Prognosis of glioblastoma patients improves significantly over time interrogating historical controls

BACKGROUND

Glioblastoma (GBM) is the most common devastating primary brain cancer in adults. In our clinical practice, median overall survival (mOS) of GBM patients seems increasing over time.

METHODS

To address this observation, we have retrospectively analyzed the prognosis of 722 newly diagnosed GBM patients, aged below 70, in good clinical conditions (i.e. Karnofsky Performance Status -KPS- above 70%) and treated in our department according to the standard of care (SOC) between 2005 and 2018. Patients were divided into two groups according to the year of diagnosis (group 1: from 2005 to 2012; group 2: from 2013 to 2018).

RESULTS

Characteristics of patients and tumors of both groups were very similar regarding confounding factors (age, KPS, MGMT promoter methylation status and treatments). Follow-up time was fixed at 24 months to ensure comparable survival times between both groups. Group 1 patients had a mOS of 19 months ([17.3-21.3]) while mOS of group 2 patients was not reached. The recent period of diagnosis was significantly associated with a longer mOS in univariate analysis (HR=0.64, 95% CI [0.51 - 0.81]), p < 0.001). Multivariate Cox analysis showed that the period of diagnosis remained significantly prognostic after adjustment on confounding factors (adjusted Hazard Ratio (aHR) 0.49, 95% CI [0.36-0.67], p < 0.001).

CONCLUSION

This increase of mOS over time in newly diagnosed GBM patients could be explained by better management of potentially associated non-neurological diseases, optimization of validated SOC, better management of treatments side effects, supportive care and participation in clinical trials.

Epileptic seizures in patients with primary central nervous system lymphoma: A systematic review

BACKGROUND

Primary central nervous system lymphoma (PCNSL) accounts for less than 5% of primary brain tumors. Epileptic seizures are a common manifestation of brain tumors; however, literature on the prevalence, characteristics, and oncological implications of seizures in patients with PCNSL is limited, and the management of antiepileptic drugs (AEDs) is unclear. This review aimed to summarize the existing knowledge on seizures in PCNSL, their potential association with surgery, oncological treatment, survival rates, and management of AEDs.

METHODS

A systematic review was performed according to the PRISMA recommendations and included articles published between 1953 and 2023 describing seizures in patients with PCNSL.

RESULTS

The search identified 282 studies, of which 21 were included. Up to 33% of patients with PCNSL developed seizures, mostly at the initial presentation. Little information was found on changes in seizure incidence through the course of the disease, and no details were found on seizure frequency, the percentage of treatment-resistant patients, or the evolution of seizures at remission. Younger age, cortical location, and immunodeficiency have been identified as potential risk factors for seizures, but evidence is very limited. The growing use of vigorous treatments including intensive chemotherapy with autologous stem cell transplantation and immunotherapy with CAR-T cells is associated with a higher incidence of seizures. The association between seizure development and patient mortality in PCNSL remains unknown. There are no data on AED prophylaxis or the use of specific AEDs in PCNSL.

CONCLUSIONS

Further studies are needed to investigate seizures in larger cohorts of PCNSL, to clarify their prevalence, better characterize them, identify risk factors, analyze survival rates, and make recommendations on AED management. We recommend following general practice guidelines for seizures symptomatic of brain tumors and not to prescribe AED prophylaxis in PCNSL.

Recent advances in the diagnosis and the treatment of primary CNS lymphoma

This review focuses on the recent progress in the management of primary central nervous system lymphoma (PCNSL). Multiomic analyses allowed to better understand the tumorigenesis of PCNSL and to establish a molecular classification with prognostic value that will optimize patient management and guide future targeted approaches. Cooperative clinical trials have demonstrated the feasibility and efficacy, in selected fit patients, of high-dose chemotherapy with autologous stem cell transplantation as post-induction consolidation, that will progressively replace whole brain radiotherapy associated with a much higher risk of delayed neurotoxicity. Several novel treatments have shown efficacy and overall good tolerance in PCNSL patients, such as Bruton's tyrosine kinase (BTK) inhibitors, imids, immune checkpoint inhibitors and chimeric antigen receptor T-cells (CAR-T). This opens promising therapeutic perspectives to improve the current standard treatment, especially for elderly and unfit patients who represent a growing population.

Systemic relapses of primary CNS lymphomas (PCNSL): a LOC network study

Primary central nervous system lymphomas (PCNSLs) classically remain confined within the CNS throughout their evolution for unknown reasons. Our objective was to analyse the rare extracerebral relapses of PCNSL in a nationwide population-based study. We retrospectively selected PCNSL patients who experienced extracerebral relapse during their follow-up from the French LOC database. Of the 1968 PCNSL included in the database from 2011, 30 (1.5%, median age 71 years, median KPS 70) presented an extracerebral relapse, either pure (n = 20) or mixed (both extracerebral and in the CNS) (n = 10), with a histological confirmation in 20 cases. The median delay between initial diagnosis and systemic relapse was 15.5 months [2-121 months]. We found visceral (n = 23, 77%), including testis in 5 (28%) men and breast in 3 (27%) women, lymph node (n = 12, 40%), and peripheral nervous system (PNS) (n = 7, 23%) involvement. Twenty-seven patients were treated with chemotherapy, either with only systemic targets (n = 7) or mixed systemic and CNS targets (n = 20), 4 were consolidated by HCT-ASCT. After systemic relapse, the median progression-free survival and overall survival (OS) were 7 and 12 months, respectively. KPS > 70 and pure systemic relapses were significantly associated with higher OS. Extracerebral PCNSL relapses are rare, mainly extranodal, and frequently involve the testis, breast, and PNS. The prognosis was worse in mixed relapses. Early relapses raise the question of misdiagnosed occult extracerebral lymphoma at diagnostic workup that should systematically include a PET-CT. Paired tumour analysis at diagnosis/relapse would provide a better understanding of the underlying molecular mechanisms.

