Long-term neurocognitive function and quality of life after multimodal therapy in adult glioma patients: a prospective long-term follow-up

PURPOSE

Multimodal therapies have significantly improved prognosis in glioma. However, in particular radiotherapy may induce long-term neurotoxicity compromising patients' neurocognition and quality of life. The present prospective multicenter study aimed to evaluate associations of multimodal treatment with neurocognition with a particular focus on hippocampal irradiation.

METHODS

Seventy-one glioma patients (WHO grade 1-4) were serially evaluated with neurocognitive testing and quality of life questionnaires. Prior to (baseline) and following further treatment (median 7.1 years [range 4.6-11.0] after baseline) a standardized computerized neurocognitive test battery (NeuroCog FX) was applied to gauge psychomotor speed and inhibition, verbal short-term memory, working memory, verbal and non-verbal memory as well as verbal fluency. Mean ipsilateral hippocampal radiation dose was determined in a subgroup of 27 patients who received radiotherapy according to radiotherapy plans to evaluate its association with neurocognition.

RESULTS

Between baseline and follow-up mean performance in none of the cognitive domains significantly declined in any treatment modality (radiotherapy, chemotherapy, combined radio-chemotherapy, watchful-waiting), except for selective attention in patients receiving chemotherapy alone. Apart from one subtest (inhibition), mean ipsilateral hippocampal radiation dose > 50 Gy (Dmean) as compared to < 10 Gy showed no associations with long-term cognitive functioning. However, patients with Dmean < 10 Gy showed stable or improved performance in all cognitive domains, while patients with > 50 Gy numerically deteriorated in 4/8 domains.

CONCLUSIONS

Multimodal glioma therapy seems to affect neurocognition less than generally assumed. Even patients with unilateral hippocampal irradiation with > 50 Gy showed no profound cognitive decline in this series.

Acquired Factor XIII Deficiency in Patients with Multiple Trauma

INTRODUCTION

Fibrin stabilizing factor (FXIII) plays a crucial role in blood clotting, tissue repair, and immune defense. FXIII deficiency after trauma can lead to prolonged wound healing due to persistent infections or coagulation disorders. The aim of this study was to describe the prevalence of acquired FXIII deficiency after trauma and to provide a description of the time-course changes of important coagulation parameters in relation to FXIII activity. In this context, patient characteristics, laboratory data, and treatment modalities were examined with respect to their influence on FXIII activity. Furthermore, the effects of in vitro administration of FXIII on clot firmness and outcomes in patients with severe traumatic brain injury were investigated.

PATIENTS AND METHODS

Two trauma cohorts (A and B) were examined prospectively in a two-center study, and another (cohort C) was examined retrospectively. In cohort A (trauma patients, n=880) routine laboratory tests were conducted, and FXIII activity was measured. In cohort B (polytrauma patients, n=26), additional clinical parameters were collected, and in-vitro FXIII administration and rotational thromboelastometry (ROTEM) analyses were performed. In cohort C (polytrauma patients with severe traumatic brain injury [sTBI], n=84), the impact of initially measured FXIII activity on clinical outcomes after sTBI was investigated using the modified Rankin Scale (mRS) at least 6 months after trauma.

RESULTS

The prevalence of FXIII activity <70% in cohort A was 12.4%, with significant differences in age, Hb, fibrinogen, and Hct levels, platelet count, aPTT, and INR (vs. prevalence of FXIII activity >70%). Cohort B showed a decrease in FXIII activity from 85% to 58% after 7 days. FXIII deficiency correlated with time after trauma, aPTT, and fibrinogen level, lactate, and Hb levels. In-vitro administration of FXIII showed a positive influence on clot firmness due to improved maximum clot firmness (MCF in FIBTEM) and reduced maximum lysis (ML in EXTEM). Finally, a significant difference in FXIII activity between patients after sTBI with good and poor clinical outcomes was observed 6 months after trauma.

CONCLUSION

We demonstrated that trauma-associated FXIII deficiency is a common coagulation disorder, with FXIII deficiency increasing further in the first 7 days after trauma, the period of early surgical care. In vitro administration of FXIII was able to demonstrate significant clot stabilizing effects. For trauma patients with sTBI, FXIII activity could serve as a prognostic parameter, as it differed significantly between patients with good and poor clinical outcomes.

Multimodale Therapie bei lokal fortgeschrittenem kutanem Plattenepithelkarzinom

Die Therapieoptionen für lokal fortgeschrittene oder metastasierte Plattenepithelkarzinome waren bisher stark begrenzt und nicht standardisiert. Durch die Zulassung des monoklonalen Antikörpers Cemiplimab, der gegen den programmed death-1-Rezeptor (PD-1) gerichtet ist, hat sich die Prognose der betroffenen Patienten deutlich gebessert, wobei z.T. anhaltende Komplettremissionen erzielt werden können.

