Δευτέρα 5 Σεπτεμβρίου 2022

P11.52.A Peripheral neuropathies after BRAF and/or MEK inhibitors treatment: a pharmacovigilance study

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Abstract
Background
BRAF (BRAFi) and MEK inhibitors (MEKi) demonstrated significant efficacy in the treatment of BRAF-activated tumours, firstly melanoma. Nevertheless, they are not devoid of adverse events. Sparse reports in the literature suggest the potential occurrence of peripheral neuropathies (PN) under BRAFi/MEKi treatment, but their characteristics remain poorly defined. We aimed to characterize the clinical phenotypes of PN occurring under BRAFi/MEKi treatment using a national pharmacovigilance database.
Material and Methods
We queried the French pharmacovigilance database for all cases of PN toxicity attributed to at least one BRAFi or MEKi compound. Only cases with a least symptoms description and nerve conduction studies (NCS) conclusion were included.
Results
Sixteen cases of PN occurred in 15 patients were identified. All patients had underlying melanoma. Two main phenotypes were seen. Six patients (dabrafenib-tr ametinib, n=3; vemurafenib, n=2; vemurafenib-cobimetinib, n=1) presented a length-dependent axonal polyneuropathy: symptoms were mostly sensory at lower limbs; NCS disclosed an axonal neuropathy; management and outcome were variable. Nine patients (dabrafenib-trametinib, n=5, encorafenib-binimetinib, n=3, and vemurafenib-cobimetinib, n=1) developed a demyelinating polyradiculoneuropathy: symptoms affected the four limbs and included hypoesthesia, weakness, and ataxia; cranial nerves were involved in four; NCS showed predominantly demyelinating features; most patients received intravenous immunoglobulins (n=6) or glucocorticoids (n=5), but the outcome was variable; one patient was rechallenged with a different BRAFi/MEKi with a rapid relapse.
Conclusion
Patients under treatment with BRAFi/MEKi may develop treatment-induced PN. Two main phenotypes are seen: a symmetric, axonal, length-dependent polyneuropathy, and a demyelinating polyradiculoneuropathy.
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P12.13.B Investigating the tumor - immune cell crosstalk inex vivo glioblastoma models

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Abstract
Background
Immunotherapy is a promising therapeutic approach to fight cancer by activating the immune system. Multiple immune-based strategies are under development that aim at recruiting or re-activating cellular components of the immune system. While immunotherapies have recently revolutionized cancer therapy, they have shown so far little therapeutic success in glioblastoma patients. To enhance the efficacy of novel strategies, we need to better understand the immunogenic status of glioblastoma cells and their cross-talk with immune cells in different microenvironmental niches.
Material and Methods
We assessed expression of molecules related to antigen processing and presentation as well as immune checkpoints in patient tumor databases as well as in a series of glioblastoma patient-derived organoids, 3D stem-like cultures and adherent cell lines under varying microenvironmental conditions (varying oxygen levels, inflammation ). We further established an allogenic co-culture protocol for glioblastoma organoids with immune cells isolated from HLA matched donor blood, allowing for the functional assessment of the crosstalk between tumor and immune cells.
Results
Analysis of a large cohort of patient tumors and patient-derived glioblastoma preclinical models shows inter-patient heterogeneity at the level of components of major histocompatibility complex (MHC)-MHC-II, immune checkpoints. Glioblastoma cells in general express MHC-I machinery, albeit at different levels. MHC-II and immune checkpoints are variably expressed across glioblastoma cells. Different tumor microenvironment conditions, including hypoxia and interferon-γ, impact the expression of immune-related molecules. Upon co-culture, HLA-matched donor-derived T cells integrate well into the core of glioblastoma tumor organoids and display reciprocal crosstalk with tumor cells.
Conclusion
Assessing antigen presentation and immune cell responses at the functional level are key to improve patient-specific responses to immunotherapies. Advanced glioblastoma organoids incorporating the immune compartment appear as clinically-relevant models for ex vivo efficacy studies.
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P12.10.A Supratentorial glioblastoma with spinal metastasis: a case report with molecular profiling

