Wipplinger, Tamara

Abstract Background Imaging-based glioma monitoring is confounded by treatment-related changes. D-2-hydroxyglutarate (D-2-HG), produced by the isocitrate dehydrogenase (IDH) mutation, is detectable in cerebrospinal fluid (CSF), which can be sampled from cranial or lumbar compartments. We evaluated CSF D-2-HG as a serially accessible biomarker for IDH-mutant gliomas, including the optimal compartment for longitudinal sampling. Methods Lumbar and cranial CSF samples were collected from patients with IDH-mutant gliomas or IDH-wild-type central nervous system pathologies via surgical field collection, lumbar punctures, and CSF access devices. CSF D-2-HG was quantified via our CLIA-certified gas chromatography mass spectrometry assay. Results D-2-HG was significantly higher in cranial than lumbar CSF from IDH-mutant glioma patients. Consistent with low D-2-HG abundance in lumbar CSF, lumbar samples could not discriminate IDH-mutant gliomas from IDH-wild-type lesions. In contrast, cranial CSF D-2-HG was significantly higher in IDH-mutant gliomas than wild-type lesions, providing an adequate baseline for initial evaluations of monitoring capabilities. Across 75 samples from 7 consecutive patients with grade 4 IDH-mutant astrocytomas, serial cranial CSF D-2-HG decreased with cytoreduction, remained unchanged with stable disease, and increased with disease progression, but not pseudoprogression. Conclusions Serial cranial CSF D-2-HG shows promise as a monitoring biomarker for IDH-mutant gliomas.

Abstract Polyamines are small molecules that play a critical role in tumor progression and in the regulation of immune responses within the tumor microenvironment. Elevated levels of polyamines in cerebrospinal fluid and tumor tissue have been reported in multiple studies and are shown to correlate with glioma grade. These findings suggest that the polyamine metabolic pathway may represent a therapeutic target in gliomas. Difluoromethylornithine (DFMO) is an irreversible inhibitor of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis, expected to exert antitumor effects through polyamine depletion. Although the impact of DFMO against glioblastoma as a monotherapy appears limited, opportunities for synergy with other therapies remain understudied. In this study, we evaluated the therapeutic efficacy of DFMO using both in vitro and in vivo experiments with a murine glioma model (CT-2A) and patient-derived xenograft (PDX) cell lines. Among the models tested, CT-2A cells exhibited the highest expression of ODC1 and demonstrated strong sensitivity to DFMO in vitro. We compared two CT-2A variants: a commercially available line responsive to immunotherapy, and a widely used subline resistant to PD-1 blockade. While DFMO did not improve survival in mice implanted with the immunotherapy-sensitive commercial CT-2A line, it extended median survival by 8 days in mice bearing tumors derived from the immunotherapy-resistant subline. Transcriptomic analysis revealed that the DFMO-responsive, immunotherapy-resistant tumors exhibited lower baseline expression of immune-related genes, including those involved in interferon-β, interferon-γ, and IL-12 signaling pathways, compared to the immunotherapy-sensitive tumors. The latter showed markedly higher expression of STAT1 and interferon-γ and were enriched for immune-related Gene Ontology terms. These findings suggest that polyamine-targeted therapy may be appropriate for gliomas with an immunosuppressive, “cold” phenotype. Ongoing RNA sequencing analyses aim to further elucidate the immunomodulatory mechanisms of DFMO, and other agents comprising an adaptive toolkit to optimize and sustain anti-tumoral immunity.

Abstract Imaging-based monitoring of gliomas is hampered by treatment-related changes, as well as the insidious growth of gliomas harboring the isocitrate dehydrogenase (IDH) mutation. The IDH mutation results in elevated D-2-hydroxyglutarate (D-2-HG), which is detectable in cerebrospinal fluid (CSF) that can be accessed longitudinally from multiple compartments, including cranially via CSF access devices. As such, we evaluated the early utility of CSF D-2-HG as a serially accessible biomarker for IDH-mutant gliomas. A CLIA-approved gas chromatography mass spectrometry assay was developed for CSF D- and L-2-HG. Lumbar and cranial CSF samples were collected from patients with IDH-mutant gliomas or IDH-wild-type brain tumors and non-tumor pathologies via surgical field collection, lumbar punctures, Ommaya reservoirs, and ventriculoperitoneal shunts. First, to confirm the ability of CSF D-2-HG to detect IDH-mutant gliomas, concentrations were compared between IDH-mutant gliomas and wild-type lesions. Cranial, but not lumbar, CSF D-2-HG distinguished primary IDH-mutant gliomas from IDH-wild type lesions (cranial AUC= 0.89, 95% confidence interval (CI)= 0.80-0.97); lumbar AUC= 0.52, 95% CI=0.28-0.76). Indeed, CSF D-2-HG was significantly higher in cranial than lumbar samples from IDH-mutant glioma patients (median lumbar=0.20 μM, cranial = 1.72 μM; p<0.0001), confirming a significantly elevated abundance of CSF D-2-HG only in cranial CSF from IDH-mutant gliomas. Then, response to cytoreduction was evaluated, demonstrating that cranial CSF D-2-HG levels decreased to 0.54x of baseline with resection in seventeen patients (p=0.0129). Changes in tumor-to-CSF contact impacted the serial evaluation of CSF D-2-HG prior to versus after chemoradiation in some patients. Nevertheless, in patients with grade 4 IDH-mutant astrocytomas, serial cranial CSF D-2-HG increased with disease progression and differentiated stability from pseudoprogression when tumor-CSF contact was sufficient. In conclusion, serial cranial CSF D-2-HG shows promise as a monitoring biomarker in patients with IDH-mutant gliomas, although anatomic variables must be considered in parallel to CSF D-2-HG evaluation.