CSF biomarkers in primary CNS lymphoma

PCNSL is a non-Hodgkin lymphoma (NHL) affecting brain, spinal cord, eyes and leptomeninges. In the past two decades, its prognosis significantly improved due to therapeutic advances but it remains a highly aggressive tumor and early diagnosis is necessary for optimal management. Diagnosis relies on the identification of lymphoma cells in brain tissue obtained by stereotactic biopsy. Alternatively, lymphoma cells may be found in CSF through lumbar puncture (LP) or by a vitrectomy. For several reasons, the diagnosis of PCNSL may be challenging. Misleading radiological presentations are frequent. Dramatic response to steroids may bias histological analysis and deep brain location or frail health status can contraindicate brain biopsy. In the follow-up of patients who have been previously treated, differential diagnosis between tumor relapse and post-treatment may be also difficult. Therefore, the development of complementary reliable diagnostic tools is needed. This review will summarize several diagnostic or prognostic CSF biomarkers which have been proposed in PCNSL, their interests and limits.

Molecular and clinical diversity in primary central nervous system lymphoma

BACKGROUND

Primary central nervous system lymphoma (PCNSL) is a rare and distinct entity within diffuse large B-cell lymphoma presenting with variable response rates probably to underlying molecular heterogeneity.

PATIENTS AND METHODS

To identify and characterize PCNSL heterogeneity and facilitate clinical translation, we carried out a comprehensive multi-omic analysis [whole-exome sequencing, RNA sequencing (RNA-seq), methylation sequencing, and clinical features] in a discovery cohort of 147 fresh-frozen (FF) immunocompetent PCNSLs and a validation cohort of formalin-fixed, paraffin-embedded (FFPE) 93 PCNSLs with RNA-seq and clinico-radiological data.

RESULTS

Consensus clustering of multi-omic data uncovered concordant classification of four robust, non-overlapping, prognostically significant clusters (CS). The CS1 and CS2 groups presented an immune-cold hypermethylated profile but a distinct clinical behavior. The 'immune-hot' CS4 group, enriched with mutations increasing the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) and nuclear factor-κB activity, had the most favorable clinical outcome, while the heterogeneous-immune CS3 group had the worse prognosis probably due to its association with meningeal infiltration and enriched HIST1H1E mutations. CS1 was characterized by high Polycomb repressive complex 2 activity and CDKN2A/B loss leading to higher proliferation activity. Integrated analysis on proposed targets suggests potential use of immune checkpoint inhibitors/JAK1 inhibitors for CS4, cyclin D-Cdk4,6 plus phosphoinositide 3-kinase (PI3K) inhibitors for CS1, lenalidomide/demethylating drugs for CS2, and enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) inhibitors for CS3. We developed an algorithm to identify the PCNSL subtypes using RNA-seq data from either FFPE or FF tissue.

CONCLUSIONS

The integration of genome-wide data from multi-omic data revealed four molecular patterns in PCNSL with a distinctive prognostic impact that provides a basis for future clinical stratification and subtype-based targeted interventions.

OS07.1.A A threshold of mitotic activity and post-surgery residual volume are independant prognostic factors in astrocytoma IDH-mutant

Background

The distinction between grade 2 and 3 is instrumental to choose between observational follow-up and adjuvant treatment in resected astrocytoma IDH-mutant. However, criteria of grade 2 versus 3 have not been updated since the WHO 2007 classification. There is no consensus on the method of evaluation of the mitotic activity or a cut-off of mitoses separating grade 2 and grade 3 tumors. The objectives were to evaluate the maximal mitotic activity on a series of resected astrocytoma IDH-mutant and assess its prognostic impact on survival.

Material and Methods

Maximal mitotic activity on consecutive high power fields corresponding to 3 mm2 was examined in 118 lower-grade astrocytoma IDH-mutant. The prognostic value for time-to-treatment (TTT) and overall survival (OS) of mitotic activity and other putative prognostic factors (including age, performance status, pre-surgical tumor volume, plurilobar involvement, post-surgical residual tumor volume, midline involvement) was assessed in tumors with (i) ATRX loss, and (ii) without CDKN2A homozygous deletion, lesional enhancement, histological necrosis nor microvascular proliferation.

Results

Among the 75 (64%) of tumors which had gone through observational follow-up after resection, the maximal mitotic activity, the post-surgical residual volume and the plurilobar involvement were independent prognostic factors of TTT (p &lt; 0.0001). A threshold of mitotic activity for grade 2 was fitted on TTT and OS prognosis. Using this threshold, patients with “grade 2 tumors” had a median TTT of 55 months versus 19 months for “grade 3” (p = 0.0057) and a median OS of 102 months versus 73 months respectively (p = 0.001). Residual volume &lt; 1 cm3 was associated with longer OS (113 months versus 88 months, p = 0.0021).

Conclusion

Mitotic activity and post-surgical residual volume can be combined to evaluate prognosis in resected astrocytoma IDH-mutant and could select the best candidates for observational follow-up.

P11.09.B Chemotherapy is an efficient treatment in primary CNS MALT lymphoma

Background

Mucosae-associated lymphoid tissue (MALT) lymphomas are a rare and still poorly understood form of primary central nervous system lymphoma (PCNSL). The aim of this study was to better describe these tumors and their management, and to better appreciate their long-term prognosis after treatment.