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Abstract
Background
Glioblastoma (GBM) is regarded as an aggressive brain tumor that rarely develops extracranial metastases. Despite well-investigated molecular alterations in GBM, there is a limited understanding of these associated with the metastatic potential of GBM.
Material and Methods
We present a case report of a 43-year-old woman with frontal GBM IDH-wildtype, who underwent gross-total resection followed by chemoradiation. Five months after surgery, the patient was diagnosed with an intraspinal GBM metastasis. Next-generation sequencing analysis of both primary and metastatic GBM tissues was performed using the Illumina TruSight Tumor 170 assay.
Results
The number of single nucleotide variants observed in the metastatic sample was more than 2-times higher. Mutations in TP53, PTEN, and RB1 found in the primary and metastatic tissue samples are indicative of the mesenchymal GBM subtype. Among others, in the metastatic s ample, there were detected two inactivating mutations (Arg1026Ile, Trp1831Ter) in the NF1 gene, two novel NOTCH3 variants of unknown significance predicted to be damaging (Pro1505Thr, Cys1099Tyr), one novel ARID1A variant of unknown significance (Arg1046Ser), and one gene fusion of unknown significance EIF2B5-KIF5B.
Conclusion
Based on the literature evidence, the inactivation of NF1, NOTCH3, and ARID1A could explain, at least in part, the acquired invasiveness and metastatic potential in this particular GBM case.This work was supported by the grant MUNI/A/1408/2021 of the Masaryk University, Brno, Czech Republic, and INTER-EXCELLENCE Programme / INTER-COST project no. LTC20027 of the Ministry of Health, Czech Republic.
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P11.75.B Survival benefit of radiotherapy and surgery in patients with lung cancer brain metastases with poor prognosis factors

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Abstract
Background
Radiotherapy and surgery are the standard treatments for lung cancer brain metastases (BMs). However, limitted studies focused on the treatments for patients with lung cancer BMs with poor prognosis factors. The purpose of this study was to investigate the effects of radiotherapy and surgery in patients with lung cancer BMs with poor prognosis factors, providing reference for clinical strategies.
Material and Methods
We analyzed retrospectively 714 patients with lung cancer BMs. A 1:1 propensity score matching (PSM) was performed to balance potential confounders. Analyses of overall survival (OS) and risk factors for OS were assessed by log-rank test and Cox proportional hazard model.
Results
Age ≥65 years, Karnofsky Performance Scale (KPS) score ≤70, anaplastic large-cell lymphoma kinase (ALK)/epidermal growth factor receptor (EGFR) wild type, extracranial metastases, non-surgery and non-radiotherapy le d to poor prognosis. Patients were stratified according to these factors. Radiotherapy and surgery showed no survival benefit in patients with aged ≥65 years or pretreatment KPS score ≤70 before and after PSM. Before PSM, whole brain radiotherapy (WBRT) improved the OS and predicted good prognosis in patients with ALK/EGFR wild type or extracranial metastases. WBRT also predicted good prognosis in patients with non-surgery. Stereotactic radiosurgery (SRS) improved the OS and predicted good prognosis in patients with ALK/EGFR wild type or non-surgery. WBRT plus SRS improved the OS and predicted good prognosis in patients with extracranial metastases or non-surgery. WBRT plus SRS also predicted good prognosis in patients with ALK/EGFR wild type. Surgery improved the OS and predicted good prognosis in patients with non-radiotherapy. After PSM, SRS improved the OS and predicted good prognosis in patients with non-surgery. WBRT plus SRS improved the OS and predicted good prognosis in patients with non-surgery or extracranial metastases. WBRT plus SRS also predicted good prognosis in patients with ALK/EGFR wild type. Surgery improved the OS of patients with non-radiotherapy. We defined that the treatment would provide significant survival benefit if it both prolonged the OS and predicted good prognosis. Meanwhile, the results after PSM were more convincing than the results before PSM.
Conclusion
Radiotherapy has significant survival benefit in patients with lung cancer BMs with poor prognosis factors, including patients with ALK/EGFR wild type or extracranial metastases or non-surgery. Surgery only has significant survival benefit in patients with non-radiotherapy.
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P02.01.B The telomere maintenance mechanism spectrum and its dynamics in gliomas

