Epilepsy in Patients With Primary CNS Lymphoma: Prevalence, Risk Factors, and Prognostic Significance.

BACKGROUND AND OBJECTIVES: Epilepsy is a common comorbidity of brain tumors; however, little is known about the prevalence, onset time, semiology, and risk factors of seizures in primary CNS lymphoma (PCNSL). Our objectives were to determine the prevalence of epilepsy in PCNSL, to identify factors associated with epilepsy, and to investigate the prognostic significance of seizures in PCNSL. METHODS: We performed an observational, retrospective single-center study at a tertiary neuro-oncology center (2011-2023) including immunocompetent patients with PCNSL and no history of seizures. We collected clinical, imaging, and treatment data; seizure status over the course of PCNSL; and oncological and seizure outcome. The primary outcome was to determine the prevalence of epilepsy. Furthermore, we aimed to identify clinical, radiologic, and treatment-related factors associated with epilepsy. Univariate analyses were conducted using the χ2 test for categorical variables and unpaired t test for continuous variables. Predictors identified in the unadjusted analysis were included in backward stepwise logistic regression models. RESULTS: We included 330 patients, 157 (47.6%) were male, median age at diagnosis was 68 years, and the median Karnofsky Performance Status score was 60. Eighty-three (25.2%) patients had at least 1 seizure from initial diagnosis to the last follow-up, 40 (12.1%) as the onset symptom, 16 (4.8%) during first line of treatment, 27 (8.2%) at tumor progression and 6 (1.8%) while in remission. Focal aware seizures were the most frequent seizure type, occurring in 43 (51.8%) patients. Seizure freedom under antiseizure medication was observed in 97.6% patients. Cortical contact (odds ratio [OR] 8.6, 95% CI 4.2-15.5, p < 0.001) and a higher proliferation index (OR 5.7, 95% CI 1.3-26.2, p = 0.02) were identified as independent risk factors of epilepsy. Patients with PCNSL and epilepsy had a significantly shorter progression-free survival (median progression-free survival 9.6 vs 14.1 months, adjusted hazard ratio 1.4, 95% CI 1.0-1.9, p = 0.03), but not a significantly shorter overall survival (17 vs 44.1 months, log-rank test, p = 0.09). DISCUSSION: Epilepsy affects a quarter of patients with PCNSL, with half experiencing it at the time of initial presentation and potentially serving as a marker of disease progression. Further research is necessary to assess the broader applicability of these findings because they are subject to the constraints of a retrospective design and tertiary center setting.

Cerebellum/liver index on baseline 18F-FDG PET/CT to improve prognostication in post-transplant lymphoproliferative disorders: a multicenter retrospective study.

BACKGROUND: Besides International Prognostic Index (IPI) score, baseline prognostic factors of post-transplant lymphoproliferative disorders (PTLD) are poorly identified due to the rarity of the disease. New indexes derived from healthy organ uptake in baseline 18F-FDG PET/CT have been studied in immunocompetent lymphoma patients. The aim of this study is to evaluate the performances of the cerebellum-to-liver uptake ratio (denoted as CLIP) as a prognostic factor for PFS and OS. This retrospective multicenter study is based on patients with PTLD included in the K-VIROGREF cohort. The previously published threshold of 3.24 was used for CLIP in these analyses. RESULTS: A total of 97 patients was included with a majority of monomorphic diffuse large B-cell lymphoma subtype (78.3%). Both IPI score (≥ 3) and CLIP (< 3.24) were significant risk factors of PFS with corresponding hazard ratios of 2.0 (1.0-4.0) and 2.4 (1.3-4.5) respectively. For OS, CLIP was not significant and resulted in a hazard ratio of 2.6 (p = 0.059). Neither IPI score or Total Metabolic Tumor Volume reached significance for OS. CONCLUSION: CLIP is a promising predictor of PFS and perhaps OS in PTLD. Further prospective studies are needed to confirm these results.

Feasibility of Liver Transplantation after 90 Y Radioembolization: Lessons from a Radiation Protection Incident.