Material and Methods

Adult immunocompetent patients with primary CNS MALT lymphoma (PCNSML) were retrospectively selected from the database on PCNSL of the Pitié-Salpêtrière Hospital. All cases had double-read for pathology.

Results

Eleven PCNSML representing 1.7% of the 662 PCNSL included in the database were selected, There were 9 women and two men, all immunocompetent. Their median age was 56 years (min 29; max 78). The median time from first symptoms to diagnosis was 13 months and the median KPS at diagnosis was 90. Location was dural in 8 cases, suggestive of meningioma in 7 cases and of subdural hematoma in 1 case, and parenchymal in 3 cases. The disease was unifocal/localized in 4 cases and multifocal/diffuse in 7 cases. In 3 cases, it was the second reading that allowed making the diagnosis. In first-line treatment, all patients received chemotherapy (CT): “systemic” CT, i.e usually used in systemic MALT lymphomas, in 7 cases (n=7) and “CNS” CT, i.e usually used in CNS lesions in 4 cases. CT was preceded by surgery in 4 cases. No patient received radiotherapy in first line. According to the IPCG (International PCNSL Collaborative Group) criteria, the overall response rate was 7/11 (64%). At latest news, 5 patients had a persistent contrast enhancement, stable without any treatment since a median of 57 months, raising the question of complete response despite persisting contrast enhancement. No patient developed neurotoxicity except for one of the 2 patients who subsequently received radiotherapy. The median follow-up was 109 months. The median progression-free survival was 78.0 months (95% CI [43.4;NA[) and the 10-year overall survival rate was 90% (95% CI [0.7;1[).

Conclusion

This series confirms the classical clinical and radiological presentation of PCNSML. Compared to the literature where the treatment was based on radiotherapy in almost two thirds of cases, the therapeutic approach presented here appears unconventional. This is the first series demonstrating that chemotherapy is an efficient treatment in PCNSML, with an excellent long-term outcome and the absence of neurotoxicity, and calling into question the relevance of the IPCG criteria for the evaluation of their therapeutic response.

P14.48 Extracerebral relapses of primary CNS lymphoma (PCNSL): a LOC network retrospective study

BACKGROUND

Classically PCNSL remain confined within the CNS throughout their evolution for reasons still unknown (&gt; 80% cerebral relapses). The aim of this study was to describe the characteristics and outcomes of the rare extracerebral relapses of PCNSL.

MATERIAL AND METHODS

This is a multicenter, retrospective study. We included all immunocompetent patients newly diagnosed with diffuse large B-cell PCNSL registered in the national LOC network database since 2010 and followed prospectively, who presented an extracerebral relapse, pure (extracerebral only site) or associated with concomitant CNS relapse (mixed). All had body scan and/or TEP -CT at diagnosis work up.

RESULTS

Of the 1968 PCNSL included in the database, 29 (1.5%) patients presented a systemic relapse [median age 71 years, median KPS 70% at relapse], either pure (n=19) or mixed (n=10), with a histological confirmation in 19 cases (66%). The median delay between initial diagnosis and systemic relapse was 15 months [2–49 months], with 5 very early relapses (&lt;8 months) and 10 late relapses (&gt;21 months). 27 patients had symptoms, 21 related to the location of relapse and 6 with only general symptoms. The localization was thoracic (n=11), abdominal/pelvic (n=14), head/neck (n=6) and limbs (n=9). We found visceral (n=24, 83%), including testis in 5 (28%) men and breast in 3 (27%) women, lymph node (n=12, 41%) and peripheral nervous system (PNS) (n=8, 28%; 4 plexus and 4 extradural roots) involvement. 27 patients were treated with chemotherapy, either with only systemic target (n=8) (R-CHOP alone) or mixed systemic and CNS target (n=19) (R-CHOP-MTX, R-ICE, GEMOX, RDHAC) and consolidated by high-dose chemotherapy with autologous stem cell transplantation (HCT-ASCT) in 4 cases [median age 55 years, median KPS 80%], with 34% of complete response. After systemic relapse, median progression-free survival was 8 months and overall survival (OS) was 9 months, 15 months for pure systemic and 4.5 months for mixed relapses. KPS&gt;70%, pure systemic relapses and complete response were significantly associated with higher OS in univariate analysis.

CONCLUSION

Extracerebral PCNSL relapses are very rare, mainly extranodal and involve a large spectrum of anatomical sites, the most frequent being testis, breast and PNS. Prognosis was worse in case of mixed relapse than in pure systemic relapse that was similar to non PCNSL lymphomas. Very early relapses raise the question of misdiagnosed occult extracerebral lymphoma at diagnostic work up that should include systematically a FDG PET-CT. More studies are needed to refine their treatment and to specify the role of HCT-ASCT. Paired tumor tissues at diagnosis (CNS)/relapse (extracerebral) analysis would provide a better understanding of underlying molecular mechanisms.

P03.04 Primary CNS lymphoma of the corpus callosum: presentation and neurocognitive prognosis. Study of a monocentric cohort of 27 patients

BACKGROUND

The corpus callosum (CC) is frequently involved in primary central nervous system lymphomas (PCNSL). The aim of our study was to describe the impact of these lesions on neurocognition of patients presenting with PCNSL of the CC (PCNSL-CC) and their post-therapeutic evolution.

MATERIAL AND METHODS

This is a retrospective single-center study. Patients newly diagnosed at Pitié Salpêtrière Hospital from (1999–2018) were included in this study according to the following criteria: age &gt;18, immunocompetent patient, pathological confirmation (Diffuse Large B cell lymphoma) and CC as main location of the tumor on MRI. Clinical, neuroradiological and neuropsychological data of the patients were collected. In addition, prognostic factors for the neurocognitive outcome of the patients were investigated.

