Citations

Abstract Circumscribed meningeal melanocytic neoplasms (CMMNs) represent a spectrum of rare central nervous system (CNS) tumors. Knowledge of their clinical behavior and molecular correlates remains limited. In this single‐institution retrospective study, we analyzed 31 patients (14 male, 17 female; median age, 59 years) diagnosed with CMMN between 2004 and 2025. In this patient cohort, based on the current World Health Organization Central Nervous System Tumor Classification (WHO CNS5) criteria, the majority of cases (18, 58.1%) fell into the intermediate‐grade melanocytic tumor (IMT) category based on histology, with either increased mitotic activity, CNS invasion, or both; 7 (22.6%) were melanocytomas, 5 (16.1%) melanomas, and 1 (3.2%) indeterminate case because of limited tissue. By next‐generation sequencing, mutations were identified in GNAQ/GNA11 in 21/24 cases, BAP1 in 5/23 (2 IMT, 3 melanoma), EIF1AX in 9/21 (1 melanocytoma, 8 IMT), and SF3B1 in 3/23 (2 IMT, 1 melanoma). Primary sites were spinal (20), posterior fossa (6), and supratentorial (5). During follow‐up, progression was observed in 5/6 melanocytomas, 9/13 IMTs, and 4/5 melanomas, suggesting a high frequency of progression across all groups. Two‐year progression‐free survival was 83.3% (95% confidence interval [CI], 53.5%–100.0%) for melanocytoma, 55.9% (95% CI, 26.7%–85.2%) for IMT, and 25.0% (95% CI, 0.0%–67.4%) for melanoma. Five‐year overall survival (OS) was 80.0% (95% CI, 44.9%–100.0%) for melanocytoma, 65.3% (95% CI, 37.0%–93.6%) for IMT, and 0.0% for melanoma. OS was significantly worse in melanoma compared with melanocytoma ( p = 0.002). BAP1 mutation correlated with worse OS (hazard ratio 8.73, p = 0.006). Upfront maximal safe resection appeared to be associated with improved outcomes in selected patients, whereas radiotherapy and systemic therapy did not demonstrate clear additional benefit in this cohort. In summary, our study shows that all CMMNs, irrespective of grade, have a high propensity to recur and melanoma histology and BAP1 mutation are associated with significantly worse OS.

BACKGROUND Laser interstitial thermal therapy is a minimally invasive surgical technique commonly used for treating epileptogenic foci in patients with drug-resistant epilepsy. Densely calcified lesions pose a challenge because they prevent the placement of a laser cannula within them and act as a heat shield. A 22-year-old male presented with intractable epilepsy with imaging demonstrating a densely calcified lesion in the right medial occipitotemporal gyrus radiographically consistent with a polymorphous low-grade neuroepithelial tumor of the young. OBSERVATIONS Two laser cannulas were stereotactically positioned to flank the centrally calcified portion of the lesion at its anterior and posterior aspects. Intraoperative MR thermography during each ablation showed that the dense calcification shielded ablative heating from spreading to the other side of the lesion. The sum of the thermal ablation zones covered the entirety of the lesion. Postprocedure MRI demonstrated overlapping peripherally enhancing ablation zones, which subsumed the entirety of the calcified mass. The patient tolerated the procedure well and remained seizure free at the 14-month follow-up. LESSONS Using multiple stereotactically placed laser filaments to flank epileptogenic lesions that are densely calcified is a strategy to effectively encompass the entirety of the lesion within the combined ablation zones. https://thejns.org/doi/10.3171/CASE26184

TPS2103 Background: Treatment for newly diagnosed IDH-mutant astrocytoma, WHO grade 3, is based on the results of the CATNON study, demonstrating benefit of radiotherapy followed by 12 months of adjuvant temozolomide. While temozolomide and radiotherapy significantly improved survival, the prognosis for these patients remains limited and more effective therapies are required. This trial will evaluate the benefit of the addition of the IDH1 and IDH-2 inhibitor vorasidenib to adjuvant temozolomide versus placebo following standard radiotherapy to evaluate possible improvement in outcomes. Methods: Alliance A072301 (NCT07215910) is a multicenter, double-blinded phase 3 randomized study to determine if the addition of vorasidenib to adjuvant temozolomide significantly improves progression-free survival (PFS), based on blinded central review in patients with newly diagnosed, IDH-mutant astrocytoma, WHO grade 3. Key inclusion criteria include age ≥ 12 years old, histological confirmation of astrocytoma (absence of 1p/19q codeletion), WHO grade 3, presence of any IDH mutation, plan for radiation and chemotherapy and surgery within 6 months. The presence of CDKN2A/B homozygous deletion, spinal or leptomeningeal disease, as well as prior chemotherapy, cranial irradiation or IDH inhibitor therapy, is exclusionary. 408 patients will be randomized 1:1 to receive vorasidenib 40 mg or placebo daily with 12 cycles of temozolomide following radiotherapy and then continued as monotherapy until disease progression or unacceptable toxicity. Stratification factors include age (< 40 years old vs ≥ 40 years old) and residual disease (< 2 cm vs ≥ 2 cm). Tumor assessments with MRI will be every three months for the first two years, every four months for the next two years and then every six months thereafter as per blinded independent central review using the Response Assessment in Neuro-Oncology (RANO) 2.0 criteria. Key secondary endpoints include PFS by local review, time to next treatment, safety and tolerability, quality of life measures. Exploratory measures will include seizure frequency. The trial will have 85% power to detect a hazard ratio of 0.625 with one-sided type I error rate of 0.025. Enrollment for the trial commenced February 2026. Support: U10CA180821, U10CA180882, U24CA196171. https://acknowledgments.alliancefound.org.