In der vorgestellten Kasuistik wurde ein multimorbider, 81-jähriger Patient aufgrund eines ausgedehnten Plattenepithelkarzinoms frontoparietal mit Schädelkalotteninfiltration und Einbruch nach intrakraniell zunächst mit Cemiplimab behandelt. Immunvermittelte Nebenwirkungen sind nicht aufgetreten. Bei klinischer und radiologischer Remission wurde der Restbefund interdisziplinär operativ versorgt, wobei die defekte Schädelkalotte rekonstruiert wurde. Histologisch wurde eine pathologische Komplettremission des Plattenepithelkarzinoms nachgewiesen. 6 Monate postoperativ ergab sich kein Anhalt für ein Lokalrezidiv oder Metastasen.

Dieser Fall zeigt exemplarisch einen Patienten, der trotz seines hohen Alters und Ko-Morbidität von der Therapie mit Cemiplimab profitiert hat. Darüber hinaus demonstriert dieser Fall die Relevanz eines interdisziplinären/multimodalen Therapieregimes im Management dieser in der Inzidenz deutlich ansteigenden Tumorentität.

PATH-08. A COMPREHENSIVE GENOMIC STUDY OF 390 H3F3A-MUTANT PEDIATRIC-TYPE DIFFUSE HIGH-GRADE GLIOMAS WHO CNS GRADE 4

OBJECTIVES

Histone gene mutant malignant gliomas - H3K27-altered diffuse midline glioma (DMG) and diffuse hemispheric glioma (DHG) H3G34-mutant - occur in all age groups and can have significant variation in clinical outcomes. Here, we report comprehensive genomic profiling from one of the largest collections of H3F3A-mutant gliomas analyzed to date, identifying subsets defined by recurrently co-mutated genes.

METHODS

We identified 390 H3F3A-mutant diffuse gliomas WHO grade 4 (201 females and 189 males) that were profiled in the comprehensive genomic profiling program at Foundation Medicine between 2013-2020. Information from pathology reports, histopathology reviews, and clinical data was assessed.

RESULTS

Our cohort comprised 304 (77.9%) H3K27M-mutant DMG WHO grade 4 (156 females and 148 males) and 86 H3G34-mutant DHG (45 females and 41 males) with a median age of 20 years (1-74 years). H3K27M-mutant DMG distributed equally between pediatric and adult patients, with 52% of the patients older than 20 years, 30% older than 30 years, and 18% older than 40 years at the time of first diagnosis. Clonal FGFR1 hotspot mutations were exclusively detected in K27M-mutant DMG (n = 64/304, 21%; p=0.0001), with a significant association with a higher age at first diagnosis (median 32.5 years), and with a wide tumor distribution across the diencephalon. Additional genes which were significantly more frequently altered in K27M-mutant compared to G34-mutant diffuse gliomas included NF1 (31% vs. 8.1%; p=0.0001) and PIK3CA/PIK3R1 (27.9% vs. 15.1%; p=0.016). Conversely, targetable alterations of the cell-cycle pathway (CDK4/6 amplifications and CDKN2A/B deletions) were enriched in H3G34-mutant DHG (26%) compared to H3K27M-mutant DMG (7%). Potentially targetable PDGFR alterations were present in 32.5% of H3G34-mutant DHG and in 18% of H3K27M-mutant DMG.

CONCLUSIONS

These data expand our understanding of the tumor-specific molecular features of pediatric-type high-grade gliomas, identifying cohort sub-structure by recurrent co-mutations, which can inform diagnosis and clinical trial design.

SURG-11. AKT1 E17K AND NF2 MUTATIONS DOMINATE SPINAL MENINGIOMAS WHO GRADE 1 AND PRESENT DISTINCT TUMOR FEATURES

INTRODUCTION

While the mutational landscape of intracranial meningiomas has been extensively studied, our understanding of the molecular profile of spinal meningiomas (SM) remains incomplete. In this study, we correlate the molecular status with tumor features in a clinically well-characterized cohort.

METHODS

Samples from 50 patients (38 females and 12 males) with WHO grade 1 SM were collected. We performed next-generation sequencing (NGS) using an assay covering frequently mutated genes in meningiomas including AKT1, KLF4, NF2, PIK3CA, POLR2A, SMARCB1, SMARCE1, SMO, SUFU, and TRAF7. We correlated clinical and imaging data with the molecular tumor status.