RESULTS

27 patients were included (median age: 67 years, median KPS: 70). At the time of diagnosis, 74% of patients had cognitive impairment and 59% of patients had balance disorders. The cognitive functions most frequently affected were memory and executive functions. Tumor lesions in the CC had a median maximum diameter of 5 cm with a so called “butterfly pattern” in 92% of cases. All patients received a high dose methotrexate based polychemotherapy, including one with radiation therapy, and 67% of patients achieved a complete remission (CR). Median PFS and OS were 33.3 months and 177.9 months respectively. With a median follow-up of 48 months (range 6–156), despite CR, there were still abnormal values in 17% of patients on overall efficiency, 17–55% of patients on executive function tests, 45–55% of patients on memory tests. No significant impaired values were found for visuo-spatial and language tests. Splenial location and age ≥ 60 years were significantly associated with worse episodic memory scores throughout the follow-up.

CONCLUSION

PCNSL-CC are associated with frequent cognitive dysfunctions, especially memory impairment, which may recover only partially despite CR, that warrant specific rehabilitation. Older age (≥ 60) and splenial location have worse neurocognition outcome.

P14.54 Primary central nervous system lymphoma of the spinal cord: a LOC network cohort study

BACKGROUND

Primary central nervous system lymphoma (PCNSL) mainly affects the brain (&gt;90% of the cases), Very little data can be found in the literature on PCNSL with spinal cord localization.

MATERIAL AND METHODS

We present a retrospective study based on the French LOC network database. We selected adult immunocompetentpatients, with a histological or cytological diagnosis of PCNSL, and a spinal cord localization at initial diagnosis.

RESULTS

Of the 2043 PCNSLof the LOC database newly diagnosed since 2011, 14 patients (9 men, median age 68, median Karnofsky performance status 50%)met the selection criteria. The median diagnostic delay was 82 days (min 15-max 1080) compared to 35 days in primary cerebral lymphomas. At diagnosis, walking was impossible in 7/14 patients and 5/14 had indwelling urinary catheter. On MRI, 100% had enlargement of the spinal cord with homogeneous contrast enhancement in 13/14 cases. Spinal cord lesions were unique in 9/14 patients and multiples in 5/14 patients. CSF IL10 level was increased in 6/7 patients. Brain lesions were found in 9/14 patients, located in the posterior fossa in 5/9 cases. The diagnosis was made either on a brain biopsy (N=6), a spinal cord biopsy or surgery (N=5) or the cytologic analysis of the CSF (N=3).4/5 patients had neurological sequel after spinal cord biopsy or surgery. All the patients were treated by high-dose methotrexate-based chemotherapy, followed by spinal cord irradiation (N=1) or autograft (N=2). There was an overall response rate of 71% (complete response in 8/14). 8/14 patients relapsed, 5 in the brain, 2 in the spinal cord, and 1 both in the spinal cord and in the brain. 2-year PFS and OS were 45% and 64%, respectively. Among the long-term responders, 50% remained in wheel chair, while only 10% could walk normally.

CONCLUSION

Considering the high risk of a spinal cord biopsy,the rarity of the disease, as well as the numerous differential diagnoses, the diagnosis of spinal cord lymphoma is difficult. Searching for other lymphomatous locations or assaying CSF IL10 may be helpful in this disease where delay in diagnosis is often prolonged et can cause irreversible handicap.

MRI features of intra-axial histiocytic brain mass lesions

AIM

To describe MRI features, including diffusion-weighted imaging (DWI), magnetic resonance spectroscopy (MRS), and perfusion-weighted imaging (PWI), of intra-axial tumour-like presentations of four different subtypes of histiocytosis.

MATERIAL AND METHODS

The brain MRI findings of 23 patients with histologically proven histiocytosis were reviewed retrospectively (11 Langerhans cell histiocytosis [LCH], eight Erdheim-Chester disease [ECD], one overlap form LCH/ECD, two Rosai-Dorfman disease [RDD], and one haemophagocytic lymphohistiocytosis [HLH]) with single or multiple enhancing intraparenchymal brain lesions.

RESULTS

Histiocytic brain mass lesions show some similar MRI features including Supra and/or infratentorial and/or paraventricular subcortical well-delineated masses, linear ependymal enhancement along the ventricles and brain stem lesions. Masses always present with mixed hyper- and hypointense signal on T2-weighted imaging (WI). Their enhancement is often homogeneous. Apparent diffusion coefficient (ADC) values are often normal or elevated.

CONCLUSION

The presence of multiple periventricular and subcortical enhancing lesions with mixed signal intensity on T2WI and normal or high ADC values should lead radiologists to consider the diagnosis of histiocytic lesions and search for associated systemic lesions.

OS4.3 Feasibility and benefit of Molecular Profiling to Guide Enrollment of Patients with Recurrent Gliomas in Early Phase Trials

BACKGROUND

Participation of glioma patients in early phase clinical trials has recently shown to be safe, although clinical benefits reported in this population were marginal. We aimed to evaluate whether an enrichment strategy based on molecular profiling associates with improved outcome in gliomas patients participating in early phase trials.

MATERIAL AND METHODS

Records of patients enrolled in early phase trials of cytotoxic therapies, small molecule inhibitors or monoclonal antibodies from 2008 to 2017 were analyzed for clinicopathological characteristics, toxicity, response, median progression-free survival (PFS) and overall survival (OS). The primary objective was to evaluate the feasibility and benefit of using molecular profiling to guide enrollment.