ABSTRACT: Radioembolization using 90 Y is a growing procedure in nuclear medicine for treating hepatocellular carcinoma. Current guidelines suggest postponing liver transplantation or surgical resection for a period of 14 to 30 d after radioembolization to minimize surgeons' exposure to ionizing radiation. In light of a radiation protection incident, we reevaluated the minimum delay required between radioembolization and subsequent liver transplantation. A patient with a hepatocellular carcinoma underwent a liver transplantation 44 h after undergoing radioembolization using 90 Y (860 MBq SIR-Spheres). No specific radioprotection measures were followed during surgery and pathological analysis. We subsequently (1) evaluated the healthcare professionals' exposure to ionizing radiation by conducting dose rate measurements from removed liver tissue and (2) extrapolated the recommended interval to be observed between radioembolization and surgery/transplantation to ensure compliance with the radiation dose limits for worker safety. The surgeons involved in the transplantation procedure experienced the highest radiation exposure, with whole-body doses of 2.4 mSv and extremity doses of 24 mSv. The recommended delay between radioembolization and liver transplantation was 8 d when using SIR-Spheres and 15 d when injecting TheraSphere. This delay can be reduced further when considering the specific 90 Y activity administered during radioembolization. This dosimetric study suggests the feasibility of shortening the delay for liver transplantation/surgery after radioembolization from the 8th or 15th day after using SIR-Spheres or TheraSphere, respectively. This delay can be decreased further when adjusted to the administrated activity while upholding radiation protection standards for healthcare professionals.

Interim FDG-PET improves treatment failure prediction in primary central nervous system lymphoma: An LOC network prospective multicentric study.

BACKGROUND: The purpose of our study was to assess the predictive and prognostic role of 2-18F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)/MRI during high-dose methotrexate-based chemotherapy (HD-MBC) in de novo primary central nervous system lymphoma (PCNSL) patients aged 60 and above. METHODS: This prospective multicentric ancillary study included 65 immunocompetent patients who received induction HD-MBC as part of the BLOCAGE01 phase III trial. FDG-PET/MRI were acquired at baseline, post 2 cycles (PET/MRI2), and posttreatment (PET/MRI3). FDG-PET response was dichotomized with "positive" indicating persistent tumor uptake higher than the contralateral mirroring brain region. Performances of FDG-PET and International PCNSL Collaborative Group criteria in predicting induction response, progression-free survival (PFS), and overall survival (OS) were compared. RESULTS: Of the 48 PET2 scans performed, 9 were positive and aligned with a partial response (PR) on MRI2. Among these, 8 (89%) progressed by the end of the induction phase. In contrast, 35/39 (90%) of PET2-negative patients achieved complete response (CR). Among the 18 discordant responses at interim (PETCR/MRIPR), 83% ultimately achieved CR. Eighty-seven percent of the PET2-negative patients were disease free at 6 months versus 11% of the PET2-positive patients (P < .001). The MRI2 response did not significantly differentiate patients based on their PFS, regardless of whether they were in CR or PR. Both PET2 and MRI2 independently predicted OS in multivariate analysis, with PET2 showing a stronger association. CONCLUSIONS: Our study highlights the potential of interim FDG-PET for early management of PCNSL patients. Response-driven treatment based on PET2 may guide future clinical trials. TRIAL: LOCALYZE, NCT03582254, ancillary of phase III clinical trial BLOCAGE01, NCT02313389 (Registered July 10, 2018-retrospectively registered) https://clinicaltrials.gov/ct2/show/NCT03582254?term=LOCALYZE&draw=2&rank=1.

Exploring the mechanism of 18F-fluorodopa uptake in recurrent high-grade gliomas: A comprehensive histomolecular-positron emission tomography analysis.