RESULTS

AKT1 E17K mutations were detected in 15 (30%) and NF2 mutations in 32 (64%) patients. Both mutations were mutually exclusive. In contrast to AKT1-mutant intracranial meningiomas, AKT1-mutant SM only harbored a TRAF7 co-mutation in a single case. NF2-mutant meningiomas had a significant female predominance (n= 30/32, 94%) when compared to the balanced incidence of AKT1-mutant tumors (n= 7/15, 46.7%, p= 0.0006). The two groups demonstrated stark differences in the location: a thoracic localization was significantly more common in NF2-mutant meningiomas (n= 25/32, 78.1%, p= 0.0012), while meningiomas harboring an AKT1 mutation were predominantly located in the cervical spine (n= 11/15, 73.3%). Moreover, while a substantial proportion of NF2-mutant meningiomas developed in the dorsal location (n= 19/32, 59.3%), the vast majority of AKT1-mutant meningiomas (n= 13/15, 87%) arose ventral to the spinal cord. The histologic subtype of NF2-mutant meningiomas was variable, while all but one AKT1-mutant meningioma showed meningothelial histology (93.3%, p= 0.0001). All calcified meningiomas (n= 17) were NF2-mutant (p= 0.0002), whereas none of the AKT1-mutant meningiomas showed intratumoral calcifications.

CONCLUSIONS

Our findings support the central role of AKT1 and NF2 mutations in the molecular pathogenesis of WHO grade 1 SM. These mutations are mutually exclusive and are associated with distinct tumor and clinical features.

PATH-17. DISTINCT MOLECULAR SUBCLASSES OF H3F3A-WILDTYPE, EGFR-ALTERED PEDIATRIC-TYPE DIFFUSE MIDLINE GLIOMAS WHO CNS GRADE 4

OBJECTIVES

Histone gene H3K27-altered diffuse midline glioma (DMG) are malignant tumors that occur in all age groups. In this study, we report comprehensive genomic profiling from H3F3A-wildtype, EGFR-altered DMG, as a distinct and newly recognized subset of pediatric-type DMG.

METHODS

Tumors were profiled in the comprehensive genomic profiling (CGP) program at Foundation Medicine between 2013-2020. Information from pathology reports, histopathology review, and patient clinical data was assessed.

RESULTS

We collected demographic and genomic data from 39 pediatric patients with H3F3A-wildtype, EGFR-altered HGG (17 females, 22 males; median age: 8.5 years, range 1-18 years). Female patients were younger at first diagnosis compared to male (median age 7 years vs. 10 years). All cases were microsatellite stable (MSS). The EGFR alterations consisted of 30 mutations and 9 amplifications. The mutations were distributed across the entire gene with no clear hotspot location. Our genomic data converged to identify three distinct molecular patterns. The first and most common group contained TP53 mutations (n = 17, 43.5%), showed no association with patient sex (8 females, 9 males), contained ATRX mutations (n = 3) and CDKN2A deletions (n = 5); these tumors did not harbor pathogenic mutations in TERTp, PIK3CA/PIK3R1, BCOR/BCORL1, STAG2, or SETD2. The second group featured TERTp-mutant tumors (n = 10), were more common in males (70%), and often demonstrated additional mutations in PIK3CA/PIK3R1 (n = 4), BCOR/BCORL1 (n = 4), CDKN2A/B (n = 4), and SETD2 (n = 2). The third group (n = 12) lacked TERTp and TP53 mutations and had a heterogeneous spectrum of non-recurrent mutations, including one CDKN2A/B deletion.

CONCLUSIONS

We have identified three distinct molecular subclasses that defined specific genomic tumor subgroups in pediatric-type EGFR altered DMG. Overall, these data increase our understanding of the pathobiology of this DMG subset and can guide the design of clinical trials.

Multimodale Therapie bei lokal fortgeschrittenem kutanem Plattenepithelkarzinom

Die Therapieoptionen für lokal fortgeschrittene oder metastasierte Plattenepithelkarzinome waren bisher stark begrenzt und nicht standardisiert. Durch die Zulassung des monoklonalen Antikörpers Cemiplimab, der gegen den programmed death-1-Rezeptor (PD-1) gerichtet ist, hat sich die Prognose der betroffenen Patienten deutlich gebessert, wobei z.T. anhaltende Komplettremissionen erzielt werden können.