RESULTS

Ninety-one patients were enrolled, of whom 47/91 (51.6%) were molecularly oriented. Molecular targets included IDH1/2 (n=15) and BRAF (11) mutations, FGFR1-3 fusions (n= 10) and mutations (n = 4), mismatch repair deficiency (8), and MDM2 amplification (1). Grade 3/4 adverse events were reported in 9/91 (9.9%) patients. In patients with IDH1/2-wild-type high-grade glioma (n=45), the overall response rate (24.0% [95% CI 11.5–43.4] vs 0.0% [95% CI 0.0–16.1], P=0.027) was significantly higher in molecularly-oriented vs non-molecularly-oriented patients. Updated outcome results, and clinical and molecular factors associated with response, PFS and OS in multivariate analyses will be presented at the conference.

CONCLUSION

Using molecular profiling to guide enrollment in early phase trials is feasible and offers potential benefit to gliomas patients. Further studies are warranted to identify the population most likely to benefit from this approach.

P14.73 Toxicity and outcomes of reduced-dose whole brain radiotherapy as consolidation treatment for patients with CNS lymphoma in real life setting

BACKGROUND

Optimal treatment strategy for newly diagnosed primary PCNSL remains controversial. The high risk of radio-induced late-delayed neurotoxicity in patients who achieve long-term disease control constrains the use of classical consolidation WBRT. So as to reduce side cognitive effects, Morris et al, reported a phase II study, to assess the efficacy and toxicity of consolidation reduced-dose (23.4Gy) WBRT (rdWBRT) for patients with complete response after high dose methotrexate based chemotherapy. The study reported a 2-year PFS rate for these patients of 77%, with no evidence of significant cognitive decline during the follow-up (FU) period. The aim of this retrospective study was to report toxicity and outcomes of rdWBRT, in patients < 60 years old with complete response (CR) after HD-MTX based chemotherapy, in real life setting, without selection bias.

MATERIAL AND METHODS

Patients were selected from the French LOC network database, a nationwide database centralizing since 2011 information from 28 different centers in France, representing the main centers involved in PCNSL management. Patients were retrospectively selected according to the following criteria: 1) Pathological diagnosis of diffuse large B cell PCNSL; 2) age>18 and <60 years; 3) immunocompetent status; 4) First line induction treatment based on high dose MTX (At least MTX>1.5 g/m2); 5) CR according to the IPCG criteria after first-line induction treatment. Patients should have received a rdWBRT (23.4Gy in 13 fractions of 1.8Gy).

RESULTS

Twenty seven patients, were included. The median FU from initial diagnosis was 28.5 months [9.6–50.7]. Median age was 50.2 years [25–60]. Median Karnofsky Performans Status (KPS) was 90% [40–100%]. Seventeen patients had a multi focal disease at diagnosis (meningeal involvement n=6, in ophthalmic involvement n=4). PFS rates were 85% IC95[76–100 %], 65% IC95 [45–85%] and 65% IC95 [45–85%] at 1, 2, and 3 years respectively. The OS rates were 100%, 90,5% IC95 [77–100%] and 85%IC95 [69–100%]. 8 patients relapsed, with a median time from radiotherapy to recurrence of 6.5months [2.4–17]. All recurrences were outside the initially involved site(s), and 62.5% of tumors recurred as multifocal disease. All patients received salvage treatment, including intensive chemotherapy with autologous stem cell transplantation in 4 cases. No acute grade III-IV toxicity related to rdWBRT was reported. Neuropsychological follow up was available for 14 patients with no cognitive impairment at last follow up.

CONCLUSION

This is the largest retrospective study evaluating outcomes of rdWBRT for PCNSL young patients with CR after HD-MTX chemotherapy. Real life setting data from this study are quite reassuring, and rdWBRT could be considered as an efficient and safe consolidation strategy in this population. We need a longer FU to confirm the absence of cognitive deterioration.

OS9.7 Telomere length, TERTp mutation and ALT status in adult diffuse gliomas

BACKGROUND

The current classification of adult diffuse gliomas integrates two alternative telomere maintenance mechanisms: reactivation of telomerase activity by TERT promoter (TERTp) mutations or ATRX mutations associated with alternative length telomere (ALT). We investigated here the relation between these two mechanisms, telomere length, and outcome in a large series of diffuse gliomas.

MATERIAL AND METHODS

We performed C-circle assay (CCA) to determine ALT status, determined telomere length in tumor (RTLt) and leukocyte (RTLl) in a cohort of 354 adult diffuse gliomas, and sequenced ATRX gene. We calculated an age-adjusted telomere score considering tumor and leukocyte (blood) telomere length and corrected by age. This score was used in univariate and multivariate survival analyses to evaluate the potential impact of telomere length on the prognosis of gliomas. We used the TCGA LGG-GBM dataset to validate our findings in an independent cohort.

RESULTS

RTLl and RTLt were associated with ATRX mutation and ALT phenotype, and negatively associated with age and TERTp mutations. ATRX mutations (found in 52% (64/123) of samples) were mostly transitions (C>T or T>C), and were associated with ALT phenotype. None of 1p/19q co-deleted oligodendrogliomas harbored an ALT phenotype. No patients with TERTp mutations had ALT phenotype except for a very small subgroup of patients (3/87, 3.4%) suggesting that multiple ways of telomere maintenance, may co-exist in a single tumor, probably expressed in different clones. Telomere age-adjusted score was independently associated with better outcome (HR= 0.73 [95% CI 0.56–0.97], p-value 0.03 adjusted for age, TERTp mutation, IDH mutation, 1p/19q co-deletion and WHO grade). These results were validated using the LGG-GBM TCGA dataset.

CONCLUSION

We unravel the relation between RTLl and RTLt, TERTp mutation and ALT phenotype and describe a novel telomere age-adjusted score independently associated with better prognosis in adult diffuse gliomas.