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Abstract
The activation of the telomere maintenance mechanism (TMM) is one of the critical drivers of cancer cell immortality. In gliomas, TERT expression and TERT promoter mutation are considered to reliably indicate telomerase activation, while ATRX mutation indicates alternative lengthening of telomeres (ALT). However, these relationships have not been extensively validated in tumor tissues. Here, we show through the direct measurement of telomerase activity and ALT in a large set of glioma samples that the TMM in glioma cannot be defined in the dichotomy of telomerase activity and ALT, regardless of TERT expression, TERT promoter mutation and ATRX mutation. Moreover, we observed that a considerable proportion of gli omas lack both telomerase activity and ALT (Neither group). And this Neither group exhibited evidence of slow growth potential. From a set of longitudinal samples from a separate cohort of glioma patients, we discovered that the TMM is not fixed but changes with glioma progression. Collectively, these results suggest that the TMM is a dynamic entity and that reflects the plasticity of the oncogenic biological status of tumor cells and that the TMM should be defined by the direct measurement of telomerase enzyme activity and evidence of ALT.
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P11.74.A Plexiform Neurofibromas prevalence and treatment modalities in a referral comprehensive cancer center

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Abstract
Background
Neurofibromatosis type 1 (NF1) is the most common tumor predisposition syndrome, with an incidence of 1/3500. Plexiform neurofibromas (PN) are benign tumors that can occur along the nerve sheath throughout the body, with unpredictable growth and with risk of malignant transformation. Symptoms will depend on their size and location, and include pain, deformity and functional impairment. There is a great variability in the PN severity and impact on quality-of-life (QOL). An unknown percentage of NF1 patients may need treatment, either medical and/or surgical.
Objectives
To assess the frequency of PN in a NF1 population followed in a comprehensive cancer center.
Material and Methods
Retrospective study. All patients with NF1 and PN followed in our center, between 31/12/2000 and 31/12/2021.
Results
Of 438 NF1 patients, 185 had PN (42%). 52 NF1 patients with PN were children (≤ 18). The most common sym ptoms were pain in 71 people (38,4%), deformity in 70 (37,8%) and functional impairment in 69 (37,3%). Several patients had a combination of these symptoms. Different treatment modalities were used for PN: medical, surgical or both. In this study, 54 patients (29,1%) were treated with MEK inhibitors (selumetinib), 74 patients (40%) were treated surgically and 12,4% (23) needed a combined approach (medical and surgical treatment).
Conclusion
PN are frequent in NF1 patients. A significant percentage is symptomatic and will require treatment, surgical, medical or both. There is no standard of care for PN NF1. The timing and sequence of medical and surgical treatment is yet to be defined.
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P11.73.B The diagnostic value of frame-based stereotactic biopsies in the age of precision oncology: A cross-sectional study

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Abstract
Background
For non-resectable, eloquent, multifocal and deep-seated intracranial lesions, stereotactic frame-based biopsies can deliver a finite amount of tissue for neuropathology studies. With the increasing role of molecular genetics in the diagnostics of intracranial tumors, sufficient tissue for sequencing studies is of paramount importance. This study explored the rate of successful diagnosis after stereotactic frame-based biopsies of intracranial lesions in a high-throughput neurooncology center
Material and Methods
145 consecutive patients undergoing frame-based stereotactic biopsies in 2020 and 2021 at our neurosurgical department were included in this retrospective analysis. Aspects of histological and molecular (methylomics, panel-sequencing) neuropathology analysis in addition to clinical and radiological variables were analyzed. Cases were classified as conclusive, likely-conclusive (sufficient diagnosis with non-s atisfying sequencing information), and inconclusive neuropathological diagnosis.
Results
Of 145 cases analyzed, astrocytic tumors were suspected in n= 94 (67%) of patients. In n= 122 cases (84%), a conclusive diagnosis was possible. For 14 (11%) cases, a likely-conclusive diagnosis was established Diagnoses comprised mainly WHO 4 glioblastomas (56%), WHO 3 gliomas (2%) in addition to WHO 1 and 2 gliomas (n=7, 5%), CNS lymphomas (n=23, 16%), inflammatory diseases (n=10, 7%) and normal or reactive tissue (n=4, 3%). Methylomics were pivotal in providing an integrated diagnosis in 30% of the cases (panel sequencing in 14%). In n= 12 (8%) of the cases further testing was hindered by insufficient tissue sample DNA. Only in 3 out of 12 cases this resulted in a final inconclusive diagnosis.
Conclusion
Although stereotactic frame-based biopsies deliver a limited amount of tissue, they bear an excellent histopathological and molecular genetic diagnostic yield, with rare case s of missing molecular data or rarely insufficient diagnosis. Optimizing the number and representativeness of cell and DNA-rich stereotactic biopsy specimen might enhance the diagnostic and therapeutic potential of precision oncology even further.
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P11.71.B Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) in a patient with blastic plasmacytoid dendritic cell neoplasm: a rare neurologic manifestation in a rare disease