In der vorgestellten Kasuistik wurde ein multimorbider, 81-jähriger Patient aufgrund eines ausgedehnten Plattenepithelkarzinoms frontoparietal mit Schädelkalotteninfiltration und Einbruch nach intrakraniell zunächst mit Cemiplimab behandelt. Immunvermittelte Nebenwirkungen sind nicht aufgetreten. Bei klinischer und radiologischer Remission wurde der Restbefund interdisziplinär operativ versorgt, wobei die defekte Schädelkalotte rekonstruiert wurde. Histologisch wurde eine pathologische Komplettremission des Plattenepithelkarzinoms nachgewiesen. 6 Monate postoperativ ergab sich kein Anhalt für ein Lokalrezidiv oder Metastasen.

Dieser Fall zeigt exemplarisch einen Patienten, der trotz seines hohen Alters und Ko-Morbidität von der Therapie mit Cemiplimab profitiert hat. Darüber hinaus demonstriert dieser Fall die Relevanz eines interdisziplinären/multimodalen Therapieregimes im Management dieser in der Inzidenz deutlich ansteigenden Tumorentität.

PATH-37. DISTINCT GENOMIC SUBCLASSES OF HIGH-GRADE/PROGRESSIVE MENINGIOMAS: NF2-ASSOCIATED, NF2-EXCLUSIVE, AND NF2-AGNOSTIC

BACKGROUND

Genomic studies of high-grade/progressive meningiomas have reported a heterogeneous mutation spectrum. Here, we present a genomic survey of one of the largest multi-institutional cohorts of high-grade/progressive meningiomas to date.

METHODS

850 high-grade/progressive meningiomas, including 441 WHO grade 2 and 176 WHO grade 3 meningiomas and 220 progressive WHO grade 1 meningiomas, were tested as part of a clinical testing program by hybridization capture of 406 cancer-related genes. Information from histopathology review and patient clinical data was assessed.

RESULTS

Genomic analyses converged to identify at least three distinct patterns of biologically-aggressive meningiomas. The first and most common contained NF2-mutant tumors (n = 426, 50%), was associated with male sex (64.4%, p = 0.0001) and often harbored additional mutations in CDKN2A/B (24%), and the chromatin regulators ARID1A (9%), and KDM6A (6%). A second group (NF2-agnostic) featured TERTp (n = 56) or TP53 mutations (n = 25) and were either NF2-mutant or wild-type, and displayed no association with either sex. The remaining group generally lacked NF2 mutations, and accounted for 40% of the cases-with three subgroups. One consistent primarily of grade 3 lesions harboring alterations in chromatin regulators BAP1 (n = 22) or PBRM1 (n = 16). A second subgroup contained AKT1 (n = 26), PIK3CA (n = 14) and SMO (n = 7) mutant skull-based meningiomas, and a third mixed subgroup included 237 meningiomas with a heterogeneous spectrum of low frequency and non-recurrent alterations.

CONCLUSIONS

Our findings indicate that the patterns of genomic alterations in high-grade/progressive meningiomas commonly group into three different categories. The most common NF2-associated canonical group frequently harbored CDKN2A/B alterations, which is potentially amenable to targeted therapies. An NF2-agnostic group harbored frequent TERTp and TP53 mutations. The final subclass, distinct from the canonical NF2 mutant associated pathway, was partly characterized by BAP1/PBRM1 alterations (rhabdoid/papillary histology) or skull-base disease.

PATH-35. AKT1(E17K) MUTATIONS ARE FREQUENT GENOMIC EVENTS IN CERVICAL SPINAL MENINGIOMAS

INTRODUCTION

Spinal meningiomas represent about one-third of all spine tumors. To date, little is known about the molecular profile of spinal meningiomas and their clinical impact. In this study, we correlate clinical parameters with targeted sequencing findings in a well-characterized cohort of 42 patients with spinal meningiomas.

METHODS

Samples from 42 spinal meningiomas (31 females and 11 males) were collected. Targeted sequencing for AKT1 E17K hot spot mutations was performed. Furthermore, clinical and imaging data were collected and correlated with the AKT1 mutation status.

RESULTS

Gross total resection (Simpson grade I /II) was achieved in all patients. The mean follow-up period was 60 months (6 –288 months). None of the patients demonstrated a tumor recurrence. AKT1E17K mutations were detected in 8 patients (19%), in five male and three female patients (p= 0.019). Although the majority of resected meningiomas (n= 28, 66.6%) were located in the thoracic spine, meningiomas originating in the cervical spine harbored significantly more AKT1 E17K mutations (6 out of 14, p= 0.010). Notably, all AKT1 mutated meningiomas arose ventrally or ventrolaterally to the spinal cord. The histologic examination revealed a WHO Grade 1 in 36 meningiomas (85.7%): 21 meningothelial, 8 psammomatous, 5 transitional, 2 fibrous. The remaining six meningiomas were classified as atypical WHO grade 2. Remarkably, AKT1 E17K mutations were significantly related to a meningothelial subtype (p= 0.044).

