the number of publications reporting the use and diagnostic accuracy of biomarkers to exclude infection in the acute hot joint presentations. The database,Scopus, was searched for English-language studies (1946-2018) using search terms relating to septic arthritis, crystal arthritis, and diagnostic markers derived from synovial fluid/aspirate. The number of papers published per year on prosthetic joints only was also calculated. Therefore, the following were recorded for each year 1946-2018: total number of studies; prosthetic joints only; native joints only. Values were plotted, with polynomial trend-lines and R2calculated.

Results:

Our search yielded 2279 relevant studies in total (561 on prosthetic joints), published 1946-2018. Only 1 study was identified for the year 1946; the next recorded publication was in 1960. Therefore, this single study was excluded as an outlier. Results are presented in Figure 1. The number of studies on diagnostic biomarkers for acute hot joints continued to increase after 1960. From 2016, the number of studies conducted in prosthetic joints outnumbered those done in native joints. Polynomial trend-lines applied to the results showed studies on native acute hot joints are predicted to decline, while those in prosthetic joints will continue to increase.

Conclusion:

Reasons for an increasing number of studies on prosthetic compared to native acute hot joints include a narrower differential diagnosis in prosthetic joints, i.e. septic vs aseptic. In contrast, native acute hot joints may be the result of various causes including crystal arthritis, inflammatory arthritis, and trauma. Having a narrower differential diagnosis may facilitate diagnostic research in prosthetic joint presentations. Furthermore, incidence of prosthetic joint infection is also greater than that of native joint infection [2]. Nonetheless, the incidence of native joint infection is increasing [3]. This, and the lack of methods by which to rapidly distinguish native joint septic arthritis from non-infective causes, indicates that more research is required in this area.

References:

[1]Heffner JE et al. Pleural fluid chemical analysis in parapneumonic effusions. A meta-analysis. Am J Respir Crit Care Med. 1995 Jun;151(6):1700–8.

[2]Roerdink RL et al. The difference between native septic arthritis and prosthetic joint infections: A review of literature. J Orthop Surg (Hong Kong).

[3]Rutherford AI et al. A population study of the reported incidence of native joint septic arthritis in the United Kingdom between 1998 and 2013. Rheumatol (United Kingdom). 2016;55(12):2176–80.

Disclosure of Interests:

None declared

Psychiatric disorders, suicidality, and personality among young men by sexual orientation

Personality and its potential role in mediating risk of psychiatric disorders and suicidality are assessed by sexual orientation, using data collected among young Swiss men (n = 5875) recruited while presenting for mandatory military conscription. Mental health outcomes were analyzed by sexual attraction using logistic regression, controlling for five-factor model personality traits and socio-demographics. Homo/bisexual men demonstrated the highest scores for neuroticism-anxiety but the lowest for sociability and sensation seeking, with no differences for aggression-hostility. Among homo/bisexual men, 10.2% fulfilled diagnostic criteria for major depression in the past 2 weeks, 10.8% for ADHD in the past 12 months, 13.8% for lifetime anti-social personality disorder (ASPD), and 6.0% attempted suicide in the past 12 months. Upon adjusting (AOR) for personality traits, their odds ratios (OR) for major depression (OR = 4.78, 95% CI 2.81–8.14; AOR = 1.46, 95% CI 0.80–2.65) and ADHD (OR = 2.17, 95% CI = 1.31–3.58; AOR = 1.00, 95% CI 0.58–1.75) lost statistical significance, and the odds ratio for suicide attempt was halved (OR = 5.10, 95% CI 2.57–10.1; AOR = 2.42, 95% CI 1.16–5.02). There are noteworthy differences in personality traits by sexual orientation, and much of the increased mental morbidity appears to be accounted for by such underlying differences, with important implications for etiology and treatment.