P04.10 IDH-wildtype low grade gliomas: overall survival and prognostic indicators

BACKGROUND

IDH-wildtype WHO grade II diffuse gliomas represent a rare subgroup of low grade tumors characterized by poor prognosis. The clinical and molecular profile associated with these tumors has not been fully elucidated yet, and the ongoing uncertainties regarding their biological behavior hamper to establish a standard of treatment. The aim of this study is to define the median overall survival and the main prognostic factors associated with this rare tumor entity.

MATERIALS AND METHODS

We performed a retrospective research in our center for all patients diagnosed with diffuse WHO grade II and III gliomas from 1976 to 2018. WHO grade II and III gliomas were divided into three molecular subgroups according to the IDH1/2 mutation and the 1p/19q codeletion status (1: IDH-mutant, 1p/19q codeleted; 2: IDH-mutant, 1p/19q non codeleted; 3: IDH-wildtype). We analyzed the clinical and molecular characteristics of the three subgroups, and then the clinical, radiological, histological and molecular features of IDH-wildtype WHO grade II gliomas.

RESULTS

We identified 445 patients with diffuse WHO grade II gliomas, including 59 IDH1/2-wildtype tumors. IDH-wildtype grade II gliomas affected more frequently male (75% vs. 55%, p = 0.004) and older (mean age: 50.0 vs. 39.6 years, p<0.0001) patients, had frequent fronto-temporo-insular location (41%) and commonly underwent biopsy (53%) rather than resection. We found TERT promoter mutations (18/42, 43%), chromosome 7q gains (12/30, 40%), chromosome 10q losses (12/44, 27%), chromosome 9p losses (7/47, 15%), EGFR amplifications (5/51, 10%) and p16 deletions (4/50, 8%) but no P53 (0/16) mutations. Median overall survival was 46 months (vs. 98 for IDH-mutant non codeleted and 175 for IDH-mutant codeleted WHO grade II gliomas (p<0.0001); vs. 20 months for IDH-wildtype WHO grade III gliomas (p = 0.001)). Survival was not significantly influenced by age, preoperative KPS, tumor location, extent of resection or adjuvant treatment schemes. Chromosome 9p loss had a strong negative impact on overall survival (p=0.002).

CONCLUSION

The median overall survival associated with IDH-wildtype WHO grade II gliomas does not exceed 4 years from diagnosis. As some genetic alterations seem to have a strong prognostic impact, an exhaustive genetic assessment can be helpful in this rare tumor group for purposes of prognostic stratification and treatment decision.

P14.126 radiation-induced optic neuropathy

BACKGROUND

Optic neuropathy is an inflammation of the optic nerve leading to a rapidly progressive visual loss. Most frequent etiologies are multiple sclerosis, vasculitides, and infections. In the context of tumorous pathology, optic neuropathy can occur due to meningeal infiltration, tumoral compression, or antitumor therapeutics (radiation therapy, some targeted cancer therapies, and checkpoint inhibitors). In the current study, we examine radiation-induced optic neuropathy (RION), which is the most frequent among optic neuropathies caused by antitumor therapeutics.

MATERIAL AND METHODS

We present the cases of 3 patients who experienced RION. For each patient, we collected data on age, type of tumor, date and modalities of radiation-therapy, starting date of visual loss, ophthalmologic description, MRI images, treatment, and clinical and radiological evolution.

RESULTS

The three patients were aged 57 to 68 years old at the time of NORI. They had irradiation between 2013 and 2018. Two patients had proton therapy and one had whole brain irradiation. The visual loss occurred between seven and twelve months after the end of radiation therapy. In all patients the symptoms were bilateral and the loss of vision was rapidly worsened until culminating in almost total blindness. The MRI abnormalities were consistent with retrobulbar optic neuritis. The visual loss remained severe despite the treatment administered. High dose steroids had no clinical effect. Bevacizumab enabled a discrete subjective visual improvement in one patient, but a worsening of visual loss in another. Hyperbaric oxygen therapy had no clinical effect but was undertaken three months after the starting date of visual loss which is probably too late for efficiency. Interestingly one patient was treated with an anti-IL6 antibody (tocilizumab). It was administered in order to avoid fibrosis formation, which is the ultimate condition of the inflammatory process. The rationale is that radiation-induced opening of the bood-brain-barrier and destruction of endothelial and glial cells lead to reparation process through microglia activation. In-vitro studies showed an increased secretion of IL-6 (and other pro-inflammatory cytokines) by the activated microglia. Our patient could not experience benefit from tocilizumab, but the treatment was administered four months after the starting date of visual loss and fibrosis was probably already formed.

CONCLUSION

These cases are consistent with existing literature. The risk is mostly due to the total dose and dose per fraction of the irradiation and the prognosis is very poor with no efficient treatment at the present time. Anti-IL6 antibody could be an interesting treatment if administered at an early stage, but a future prospective clinical trial would be needed to clinically validate this hypothesis.

Ibrutinib monotherapy for relapse or refractory primary CNS lymphoma and primary vitreoretinal lymphoma: Final analysis of the phase II 'proof-of-concept' iLOC study by the Lymphoma study association (LYSA) and the French oculo-cerebral lymphoma (LOC) network

BACKGROUND

Primary central nervous system lymphomas (PCNSLs) are mainly diffuse large B-cell lymphomas (DLBCLs) of the non-germinal centre B-cell subtype, with unmet medical needs. This study aimed to evaluate the efficacy and toxicity of ibrutinib in DLBCL-PCNSL PATIENTS AND METHODS: This prospective, multicentre, phase II study involved patients with relapse or refractory(R/R) DLBCL-PCNSL or primary vitreoretinal lymphoma. The treatment consisted of ibrutinib (560 mg/day) until disease progression or unacceptable toxicity occurred. The primary outcome was the disease control (DC) rate after two months of treatment (P0 < 10%; P1 > 30%).