BACKGROUND: Dihydroxy-6-[18F]fluoro-L-phenylalanine (18F-FDOPA) positron emission tomography (PET) is a valuable tool for managing high-grade gliomas (HGGs), but there is a lack of literature on its relationship with glioma subtypes since the 2021 reclassification of brain tumors. There is also debate surrounding the mechanism of 18F-FDOPA uptake, particularly after chemoradiation therapy. This study aimed to investigate the correlation between 18F-FDOPA uptake and histomolecular characteristics, particularly L-amino acid transporter 1 (LAT1) expression, in recurrent gliomas, and examine their impact on survival in HGGs. METHODS: Thirty-nine patients with recurrent HGGs (14 isocitrate dehydrogenase [IDH]-mutant, 25 IDH-wildtype) who underwent a brain 18F-FDOPA PET/computed tomography (CT) or PET/magnetic resonance imaging (MRI) followed by surgical resection of the 18F-FDOPA-avid lesion within 6 months, were retrospectively reviewed. PET results were compared with histological examination and for SCL7A5/LAT1 immunostaining. The study also examined the relationship between PET parameters, LAT1 expression, and survival outcomes. RESULTS: Astrocytoma IDH-mutant G4 had higher 18F-FDOPA uptake than glioblastoma IDH-wildtype G4 (maximum tumor-to-normal brain ratio [TBRmax] 5 [3.4-9] vs. 3.8 [2.8-5.9], p = 0.02). IDH-mutant gliomas had higher LAT1 expression than IDH-wildtype gliomas (100 [14-273] vs. 15.5 [0-137], p < 0.05) as well as higher TBRmax (5 [2.4-9] vs. 3.8 [2.8-6], p < 0.05). In survival analysis, LAT1 score >100 was a predictor for longer progression-free survival in IDH-mutant HGGs. CONCLUSIONS: To our knowledge, our study is the first to suggest a link between LAT1 expression and IDH mutation status. We showed that higher TBRmax was associated with higher LAT1 expression and IDH mutation status. Further studies are needed to better understand the mechanisms underlying amino acid PET tracers uptake, especially in the post-radiation and chemotherapy settings.

Frontal presentation of Alzheimer's disease: a series of patients with biological evidence by CSF biomarkers / Apresentação frontal da doença de Alzheimer: uma série de pacientes com evidência biológica por biomarcadores no LCR

Besides its typical amnesic presentation, focal atypical presentations of Alzheimer's disease (AD) have been described in neuropathological studies. These phenotypical variants of AD (so-called "atypical AD") do not follow the typical amnestic pattern and include non-amnestic focal cortical syndromes, such as posterior cortical atrophy and frontal variant AD. These variants exhibit characteristic histological lesions of Alzheimer pathology at post-mortem exam. By using physiopathological markers, such as cerebrospinal fluid markers, it is now possible to establish in vivo a biological diagnosis of AD in these focal cortical syndromes. We report a series of eight patients who were diagnosed with behavioural variant frontotemporal dementia based on their clinical, neuropsychological and neuroimaging findings, while CSF biomarkers showed an AD biological profile, thus supporting a diagnosis of frontal variant of AD.

Além da típica forma amnésica, apresentações focais atípicas da doença de Alzheimer (DA) foram descritas em estudos anatomopatológicos. Essas variantes fenotípicas da DA ("DA atípica") não seguem o padrão amnésico convencional e incluem síndromes corticais focais não amnésicas, tais como a atrofia cortical posterior e a variante frontal da DA. Essas variantes apresentam lesões histológicas características da DA ao exame patológico post-mortem. O uso de marcadores fisiopatológicos da DA, como os biomarcadores do líquido cefalorraquidiano, permite estabelecer in vivo um diagnóstico biológico de DA nessas síndromes corticais focais. Reportamos uma série de oito pacientes que foram clinicamente diagnosticados como portadores da variante comportamental da demência frontotemporal (de acordo com critérios clínicos, neuropsicológicos e de neuroimagem), mas nos quais a investigação dos biomarcadores do líquor mostrou um perfil biológico de DA, de modo que o diagnóstico da variante frontal de DA foi finalmente estabelecido.