Intraoperative detection of isocitrate dehydrogenase mutations in human gliomas using a miniature mass spectrometer

Knowledge of the isocitrate dehydrogenase (IDH) mutation status of glioma patients could provide insights for decision-making during brain surgery. However, pathology is not able to provide such information intraoperatively. Here we describe the first application of a miniature mass spectrometer (MS) to the determination of IDH mutation status in gliomas intraoperatively. The instrumentation was modified to be compatible with use in the operating room. Tandem MS was performed on the oncometabolite, 2-hydroxyglutarate, and a reference metabolite, glutamate, which is not involved in the IDH mutation. Ratios of fragment ion intensities were measured to calculate an IDH mutation score, which was used to differentiate IDH mutant and wild-type tissues. The results of analyzing 25 biopsies from 13 patients indicate that reliable determination of IDH mutation status was achieved (p = 0.0001, using the Kruskal-Wallis non-parametric test). With its small footprint and low power consumption and noise level, this application of miniature mass spectrometers represents a simple and cost-effective platform for an important intraoperative measurement. Graphical abstract.

Quality of life of parents of mentally-ill children: a systematic review and meta-analysis

AIMS

To examine the quality of life (QOL) of parents of children with a specific mental disorder (any age).

METHODS

Relevant articles were searched using different databases. Articles were included that compared the QOL of parents with mentally-ill children to parents of healthy controls or norm values or provided the required data for this comparison. A meta-analysis was conducted to obtain an overall mean effect size estimate. Additional analyses were performed to assess publication bias and moderation.

RESULTS

Twenty-six out of 10 548 articles met the pre-defined inclusion criteria. Most of these studies focused on attention-deficit/hyperactivity disorder or autism spectrum disorder, used clinical samples that mainly included males and young children and studied the QOL of mothers. The meta-analysis revealed that parents of mentally-ill children are experiencing a clinically relevant reduction in their QOL relative to parents of healthy children and norm values (g = -0.66).

CONCLUSIONS

The compromised QOL of parents of mentally-ill children needs to be considered and addressed by health professionals who are in contact with them. The paper provides insights into existing research gaps and suggests improvements for subsequent work.

Common Molecular Alterations in Canine Oligodendroglioma and Human Malignant Gliomas and Potential Novel Therapeutic Targets

Spontaneous canine (Canis lupus) oligodendroglioma (ODG) holds tremendous potential as an immunocompetent large animal model of human malignant gliomas (MG). However, the feasibility of utilizing this model in pre-clinical studies depends on a thorough understanding of the similarities and differences of the molecular pathways associated with gliomas between the two species. We have previously shown that canine ODG has an immune landscape and expression pattern of commonly described oncogenes similar to that of human MG. In the current study, we performed a comprehensive analysis of canine ODG RNAseq data from 4 dogs with ODG and 2 normal controls to identify highly dysregulated genes in canine tumors. We then evaluated the expression of these genes in human MG using Xena Browser, a publicly available database. STRING-database inquiry was used in order to determine the suggested protein associations of these differentially expressed genes as well as the dysregulated pathways commonly enriched by the protein products of these genes in both canine ODG and human MG. Our results revealed that 3,712 (23%) of the 15,895 differentially expressed genes demonstrated significant up- or downregulation (log2-fold change > 2.0). Of the 3,712 altered genes, ~50% were upregulated (n = 1858) and ~50% were downregulated (n = 1854). Most of these genes were also found to have altered expression in human MG. Protein association and pathway analysis revealed common pathways enriched by members of the up- and downregulated gene categories in both species. In summary, we demonstrate that a similar pattern of gene dysregulation characterizes both human MG and canine ODG and provide additional support for the use of the canine model in order to therapeutically target these common genes. The results of such therapeutic targeting in the canine model can serve to more accurately predict the efficacy of anti-glioma therapies in human patients.