CONCLUSIONS

Our molecular study demonstrates that AKT1 E17K mutations are a frequent genomic event in spinal meningiomas. The majority of AKT1 mutated meningiomas occurred in male patients, originate in the cervical spine, and exhibit meningothelial histology.

PATH-40. SPORADIC NF2 WILD-TYPE MULTIPLE MENINGIOMAS HARBOR DISTINCT DRIVER MUTATIONS

OBJECTIVE

Multiple meningiomas (MM) are rare and present a unique management challenge. While the mutational landscape of single meningiomas has been extensively studied, understanding the molecular pathogenesis of sporadic MM remains incomplete. The objective of this study is to elucidate the genetic features of sporadic MM.

METHODS

We identified nine patients with MM (n=19) defined as ≥2 spatially separated synchronous or metachronous meningiomas. We profiled genetic changes in these tumors using next-generation sequencing (NGS) assay that covers a large number of targetable and frequently mutated genes in meningiomas including AKT1, KLF4, NF2, PIK3CA/PIK3R1, POLR2A, SMARCB1, SMO, SUFU, TRAF7, and the TERT promoter.

RESULTS

Most of MM were WHO grade 1 (n= 16, 84.2%). Within individual patients, no driver mutation was shared between separate tumors. All but two cases harbored different hot spot mutations in known meningioma-driver genes like TRAF7 (n= 5), PIK3CA (n= 4), AKT1 (n= 3), POLR2A (n=1) and SMO (n= 1). Moreover, individual tumors differed in histologic subtype in 8/9 patients. The low frequency of NF2 mutations in our series stands in contrast to previous studies that included hereditary cases arising in the setting of neurofibromatosis type 2 (NF2).

CONCLUSIONS

Our findings provide evidence for genomic inter-tumor heterogeneity and an independent molecular origin of sporadic NF2 wild-type MM. Furthermore, these findings suggest that genetic characterization of each lesion is warranted in sporadic MM.

P04.14 Sporadic wild-type multiple meningiomas harbor distinct driver mutations

BACKGROUND

Multiple meningiomas (MM) are rare and present a unique management challenge. While the mutational landscape of single meningiomas has been extensively studied, understanding of the molecular pathogenesis of sporadic MM remains incomplete. The objective of this study is to elucidate the genetic features of sporadic MM.

MATERIAL AND METHODS

We identified eight patients with MM (n=17) defined as ≥2 spatially separated synchronous or metachronous meningiomas. We profiled genetic changes in these tumors using a next generation sequencing (NGS) assay that covers a large number of targetable and frequently mutated genes in meningiomas including AKT1, KLF4, NF2, PIK3CA/PIK3R1, POLR2A, SMARCB1, SMO, SUFU, TRAF7, and the TERT promoter.

RESULTS

Most of MM were WHO grade 1 (n= 14, 82.3%). Within individual patients, no driver mutation was shared between separate tumors. All but two cases harbored different hot spot mutations in known meningioma-driver genes like TRAF7 (n= 5), PIK3CA (n= 3), AKT1 (n= 3) and SMO (n= 1). Moreover, individual tumors differed in histologic subtype in 7/8 patients. The low frequency of NF2 mutations in our series stands in contrast to previous studies that included hereditary cases arising in the setting of neurofibromatosis type 2 (NF2).

CONCLUSION

Our findings provide evidence for genomic inter-tumor heterogeneity and an independent molecular origin of sporadic NF2 wild-type MM. Furthermore, these findings suggest that genetic characterization of each lesion is warranted in sporadic MM.

P04.09 Frequent inactivating mutations of PBRM1 in meningioma with papillary features

BACKGROUND

Papillary meningiomas (PM) are rare WHO grade III tumors that are associated with frequent recurrences and metastatic disease in spite of surgery and radiation. Due to their low incidence and scarcity of tumor tissues available for genomic analyses, the genetic alterations associated with PM remain unclear.

MATERIAL AND METHODS

We mined data collected as part of our clinical comprehensive genomic profiling (CGP) initiative which has to date analyzed 8 PM (&gt;50% papillary morphology) and 22 meningiomas with focal papillary features (10–50%) amongst over 500 additional meningiomas of other subtypes. The samples were analyzed in a CAP/CLIA-accredited laboratory (Foundation Medicine, Cambridge, MA). GCP was performed on hybridization-captured, adaptor ligation-based libraries to a mean coverage depth of &gt;650x for 236 or 315 genes plus the introns from 19 or 28 genes frequently involved in cancer.