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Abstract
Background
Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare aggressive myeloid hematological malignancy. Skin lesions, bone marrow, lymph nodes or visceral organs can be involved. 30% of patients will have infiltration to the nervous system,occult asymptomatic infiltration is frequent. Immunophenotype express CD4, CD56, and CD123, and flow cytometry is essential.
Material and Methods
70-yo Hispanic male with a 1-month history of multiple violaceous cutaneous nodules and adenopathies.Neurological complaints included diplopia, hypoesthesia in the left face, dysphagia, gait difficulties, and generalized weakness with distal hypoesthesia. Examination revealed multiple cranial neuropathy (bilateral VI and VII nerve palsies, left V3 and VIII palsies and IX, X involvement), global areflexia, length-dependent weakness, ataxic gait and cerebellar syndrome. An inguinal ganglionar biopsy retrieved cells positive for CD4, TCL 1, CD68 and CD123, whereas CD3, CD20, CD7, CD8, CD30 and myeloperoxidase were negative. PET/CT showed multiple supra and infradiaphragmatic adenopathies, bilateral pleural, pericardial and abdominal implants. Bone marrow biopsy was negative. Brain MRI showed contrast enhancement in the cerebellar folia and in the roots of the cranial nerves clinically involved. Multiple CSFs demonstrated high protein count (281- 310mg/dl), normal glucose and cell count; CSF flow cytometry and cytology reported no blastic infiltration (negative CD4, CD56 and CD123), CSF onconeuronal antibodies were negative. Nerve conduction studies fulfilled definite electrodiagnostic EFNS criteria for CIDP. Sural nerve biopsy reported inflammatory demyelination without infiltration. Systemic chemotherapy (Cyclophosphamide/Vincristine) with intrathecal cytarbine/methotrexate was administered.
Results
Favorable initial, but brief response was noticed for the cranial nerves and gait. He had neurological relap se with gait impossibility. Neuraxis MRI showed no contrast enhancement in the brain but new contrast enhancement of lumbosacral roots. Nerve conduction studies reported severe worsening criteria of CIDP. The PET/CT demonstrated complete response. Five days of methylprednisolone (1gr IV) followed by oral prednisone were prescribed (50 mg qd). However, two weeks later he suffered clinical neurological worsening with respiratory failure. IVIg was started (.4g/kg/day for 5 days) with no improvement; palliative care decision was consented.
Conclusion
We report the case of an adult male with multiple cranial nerve palsy, cerebellar syndrome and refractory rapidly progressive asymmetric polyneuropathy with BPDCN. CIDP in the absence of multiple attempts to demonstrate nervous system infiltration led us to consider this as a paraneoplastic phenomenon refractory to treatment. To our knowledge no CIDP has been reported in this rare disease
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P17.11.A Experience of ketogenic diet with support of liquid formula 3:1 and high-grade gliomas: Case series