BSCI-19. EFFECT OF STEREOTACTIC RADIOSURGERY ON NON-SMALL CELL LUNG CANCER BRAIN METASTASIS: CORRELATIVE RADIOBIOLOGIC ANALYSIS FROM PHASE-II CLINICAL TRIAL NCT03398694

BACKGROUND: Stereotactic radiosurgery (SRS) is an increasingly common modality used with or without surgery for brain metastases (BM). However, biological effect of SRS to tumors in vivois not known. METHODS: Patients were treated with SRS prior to surgery as per the clinical trial protocol. The resected tumor was divided into two groups: ‘center’ and ‘periphery’ with respect to the center of SRS treatment with periphery within 50%-isodose-line. Tissue was analyzed by whole exome sequencing (WES) and compared between the two groups as well as to non-radiated control tissues. RESULTS: All sequenced samples contained greater than 95% clean reads with an average read density of 100 base pairs and mapping efficiency of >99%. Preliminary analysis focused on SNP and Indel detection. In pooled groups with n=7 replicates there was no statistically significant differences in total mutation burden in either SNP’s or Indels compared between controls and both treatment locations. Delving deeper intronic, frameshift, missense, and nonsense mutations all also showed insignificant changes between controls and center or peripheral tumor locations (p >0.5, p >0.1, p >0.4, p >0.3 respectively) hinting that at a pooled biological level there are not significant mutational burdens between treatment locations. However, at the individual level, matched comparison of SRS samples originating from the center or periphery of the same tumor showed total mutational burden differences. 6 out of 7 (86%) patients showed decreased total number of indels in peripheral vs. center and 5 out of 7 (71%) patients showed decreased number of SNP’s in peripheral vs. center locations. CONCLUSION: Ultimately, these data demonstrate the power of matched patient controls over bulk analysis in order to elucidate smaller but possibly biologically meaningful effects, and point to a possible location dependency in treatment associated mutation burden within a single patient and single tumor that may be masked at a population level.

The role of the immune system in brain metastasis

Metastatic brain tumors are the most common brain tumors in adults. With numerous successful advancements in systemic treatment of most common cancer types, brain metastasis is becoming increasingly important in the overall prognosis of cancer patients. Brain metastasis of peripheral tumor is the result of complex interplay of primary tumor, immune system and central nervous system microenvironment. Once formed, brain metastases hide behind the blood brain barrier and become inaccessible to chemotherapies that are otherwise successful in targeting systemic cancer. The approval of immune checkpoint inhibitors for several common cancers such as advanced melanoma and lung cancers brings with it the opportunity and obligation to further understand the mechanisms of immunosuppression by tumors that spread to the brain as well as the interaction between the brain environment and tumor microenvironment. In this review paper we define the central role of the immune system in the development of brain metastases. We performed a comprehensive review of the literature to outline the molecular mechanisms of immunosuppression used by tumors and how the immune system interacts with the central nervous system to facilitate brain metastasis. In particular we discuss the tumor-type-specific mechanisms of metastasis of cancers that preferentially metastasize to the brain as well as the therapies that effectively modulate the immune response, such as immune checkpoint inhibitors and vaccines.

The Evolving Role of CD8+CD28- Immunosenescent T Cells in Cancer Immunology

Functional, tumor-specific CD8⁺ cytotoxic T lymphocytes drive the adaptive immune response to cancer. Thus, induction of their activity is the ultimate aim of all immunotherapies. Success of anti-tumor immunotherapy is precluded by marked immunosuppression in the tumor microenvironment (TME) leading to CD8⁺ effector T cell dysfunction. Among the many facets of CD8⁺ T cell dysfunction that have been recognized—tolerance, anergy, exhaustion, and senescence—CD8⁺ T cell senescence is incompletely understood. Naïve CD8⁺ T cells require three essential signals for activation, differentiation, and survival through T-cell receptor, costimulatory receptors, and cytokine receptors. Downregulation of costimulatory molecule CD28 is a hallmark of senescent T cells and increased CD8⁺CD28⁻ senescent populations with heterogeneous roles have been observed in multiple solid and hematogenous tumors. T cell senescence can be induced by several factors including aging, telomere damage, tumor-associated stress, and regulatory T (Treg) cells. Tumor-induced T cell senescence is yet another mechanism that enables tumor cell resistance to immunotherapy. In this paper, we provide a comprehensive overview of CD8⁺CD28⁻ senescent T cell population, their origin, their function in immunology and pathologic conditions, including TME and their implication for immunotherapy. Further characterization and investigation into this subset of CD8⁺ T cells could improve the efficacy of future anti-tumor immunotherapy.