RESULTS

In our cohort of 8 PMs, we identified three cases with inactivation of PBRM1; two cases with a truncating mutation in PBRM1 and one with homozygous deletion of PBRM1. Of the 22 meningiomas with only focal papillary features, 8 cases were PBRM1-mutant. Thus, 11 of 30 cases (36.7%) with at least focal (&gt;10%) papillary morphology had inactivation of PBRM1.In the entire cohort of 562 meningiomas, we identified five additional cases with inactivating alterations in PBRM1 that did not display overt papillary morphology in the H&E sections available for analysis. Thus, 11 of 16 PBRM1-mutant cases (69%) occurred in meningioma with papillary histologic features as opposed to 19 of 546 wild-type cases (3.5%), supporting a significant association between papillary features and PBRM1 mutation (p&lt;0.0001). The majority of PBRM1-mutant meningiomas occurred in female patients (n=10/16, 62.5%), and median age was 51 years. Most cases were located supratentorially (n=10).

CONCLUSION

We identified the tumor suppressor gene PBRM1 as a recurrently altered gene in meningiomas with papillary histomorphology. Further investigational studies are needed to assess outcomes of PBRM1-mutant meningioma and to determine whether mutation is an independent negative prognostic biomarker.

PATH-40. INTRAGENIC DMD DELETIONS ARE THE MOST COMMON RECURRENT GENOMIC ALTERATIONS IN ESTHESIONEUROBLASTOMA

INTRODUCTION

Esthesioneuroblastoma (ENB) is a rare, malignant neuroectodermal tumor of the olfactory epithelium. To date, a few recurrent genetic alterations have been identified in ENB. Here, we sought to examine the genomic signature on a series of clinically well-characterized aggressive ENB samples.

METHODS

We performed whole-exome sequencing in a cohort of 26 ENB samples from 12 patients, containing 11 matched primary-metastatic samples. Additionally, targeted sequencing was carried out in all samples to determine TERT promoter hotspot mutations. Furthermore, we performed immunohistochemistry (IHC) using an antibody that recognizes the dystrophin central rod domain in all available specimens.

RESULTS

Our cohort consisted of 9 male and 3 female patients with a median age of 66 years at first diagnosis (4- 77 years). One patient was staged Kadish B at the time of diagnosis and eleven were staged Kadish C. The median overall survival was 3.85 years (0.3 – 16 years). Consistent with previous findings, each tumor exhibited a different mutational signature and the mutational landscape appears to be predominantly driven by copy number variations. Interestingly, we detected intragenic deletions in dystrophin (DMD) as the most common and consistent alteration in ENB patients (in 11 of 12 patients, 91.6%). DMD deletions, when identified within the primary ENB, were preserved in all subsequent metastatic lesions. Moreover, DMD deletions where concurrently identified in three cases with multiple metastases. IHC revealed the concurrent loss of dystrophin expression, the protein encoded by DMD, in all cases with DMD deletions. Otherwise, no other recurrent genomic findings were detected, including TERT promoter mutations.

CONCLUSIONS

Our findings validate previously described DMD deletions as the most common recurrent genomic alteration in primary ENB. Furthermore, our data demonstrate that DMD deletions were perpetuated in subsequent metastatic lesions, and when identified in any metastasis, were present in other metastases from the same patient.

Poor prognosis associated with TERT gene alterations in meningioma is independent of the WHO classification: an individual patient data meta-analysis

BACKGROUND

TERT gene alterations (TERT-alt) have been linked to increased risk of recurrence in meningiomas, whereas the association to mortality largely remain incompletely investigated. As incongruence between clinical course and WHO grade exists, reliable biomarkers have been sought.

METHODS

We applied the Preferred Reporting Items for Systematic Review and Meta-Analyses of individual participant data Statement. We compiled data from eight studies and allocated patients to TERT-alt (n=59) or TERT promoter wild-type (TERTp-wt; n=618). We compared the two groups stratified for WHO grades as: incidence rates, survival probabilities and cumulative recurrences. We estimated the effects of WHO grade, age at diagnosis and sex as HRs.

RESULTS

TERT-alt occurred in 4.7%, 7.9% and 15.4% of WHO-I/WHO-II/WHO-III meningiomas, respectively. The median recurrence-free survival was 14 months for all TERT-alt patients versus 101 months for all TERTp-wt patients. The HR for TERT-alt was 3.74 in reference to TERTp-wt. For all TERT-alt patients versus all TERTp-wt patients, the median overall survival was 58 months and 160 months, respectively. The HR for TERT-alt was 2.77 compared with TERTp-wt. TERT-alt affected prognosis independent of WHO grades. Particularly, the recurrence rate was 4.8 times higher in WHO-I/-II TERT-alt patients compared with WHO-III TERTp-wt patients. The mortality rate was 2.7 times higher in the WHO-I and WHO-II TERT-alt patients compared with WHO-III TERTp-wt patients.