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Abstract
Background
High-grade gliomas, including glioblastoma, are the most common primary malignant brain tumors in adults. Despite the efforts to develop new therapies, treatment options remain limited and the prognosis is poor. Ketogenic diet, is an emerging complementary therapy for high-grade gliomas. It is hypothesized that through the change of the energy source from glucose to ketones and the inability of glioma cells to metabolize ketone bodies with the same ease due to inefficient oxidative phosphorylation, tumor growth is slowed. The feasibility of a ketogenic diet is a matter of concern. Its influence on the quality of life of patients with advanced cancers showing that even though it may cause constipation and reflux, quality of life is generally not affected
Material and Methods
We reported a case series of patients with high-grade gliomas using ketogenic diet with liquid formula 3:1 ratio (KDS) as a complementary treatme nt. We describe baseline characteristics, and EORTC-QLQ30 score and symptom evaluation
Results
We describe the case of 3 patients (2 women and 1 man) with diagnoses of grade 4 glioblastoma (2) and grade 3 oligodendroglioma (1), mean age 46.7 years (38- 56 years), ECOG 1 (2) and ECOG2 (1), gross tumor resection (1 glioblastoma patient), subtotal resection (1 glioblastoma patient), and biopsy (1 oligodendroglioma patient). All patients received radiotherapy, 66.7% (n=2) stupp protocol, and 33.3% (n=1) received hypofractionated therapy and adjuvant treatment with temozolomide. All patients received first line with temozolomide, and 33.3% received a total of four lines of chemotherapy. All the patients were fed orally and managed with KDS at the last progression. Median follow up time was 4 months. KDS didn't impact corporal weight and a positive impact was noted in seizure episodes (> 3 per day before vs < 3 per day after DKS) and quality of life (EORTC-QLQ30 61,3 [60 - 66,8] at the begining vs 70,9 [69,8 - 71,2] at the last visit). Regarding tolerance, one patient presented diarrhea and/or constipation grade 1 the first 5 days of treatment. Compliance was measured by days with a median adherence of 90%. Current disease status is stable disease (RANO criteria) in the three patients.
Conclusion
KDS could be an interesting therapy complementary to standard treatment in patients with high grade gliomas, especially in those patients who debut with seizures, improving quality of life and number of convulsive crises. More studies in adult patients are required to confirm this hypothesis
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P17.09.A Regorafenib and Re-irradiation: analysis of clinical outcomes and toxicities in patients with recurrent glioblastomas

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Abstract
Background
Glioblastoma is the most common and aggressive primary brain tumor in adults.The aggressiveness and poor prognosis related to this disease join to the limited available treatment options. The current standard of care involves surgical resection followed by concomitant radiotherapy and chemotherapy. At recurrence, no standard treatment exists and there are no guidelines to facilitate decisions in the recurrent setting. Available options include re-operation, re-irradiation, systemic therapy, alone or in combination. In recent years, immunotherapy strategies have revolutionized the treatment of many cancers, increasing the hope for GBM therapy. Regorafenib (Stivarga) is an inhibitor of several kinases involved in the mechanisms that regulate neoangiogenesis processes, through the inhibition vascular endothelial growth factor (VEGF) receptors and the modifications of the tumor microenvironment; specifically, Regorafenib binds an d stabilizes PSAT1 (phosphoserine aminotransferase 1). The dual regulatory mechanism underlying PSAT1-induced autophagy arrest accounts for the superior anti-GBM effect of Regorafenib compared with Temozolomide.
Material and Methods
15 patients with documented disease progression after surgery followed by RT and TMZ were assigned to receive regorafenib (REG) 160 mg once daily for the first 3 weeks of each 4-week cycle. All patients received prior radiation therapy (RT) to a median dose of 60 Gy (range 40.05 -60). Median time to retreatment after prior RT was 16 months (range 14-33). Tumor volumes ranged from 81.7 cm3 to 422.4 cm3 (CTV) and from 112.7 cm3 to 422.4 cm3 (PTV).3 patients (20%) received concomitant reirradiation with a radiation dose of 37.5 Gy in 15 fractions of 2.5 Gy.
Results
the median follow-up was 9.5 months (range 5-22). The overall survival and the progression-free survival rates were 53,8 %, and 46,6 % respectively at 2 years. In 53% the sympto ms were stable. Only one patient developed late toxicity: acute pancreatitis (Grade I) regressed on interruption of Regorafenib. No other neurological deficits occurred during follow-up. At last follow up 60% of patients were alive.
Conclusion
we report our experience with Regorafenib, administered in patients with rapid progression after the end of postoperative radio chemotherapy treatment. Regorafenib might be a new potential treatment option for recurrent glioblastoma: it was well tolerated also in cases of combined treatment with reirradiation and appeared effective. Other studies will be necessary to evaluate and confirm the role of Regorafenib in glioblastoma patients and the potential effectiveness of the combined therapeutic strategy: Regorafenib-reirradiation.
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