Efficacy of pre-operative stereotactic radiosurgery followed by surgical resection and correlative radiobiological analysis for patients with 1-4 brain metastases: study protocol for a phase II trial

BACKGROUND

Stereotactic radiosurgery (SRS) has emerged as a common adjuvant modality used with surgery for resectable brain metastases (BMs). However, the optimal sequence of the multi-modality therapy has not been established. The goal of the study is to evaluate 6-month local control utilizing pre-operative SRS followed by surgical resection for patients with 1-4 brain metastases.

METHODS

This prospective, single arm, phase II trial will recruit patients with up to 4 brain metastases and at least one resectable lesion. All lesions will be treated with SRS and symptomatic lesions will be resected within 1-4 days after SRS. Patients will be monitored for 6-month local control, in-brain progression free survival, distant in-brain failure, rate of leptomeningeal spread, radiation necrosis and overall survival. Additionally, we will also perform correlative radiobiological molecular studies to assess the effect of radiation dosing on the tumor tissue and clinical outcomes. We expect that pre-operative SRS to the gross tumor prior to surgical resection will improve local control and decrease leptomeningeal failure.

DISCUSSION

Our study is the second prospective trial to investigate the efficacy of pre-operative SRS in the treatment of multiple BMs. In addition, the correlative molecular studies will be the first to investigate early response of BMs at a cellular and genetic level in response to radiation doses and potentially provide molecular prognostic markers for local control and overall survival.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT03398694 (registration date: January 12, 2018).

CART Immunotherapy: Development, Success, and Translation to Malignant Gliomas and Other Solid Tumors

T cell chimeric antigen receptor (CAR) technology has allowed for the introduction of a high degree of tumor selectivity into adoptive cell transfer therapies. Evolution of this technology has produced a robust antitumor immunotherapeutic strategy that has resulted in dramatic outcomes in liquid cancers. CAR-expressing T-cells (CARTs) targeting CD19 and CD20 have been successfully used in the treatment of hematologic malignancies, producing sustained tumor regressions in a majority of treated patients. These encouraging results have led to a historic and unprecedented FDA approval of CTL019, Novartis' CAR T-cell therapy for the treatment of children and young adults with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). However, the translation of this technology to solid tumors, like malignant gliomas (MG), has thus far been unsuccessful. This review provides a timely analysis of the factors leading to the success of CART immunotherapy in the setting of hematologic malignancies, barriers limiting its success in the treatment of solid tumors, and approaches to overcome these challenges and allow the application of CART immunotherapy as a treatment modality for refractory tumors, like malignant gliomas, that are in desperate need of effective therapies.

Abstract 3782: Transcriptional regulation of MHC Class II in tumor associated plasmacytoid dendritic cells in glioblastoma