CONCLUSIONS

TERT-alt is an important biomarker for significantly higher risk of recurrence and death in meningiomas. TERT-alt should be managed and surveilled aggressively. We propose that TERT-alt analysis should be implemented as a routine diagnostic test in meningioma and integrated into the WHO classification.

TRIAL REGISTRATION NUMBER

PROSPERO: CRD42018110566.

INNV-04. IDH MUTATION PREDICTION IN GLIOMA: A MULTIMODAL APPROACH

OBJECTIVE

Non-invasive and accurate diagnostic techniques to detect isocitrate dehydrogenase (IDH) mutant glioma may have great potential in routine clinical practice. With this in mind, we performed a multimodal diagnostic approach to predict the IDH mutation status in newly diagnosed gliomas using: 2-Hydroxyglutarate (2HG) single-voxel spectroscopy (SVS), IDH-mutant cell-free tumor-derived DNA (tDNA) in the CSF, in addition to 2HG (D- and L- forms) concentration measurement in the CSF.

METHODS

2HG MR spectroscopy was obtained in 18 patients with a newly diagnosed IDH-mutant glioma. The IDH1/2 mutation status was determined using next generation sequencing in the glioma tissue and in the CSF-tDNA (n=55). In addition, in a subset of patients (n=15), 2HG concentrations were measured in the CSF using liquid chromatography-tandem mass spectrometry (LCMS). Ratios of D-and L-2HG were used to evaluate differences in 2HG accumulation in tumors.

RESULTS

IDH mutations were correctly predicted using the 2HG spectroscopy with 93.3% sensitivity (17/18, 95% CI, 85.3–100%) and 100% specificity (18/18, 95% CI, 88.6–100%). The IDH mutation in the CSF-tDNA was successfully detected with 100% specificity (95% CI, 87.6–100%) and 73.3% sensitivity (95% CI, 65.6–88.3%). The range of the IDH mutation variant allele frequency (VAF) in the CSF-tDNA was 1.53- 47.9%. 2HG detection in the CSF revealed higher sensitivity (100%) and specificity (100%) in a small subset of patients (n = 7). The D-2HG/L-2HG ratios in IDH-mutant cases varied between 1.2 – 13.8, compared with 0.1 – 0.5 in IDH wild-type gliomas.

CONCLUSION

Our findings suggest that 2HG spectroscopy and 2HG detection in the CSF are two reliable methods in IDH mutation prediction in gliomas. On the other hand, the sensitivity of genomic IDH mutation detection in the CSF-tDNA was lower when compared with 2HG detection. Further studies are needed to complement the findings of our exploratory analysis.

RARE-04. TARGETED TREATMENT OF PAPILLARY CRANIOPHARYNGIOMAS HARBORING BRAFV600E MUTATIONS

Craniopharyngiomas are surgically challenging brain tumors. Postoperatively, quality of life is often significantly impaired due to neurological and endocrinological complications. Currently, FDA approved systemic treatments are not available for patients in whom craniopharyngiomas recur after surgery and radiation. Papillary craniopharyngiomas are characterized by the presence of BRAFV600E mutations. To date, five case reports have been published on the treatment of BRAFV600E mutant papillary craniopharyngiomas with BRAF and/or MEK inhibitors. In this presentation, authors from all five previously published reports share their collective experience and provide updated follow-up on their patients, thus generating an overview of all currently available information on targeted therapy in patients with BRAFV600E mutant papillary craniopharyngiomas. We have also included information on an additional patient with a papillary craniopharyngioma recently treated with BRAF and MEK inhibitors after tumor biopsy alone, in the absence of recurrence, highlighting the potential for a neo-adjuvant therapeutic approach. All six cases in our series showed dramatic responses to targeted treatment with BRAF (and MEK) inhibitors. Collectively, our cases are highly promising and informative for patient treatment, although uncertainty remains with regards to the optimal timing, the specific agents (single agent or dual therapy) to be used and the duration of treatment. The ongoing multicenter phase II Alliance A071601 trial (NCT03224767) of vemurafenib and cobimetinib for patients with biopsy-proven residual or recurrent papillary craniopharyngiomas should provide additional information to help guide patient management.

Impact of waiting time after surgery and overall time of postoperative radiochemotherapy on treatment outcome in glioblastoma multiforme

Background

A time factor of radiooncological treatment has been demonstrated for several tumours, most prominently for head and neck squamous cell carcinoma and lung cancer. In glioblastoma multiforme studies of the impact of postoperative waiting times before initiation of radio- or radiochemotherapy were inconclusive. Moreover analysis of the impact of overall treatment time of radiochemotherapy as well as overall duration of local treatment from surgery to the end of radiochemotherapy is lacking to date.