RESULTS

Fifty-two patients were recruited. Forty-four patients were evaluable for response. After 2 months of treatment, the DC was 70% in evaluable patients and 62% in the intent-to-treat analysis, including 10 complete responses (19%), 17 partial responses (33%) and 5 stable diseases (10%). With a median follow-up of 25.7 months (range, 0.7-30.5), the median progression-free and overall survivals were 4.8 months (95% confidence interval [CI]; 2.8-12.7) and 19.2 months (95% CI; 7.2-NR), respectively. Thirteen patients received ibrutinib for more than 12 months. Two patients experienced pulmonary aspergillosis with a favourable (n = 1) or fatal outcome (n = 1). Ibrutinib was detectable in the cerebrospinal fluid (CSF). The clinical response to ibrutinib seemed independent of the gene mutations in the BCR pathway.

CONCLUSION

Ibrutinib showed clinical activity in the brain, the CSF and the intraocular compartment and was tolerated in R/R PCNSL. The addition of ibrutinib to standard methotrexate-base induction chemotherapy will be further evaluated in the first-line treatment.

CLINICAL TRIAL NUMBER

NCT02542514.

Lenalidomide in combination with intravenous rituximab (REVRI) in relapsed/refractory primary CNS lymphoma or primary intraocular lymphoma: a multicenter prospective 'proof of concept' phase II study of the French Oculo-Cerebral lymphoma (LOC) Network and the Lymphoma Study Association (LYSA)†

BACKGROUND

Primary central nervous system lymphomas (PCNSLs) are mainly diffuse large B-cell lymphomas (DLBCLs) of the non-germinal center B-cell (non-GCB) subtype. This study aimed to determine the efficacy of rituximab plus lenalidomide (R2) in DLBCL-PCNSL.

PATIENTS AND METHODS

Patients with refractory/relapsed (R/R) DLBCL-PCNSL or primary vitreoretinal lymphoma (PVRL) were included in this prospective phase II study. The induction treatment consisted of eight 28-day cycles of R2 (rituximab 375/m2 i.v. D1; lenalidomide 20 mg/day, D1-21 for cycle 1; and 25 mg/day, D1-21 for the subsequent cycles); in responding patients, the induction treatment was followed by a maintenance phase comprising 12 28-day cycles of lenalidomide alone (10 mg/day, D1-21). The primary end point was the overall response rate (ORR) at the end of induction (P0 = 10%; P1 = 30%).

RESULTS

Fifty patients were included. Forty-five patients (PCNSL, N = 34; PVRL, N = 11) were assessable for response. The ORR at the end of induction was 35.6% (95% CI 21.9-51.2) in assessable patients and 32.0% (95% CI 21.9-51.2) in the intent-to-treat analysis, including 13 complete responses (CR)/unconfirmed CR (uCR; 29%) and 3 partial responses (PR; 7%). The best responses were 18 CR/uCR (40%) and 12 PR (27%) during the induction phase. The maintenance phase was started and completed by 18 and 5 patients, respectively. With a median follow-up of 19.2 months (range 1.5-31), the median progression-free survival (PFS) and overall survival (OS) were 7.8 months (95% CI 3.9-11.3) and 17.7 months (95% CI 12.9 to not reached), respectively. No unexpected toxicity was observed. The peripheral baseline CD4/CD8 ratio impacted PFS [median PFS = 9.5 months (95% CI, 8.1-14.8] for CD4/CD8 ≥ 1.6; median PFS = 2.8 months, [95% CI, 1.1-7.8) for CD4/CD8 < 1.6, P = 0.03).

CONCLUSIONS

The R2 regimen showed significant activity in R/R PCNSL and PVRL patients. These results support assessments of the efficacy of R2 combined with methotrexate-based chemotherapy as a first-line treatment of PCNSL.

CLINICAL TRIALS NUMBER

NCT01956695.

Angiotensin II receptor blockers, steroids and radiotherapy in glioblastoma-a randomised multicentre trial (ASTER trial). An ANOCEF study

BACKGROUND

Glioblastomas (GBMs) induce a peritumoural vasogenic oedema impairing functional status and quality of life. Steroids reduce brain tumour-related oedema but are associated with numerous side-effects. It was reported in a retrospective series that angiotensin receptor blockers might be associated with reduced peritumoural oedema. The ASTER study is a randomised, placebo-controlled trial to assess whether or not the addition of Losartan to standard of care (SOC) can reduce steroid requirement during radiotherapy (RT) in patients with newly diagnosed GBM.

PATIENTS AND METHODS

Patients with a histologically confirmed GBM after biopsy or partial surgical resection were randomised between Losartan or placebo in addition to SOC with RT and temozolomide (TMZ). The primary objective was to investigate the steroid dosage required to control brain oedema on the last day of RT in each arm. The secondary outcomes were steroids dosage 1 month after the end of RT, assessment of cerebral oedema on magnetic resonance imaging, tolerance and survival.

RESULTS

Seventy-five patients were randomly assigned to receive Losartan (37 patients) or placebo (38 patients). No difference in the steroid dosage required to control brain oedema on the last day of RT, or one month after completion of RT, was seen between both arms. The incidence of adverse events was similar in both arms. Median overall survival was similar in both arms.

CONCLUSIONS

Losartan, although well tolerated, does not reduce the steroid requirement in newly diagnosed GBM patients treated with concomitant RT and TMZ. Trial registration number NCT01805453 with ClinicalTrials.gov.