Background: Glioblastoma (GBM), an aggressive grade IV astrocytoma, is the most common primary brain tumor in adults and carry very poor prognosis. One of the hallmark features of GBM is tumor induced dense immunosuppression that renders immunotherapeutic strategies against GBM ineffective. In order to develop successful immunotherapeutic strategies for GBM, it is critical to understand the mechanism of immunosuppression in the tumor microenvironment (TME). In our previous publication, we have shown that plasmacytoid dendritic cells (pDCs) accumulate in TME and preferentially up-regulate MHC-II expression in comparison to myeloid DCs (mDCs). GBM infiltrating pDCs are immunosuppressive in nature and lack the ability to secrete IFN-alpha, and MHC-II upregulation by immunosuppressive pDCs lead to development of tumor tolerance. MHC-II molecules are transcriptionally regulated by the multiprotein complex enhanceosome consisting of a catalytic Class II transactivator (C2ta) in a cell type-dependent mechanism. There are no studies clearly showing differential enhanceosome and C2ta regulation in GBM associated pDC and mDC. In the present study, we investigated the mechanism of differential expression of enhanceosome multiprotein complex in GBM associated pDC and mDC and identify the upstream regulators and downstream effectors. Methods: GL261 cells were intracranially injected (i.c.) in C57BL6 mice and allowed to establish tumors. Tumor and normal brain (n=5), along with cervical lymph nodes (cLN), were collected and processed for isolation of pDC and mDC using flow sorting. Quantitative RT-PCR analysis was used to determine the enhanceosome components. IHC/IF and Western blot analysis were performed to confirm differential expression of enhanceosome components in mouse and human GBM specimens. Cytokine/chemokine protein array and ELISA methods were used to determine the differential expression of cytokines/chemokines in pDC and mDC. Results: We found differential expression of enhanceosome components in tumor associated pDC compared to mDC. Additionally, we found that GBM derived cytokines regulate differential expression of enhanceosome in tumor associated pDC and mDCs. Conclusions: In conclusion results from our studies show that GBM microenvironment regulates differential expression of enhanceosome transcription factors in pDC compared to mDC in a cytokine dependent process. This in turn helps to maintain an immunosuppressive microenvironment for continued tumor growth.

Citation Format: Sreenivasulu Chintala, Brij N. Tewari, Mario Henriquez, Kaleigh Fetcko, Anna Filley, Mahua Dey. Transcriptional regulation of MHC Class II in tumor associated plasmacytoid dendritic cells in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3782.

Plasmacytoid dendritic cell in immunity and cancer

Plasmacytoid dendritic cells (pDCs) comprise a subset of dendritic cells characterized by their ability to produce large amount of type I interferon (IFN-I/α). Originally recognized for their role in modulating immune responses to viral stimulation, growing interest has been directed toward their contribution to tumorigenesis. Under normal conditions, Toll-like receptor (TLR)-activated pDCs exhibit robust IFN-α production and promote both innate and adaptive immune responses. In cancer, however, pDCs demonstrate an impaired response to TLR7/9 activation, decreased or absent IFN-α production and contribute to the establishment of an immunosuppressive tumor microenvironment. In addition to IFN-α production, pDCs can also act as antigen presenting cells (APCs) and regulate immune responses to various antigens. The significant role played by pDCs in regulating both the innate and adaptive components of the immune system makes them a critical player in cancer immunology. In this review, we discuss the development and function of pDCs as well as their role in innate and adaptive immunity. Finally, we summarize pDC contribution to cancer pathogenesis, with a special focus on primary malignant brain tumor, their significance in the era of immunotherapy and suggest potential strategies for pDC-targeted therapy.

The Effect of Pet Therapy and Artist Interactions on Quality of Life in Brain Tumor Patients: A Cross-Section of Art and Medicine in Dialog

With the evolution of modern medical treatment strategies, there also comes the realization that many times we reach a point where traditional goals of medical care, such as overall survival or disease-free survival, are not realistic goals for many patients facing devastating illnesses. One such disease is malignant primary brain tumors, known as malignant glioma (MG). With median survival of only 20.9 months following best available standard of care treatment strategies, including surgery, chemotherapy, radiation, and tumor treating fields, MG is one of the deadliest malignancies of the modern era. Along the course of treating patients with MG, clinicians often realize that traditional treatment therapies can at best provide incremental benefit of symptom management without any survival benefit. However, even in these difficult situations, it is possible to make significant positive changes in patients’ health-related quality of life (HRQoL) using creative, non-traditional interventions. In this paper, we describe the initial findings from our project that takes a unique approach to studying the intersections of clinical care and art by using pet therapy and art-making as interventions for patients diagnosed with brain tumors. Our preliminary findings suggest that pet therapy and the ability to reflect as well as speak about their journey through a life-altering disease significantly increases patients’ overall feeling of wellbeing and reduces anxiety about future uncertainty.