Methods

In this retrospective cohort study, we included 369 consecutive patients treated at our institution between 2001 and 2014. Inclusion criteria were histologically proven glioblastoma multiforme, age ≥ 18 years, ECOG performance status 0–2 before radiotherapy, radiotherapy or radiochemotherapy with 33 × 1.8 Gy to 59.4 Gy or with 30 × 2.0 Gy to 60 Gy. The impact of postoperative waiting time, radiation treatment time and overall duration of local treatment from surgery to the end of radiotherapy on overall (OS) and progression-free (PFS) survival were evaluated under consideration of known prognostic factors by univariate Log-rank tests and multivariate Cox-regression analysis.

Results

The majority of patients had received simultaneous and further adjuvant chemotherapy, mainly with temozolomide. Median survival time and 2-year OS were 18.0 months and 38.9 % after radiochemotherapy compared to 12.7 months and 12.6 % after radiotherapy alone. Median progression-free survival time was 7.5 months and PFS at 2 years was 14.3 % compared to 6.0 months and 3.3 %, respectively. Significant prognostic factors in multivariate analysis were age, resection status and application of simultaneous chemotherapy. No effect of the interval between surgery and adjuvant radiotherapy (median 27, range 11–112 days), radiation treatment time (median 45, range 40–71 days) and of overall time from surgery until the end of radiotherapy (median 54, range 71–154 days) on overall and progression-free survival was evident.

Conclusion

Our data do not indicate a relevant time factor in the treatment of glioblastoma multiforme in a large contemporary single-centre cohort. Although this study was limited by its retrospective nature, its results indicate that short delays of postoperative radiochemotherapy, e.g. for screening of a patient for a clinical trial, may be uncritical.

Anticoagulation management of myocardial infarction after deep brain stimulation: a comparison of two cases

Deep brain stimulation (DBS) is an established treatment of various diseases, particularly used for idiopathic Parkinson's disease. Frequently, DBS patients are multimorbid and managing them may be challenging, since postoperative complications can become more likely with age. In this article, we present two cases of myocardial infarction after DBS with different therapeutic strategies. Case 1 was anticoagulated with a heparin infusion with a target partial thromboplastine time (PTT) between 50 and 60 s after the myocardial infarction and showed 3 days later, after an initial postoperative inconspicuous cranial computer tomography, an intracerebral haematoma, which was evacuated without explanting the DBS lead. Case 2 was only treated with enoxaparine 40 mg s.c. twice a day after the myocardial infarction without any further complications. Both cases benefited from the DBS with respect to the motor fluctuations, but case 1 continued to suffer from psychomotor slowdown, mild hemiparesis of the left side, visual neglect and a gaze paresis. Unfortunately, there are no established guidelines or therapy recommendations for the management of such patients. An individual therapy regime is necessary for this patient population regarding the bleeding risk, the cardial risk and the symptoms of the patient. Retrospectively, the rejection of the intravenous application of heparin in case 2 seems to be the right decision. But regarding the small number of cases, it remains still an individual therapy. Further experience will help us to develop optimal therapy strategies for this patient population.

The prostate stem cell antigen represents a novel glioma-associated antigen

Gliomas of WHO grades III-IV are malignant brain tumors mostly resistant to conventional therapies. Therefore, novel strategies for the treatment of gliomas are warranted. Although immunotherapy is gaining increased attention for the treatment of malignant gliomas and in particular of glioblastoma multiforme (GBM), this approach requires the identification of appropriate antigens. Our aim was to investigate the expression of the prostate stem cell antigen (PSCA), a highly N-glycosylated phosphatidylinositol (GPI)-anchored cell surface protein, in gliomas of different WHO grades in order to evaluate its potential as a diagnostic marker and as a target for immunotherapy. Tumor specimens and controls were assessed by quantitative RT-PCR, Western blotting and immunohistochemistry. The samples investigated in the study consisted of 210 human glial tumors, among which 31 were oligodendrogliomas, 9 ependymomas and 170 were astrocytomas (including 134 glioblastomas). PSCA was absent in normal brain tissue, but was detected in WHO grade III-IV gliomas. Weak PSCA protein expression was also recognized in some WHO grade I and WHO grade II tumors. The difference between WHO grade I-II tumors and WHO grade III-IV tumors was statistically significant (p<0.001). Our results suggest that increased PSCA expression levels are linked to gliomas of WHO grades III and IV, and may represent a suitable additional target for immunotherapy of gliomas.