[Role of radiotherapy in the treatment of NK/T-cell nasal type and primary cerebral lymphomas]

The head and neck are common sites for extranodal non-Hodgkin lymphomas. Radiotherapy plays an important role in the treatment of low-grade lymphomas, with curative or palliative intent. In the case of high-grade lymphomas, its combination with chemotherapy is debated. Its role is however undeniable in two specific entities: NK/T-cell lymphoma NK/T nasal type, and primary central nervous system lymphomas, which are the subject of this review.

Posterior reversible encephalopathy syndrome (PRES) and hypomagnesemia: A frequent association?

Posterior reversible encephalopathy syndrome (PRES) is a serious neurological condition encountered in various medical fields. Pathophysiological factor(s) common to PRES cases of apparently unrelated etiologies are yet to be found. Based on the hypothesis that hypomagnesemia might participate in the cascade leading to PRES, our study sought to verify whether hypomagnesemia is frequently associated with PRES regardless of etiology. From a retrospective study of a cohort of 57 patients presenting with PRES of different etiologies, presented here are the findings of 19 patients with available serum magnesium levels (SMLs) during PRES. In the acute phase of PRES, hypomagnesemia was present in all 19 patients in spite of differences in etiology (including immunosuppressive drugs, hypertensive encephalopathy, eclampsia, systemic lupus erythematosus, iatrogenic etiology and unknown). SMLs were within normal ranges prior to PRES and below normal ranges during the first 48h of PRES, with a significant decrease in SMLs during the acute phase. In this retrospective study, constant hypomagnesemia was observed during the acute phase of PRES regardless of its etiology. These results now require larger studies to assess the particular importance of acute hypomagnesemia in PRES and especially the possible need to treat PRES with magnesium sulfate.

First-line treatment and outcome of elderly patients with primary central nervous system lymphoma (PCNSL)--a systematic review and individual patient data meta-analysis

BACKGROUND

To investigate prognosis and effects of first-line therapy in elderly primary central nervous system lymphoma (PCNSL) patients.

PATIENTS AND METHODS

A systematic review of studies about first-line therapy in immunocompetent patients ≥60 years with PCNSL until 2014 and a meta-analysis of individual patient data from eligible studies and international collaborators were carried out.

RESULTS

We identified 20 eligible studies; from 13 studies, we obtained individual data of 405 patients, which were pooled with data of 378 additional patients (N = 783). Median age and Karnofsky Performance Score (KPS) was 68 years (range: 60-90 years) and 60% (range: 10%-100%), respectively. Treatments varied greatly, 573 (73%) patients received high-dose methotrexate (HD-MTX)-based therapy. A total of 276 patients received whole-brain radiotherapy (median 36 Gy, range 28.5-70 Gy). KPS ≥ 70% was the strongest prognostic factor for mortality [hazard ratio (HR) 0.50, 95% confidence interval (CI) 0.41-0.62]. After a median follow-up of 40 months, HD-MTX-based therapy was associated with improved survival (HR 0.70, 95% CI 0.53-0.93). There was no difference between HD-MTX plus oral chemotherapy and more aggressive HD-MTX-based therapies (HR 1.39, 95% CI 0.90-2.15). Radiotherapy was associated with an improved survival, but correlated with an increased risk for neurological side-effects (odds ratio 5.23, 95% CI 2.33-11.74).

CONCLUSIONS

Elderly PCNSL patients benefit from HD-MTX-based therapy, especially if combined with oral alkylating agents. More aggressive HD-MTX protocols do not seem to improve outcome. WBRT may improve outcome, but is associated with increased risk for neurological side-effects. Prospective trials for elderly PCNSL patients are warranted.

TERT promoter mutations in gliomas, genetic associations and clinico-pathological correlations

BACKGROUND

The role of telomerase reverse transcriptase (TERT) in gliomagenesis has been recently further strengthened by the frequent occurrence of TERT promoter mutations (TERTp-mut) in gliomas and evidence that the TERT SNP genetic rs2736100 influences glioma risk. TERTp-mut creates a binding site for Ets/TCF transcription factors, whereas the common rs2853669 polymorphism disrupts another Ets/TCF site on TERT promoter.

METHODS

We sequenced for TERTp-mut in 807 glioma DNAs and in 235 blood DNAs and analysed TERT expression by RT-PCR in 151 samples. TERTp-mut status and TERTp polymorphism rs2853669 were correlated with histology, genomic profile, TERT mRNA expression, clinical outcome and rs2736100 genotype.

RESULTS

TERTp-mut identified in 60.8% of gliomas (491 out of 807) was globally associated with poorer outcome (Hazard ratio (HR)=1.50). We defined, based on TERTp-mut and IDH mutation status, four prognostic groups: (1) TERTp-mut and IDH-mut associated with 1p19q codeletion, overall survival (OS)>17 years; (2) TERTp-wt and IDH-mut, associated with TP53 mutation, OS=97.5 months; (3) TERTp-wt and IDH-wt, with no specific association, OS=31.6 months; (4) TERTp-mut and IDH-wt, associated with EGFR amplification, OS=15.4 months. TERTp-mut was associated with higher TERT mRNA expression, whereas the rs2853669 variant was associated with lower TERT mRNA expression. The mutation of CIC (a repressor of ETV1-5 belonging to the Ets/TCF family) was also associated with TERT mRNA upregulation.

CONCLUSIONS

In addition to IDH mutation status, defining the TERTp-mut status of glial tumours should afford enhanced prognostic stratification of patients with glioma. We also show that TERTp-mut, rs2853669 variant and CIC mutation influence Tert expression. This effect could be mediated by Ets/TCF transcription factors.