Predictors of fracture risk in patients with systemic lupus erythematosus

Objectives Bone loss in systemic lupus erythematosus is multifactorial. Recent studies demonstrate corticosteroids, previous fractures and increasing age decrease bone mineral density. The effect of body mass index and fat mass are less well characterized. We sought to determine fracture risk factors in patients undergoing dual-energy X-ray absorptiometry scanning at a district hospital in 2004-2015. Methods Standard dual-energy X-ray absorptiometry parameters were recorded, plus rheumatoid arthritis diagnosis, smoking status, alcohol consumption, family history of fractures, history of secondary operation and corticosteroid use. Data were analyzed using Fisher's exact test for categorical data and logistic regression for continuous data. Results One hundred and fifty patients (141 women, nine men) with SLE were included; 52 (34.6%) had sustained at least one fracture. Fracture risk increased with increased age, body mass index, fat mass and average tissue thickness, and decreased lean mass (adjusted for steroid use), as well as with smoking and rheumatoid arthritis. Increased femoral and vertebral bone mineral density conversely decreased fracture risk. Conclusion Our study suggests increased age, body mass index, fat mass, smoking and/or rheumatoid arthritis increase fracture risk in SLE patients. To our knowledge, this is the first demonstration of a correlation between increased fat mass, adjusted for steroid use and fracture risk, in adults, potentially indicating a differential effect of fat on bone metabolism and lessening of lean body mass.

Primary Central Nervous System Germ Cell Tumors: A Review and Update

IMPORTANCE

Primary central nervous system (CNS) germ cell tumors (GCT) are a heterogeneous group of tumors that are still poorly understood. In North America, GCTs comprise approximately 1% of primary brain tumors in pediatric and young adult patients. GCTs can occur as pure or mixed subtypes; they are divided into germinomas, which are the most common subtype, and non-germinomatous germ cell tumors (NGGCTs), which consist of approximately one-third of GCTs and include teratomas, embryonal carcinomas, choriocarcinomas, and yolk sac tumors.

OBSERVATIONS

While the etiology of primary CNS GCT is not entirely clear, the various subtypes are lineage-related and may involve progenitor germ cells that fail to migrate and become trapped in midline locations. Primary CNS GCT most commonly arises in the pineal region but also occur in other areas. Presenting symptoms can include headache, Parinaud syndrome, diabetes insipidus, precosious puberty, ataxia, or hemiparesis. Diagnosis of primary CNS GCTs can be difficult and is often delayed. Various imaging studies and tumor markers can assist in specific diagnosis. Treatment plans differ depending on the subtype of GCT and may vary among physicians and institutions. Germinomas have a favorable prognosis with a greater than 90% overall survival, while NGGCTs only have survival rates ranging from 40-70%.

CONCLUSIONS AND RELEVANCE

Germinomas seem to be most effectively treated with chemotherapy and radiation, while NGGCT usually require surgical resection, chemotherapy, and radiation with the exception of mature teratomas frequently curable with surgery alone. Gamma knife radiosurgery is a promising treatment that may be an effective additional treatment option. Cytogenic and molecular analyses are attempting to further specify the different GCT subtypes and are helping to direct the development of distinct therapeutic targets to improve treatment and prognosis.

A Survey of the Neuro-Oncology Landscape

The field of neuro-oncology is evolving rapidly. Many important advances have recently been reported, and other promising investigations have the potential to soon make substantial impacts in the field, especially in the areas of high-grade gliomas and brain metastases. We present an overview of the current status of this field, highlighting the key recent advances as well as representative work of key clinical investigations, since these concepts have the potential to influence clinical management if they are demonstrated to be safe and efficacious. This overview includes some work that has only appeared in abstract form in order to provide a timely understanding of how the field is actively changing and what may lie on the horizon. We focus on both medical and surgical neuro-oncology advances in this highly multidisciplinary subspecialty.