BACKGROUND AND OBJECTIVES: Brainstem cavernous malformations (BSCM) can result in spontaneous intracerebral hemorrhage (ICH), often resulting in significant morbidity. We aimed to assess the functional outcome and identify predictors of functional neurological outcome after single and multiple symptomatic hemorrhages. METHODS: As part of an international multicenter collaboration, institutional databases from 3 different tertiary referral centers included BSCM patients with complete baseline characteristics, MRI Data set, ≥1 ICH, and ≥1 follow-up examination followed at our institutions between 2003 and 2023. Functional neurological outcome was obtained using the modified Rankin Scale at diagnosis, before and after each ICH, and last follow-up. Patients were excluded after surgical removal of the lesion and/or loss of follow-up. RESULTS: A total of 383 patients (41.47 ± 15.51 age; 220 [57.4%] female) were included and followed for an average of 63.16 ± 85.75 months. Functional neurological outcome deteriorated in 47.2% ( P = .010) after the second ICH and in 46.5% ( P = .007) after the third ICH. Moreover, the functional neurological status was impaired in 22.3% ( P < .001) of patients at last available follow-up compared with the time of BSCM diagnosis. CONCLUSION: In our study, we observed that the chance of full recovery might decrease with each ICH. We observed a significantly associated neurological deterioration after each ICH compared with initial ICH.

OBJECTIVE Stereotactic radiosurgery (SRS) offers excellent tumor control for pituitary adenoma (PA); however, treatment failure occasionally necessitates salvage surgery. Comprehensive studies on salvage surgical outcomes for recurrent PA after SRS remain scarce. This study aimed to elucidate the outcomes of salvage endonasal transsphenoidal surgery (sETS) for progressive PA failing SRS. METHODS This retrospective, two institution–based cohort study analyzed data from patients who underwent sETS for progressive PA failing SRS. Progression-free survival (PFS), disease-specific survival (DSS), and neurological and endocrinological outcomes in the sETS group were analyzed and compared with those in the primary ETS (pETS) group after propensity score matching using the following variables: age at surgery, maximum tumor diameter, highest Knosp–Steiner classification, and tumor type. RESULTS Thirteen sETS patients (8 males [62%], median age at surgery of 56 years) with 5 nonfunctioning (39%), 6 corticotropic (46%), and 2 other functioning (15%) PAs who received median (range) follow-up of 125 ( 23–169) months were included. None of the patients experienced new neurological deficits or death after sETS. The median (range) tumor resection rate was 90% (80%–100%). The 5-year PFS and DSS rates were 55% and 77%, respectively. All 4 patients (31%) who experienced recurrence after sETS had corticotropic tumors. In the matched cohort analysis between the sETS group with 12 patients and the pETS group with 12 patients, no significant differences were observed in surgical outcomes. PFS rates were marginally higher in the sETS group than in the pETS group (80% vs 49% at 3 years, p = 0.216, log-rank test), and DSS was similar between the two groups (p = 0.543, log-rank test). CONCLUSIONS The authors’ results indicate that ETS can be safely performed as a salvage treatment after failed SRS with low complication rates and satisfactory tumor control in treatment-resistant PA.

Abstract Background Recent technologic advancements have facilitated the use of hypofractionated Gamma Knife-based radiosurgery (HF-GKRS) to treat large lesions or those in eloquent areas. This study aimed to analyze the preliminary results of HF-GKRS for these meningiomas, and to determine its effectiveness and safety. Methods This single-center retrospective study analyzed data of patients who underwent HF-GKRS for large meningiomas or those in eloquent areas with > 6 months of follow-up. The primary outcome was progression-free survival (PFS). The secondary outcomes were neurological deterioration, post-treatment T2 signal changes following HF-GKRS, and tumor volume changes. Volumetric analysis of the tumors after treatment was also performed to assess changes in tumor size after HF-GKRS. Results Overall, 24 patients with a median follow-up period of 22 months (range: 6–49 months) were included. Among them, 18 (75%) patients had tumors in close proximity to the optic pathway, and 15 (63%) patients had large lesions (> 10 cm3). The cumulative 1- and 3-year PFS rates were 100% and 92%, respectively. The cumulative 3-year rate of adverse radiation effects was 9%. Overall, 12 patients (50%) showed tumor reduction, with a median tumor reduction rate of 45% (range: 25–58%). Conclusions Our preliminary results revealed that HF-GKRS for large meningiomas or those in eloquent areas is safe and effective, with satisfactory short- and mid-term PFS and low adverse radiation effects. Further research with more patients and longer follow-up periods is required.