2016 Background: Bevacizumab therapy (Bev) for recurrent glioblastoma (rGBM) has not demonstrated improved overall survival (OS) in randomized clinical trials. However, single-center and preliminary multi-center studies suggest that relative cerebral blood volume (rCBV) measured with dynamic susceptibility contrast MRI (DSC-MRI) at baseline or shortly after treatment initiation may predict response to Bev. The primary aim of ECOG-ACRIN EAF151 was to evaluate whether early binary change in rCBV, assessed 2–3 weeks after initiation of Bev-containing therapy, identifies patients with an OS benefit of ≥4 mos. Pre-specified secondary aims assessed baseline rCBV; post-hoc exploratory analyses examined early post-Rx rCBV. Methods: A prospective, phase II multi-center trial without randomization enrolled subjects with rGBM receiving their first Bev-containing therapy. Progression was determined by local sites (RANO criteria; MRI within 28 days of registration, ≥42 days since end of chemoradiation). Baseline (S0) and follow-up (S1) DSC-MRI were performed before the first Bev infusion (within 3 days), and 12-25 days post-infusion but before the second infusion. Anatomic MRI and DSC-MRI (double-dose Gadavist injection, full-dose preload) complied with recommended protocols. Mean normalized (nRCBV) and standardized (sRCBV) rCBV were extracted from contrast-enhancing tumor ROIs. A 2-sided logrank test (α=0.1) was used to test the primary aim (change in mean nRCBV from S0 to S1, ≥0 vs. <0). Cox regression with restricted cubic splines was used to assess the association between continuous rCBV markers and OS. Results: 146 subjects were accrued from 33 sites. 134 completed S0 and 118 completed both S0 and S1. After exclusion of uninterpretable scans, 107 were evaluable for change in rCBV, and 124 for baseline rCBV. There was no statistically significant difference in OS between subjects with binary increase (n=40; median OS 8.0 mos [90% CI 5.5–9.2]) vs. decrease (n=67; 7.9 mos [90% CI 6.3–10.3]) in mean nRCBV (p=0.67). Based on the spline fits, we observed a strong nonlinear association between OS and continuous nRCBV and sRCBV at both S0 and S1: low marker values are associated with lower risk, but beyond a threshold, higher values are not associated with greater risk. As an exploratory analysis, we estimated optimal cut points (nRCBV: S0=1.11, S1=1.16; sRCBV: S0=1.13, S1=0.99) and found that subjects whose S1 rCBV decreased below threshold had a median OS 2.7 mos (nRCBV, HR 0.61 [90% CI 0.41–0.88]) and 5.2 mos (sRCBV, HR 0.43 [90% CI 0.28–0.63]) longer than subjects whose rCBV either increased or did not decrease below threshold. Conclusions: EAF151 prospectively evaluated whether DSC-MRI markers predict OS in patients with rGBM treated with Bev. Although the change in these markers was not predictive, both baseline and early post-Rx markers were predictive of OS. Clinical trial information: NCT03115333 .

Lay Summary Accurately differentiating actual tumor progression from treatment-related changes, such as pseudoprogression or radiation-induced injury, remains one of the most critical diagnostic challenges in neuro-oncology for both primary and secondary brain tumors. Conventional MRI often lacks specificity because it primarily reflects blood-brain barrier disruption rather than viable tumor tissue. Consequently, advanced techniques like perfusion-weighted MRI and amino acid PET have gained significant attention. While perfusion-weighted MRI provides essential insights into blood flow and is widely available, accumulating evidence suggests that amino acid PET can be more reliable in identifying treatment-related changes. Since both modalities offer complementary information, there is an ongoing debate regarding their relative roles and the optimal way to integrate them into clinical practice. Combining these tools aims to provide more reliable diagnoses, ultimately preventing unnecessary interventions and ensuring that true tumor growth is detected as early as possible.

Abstract Background: Pembrolizumab has been increasingly used off label for recurrent gliomas, yet biomarkers predicting response are poorly defined. Gliomas exhibit substantial molecular heterogeneity across Glioblastoma, IDH-wildtype (GBM), Astrocytoma, IDH-Mutant (A-IDHm), and Oligodendroglioma, 1p/19q co-deleted (OLIGO), which may influence immunotherapy efficacy. This study aimed to identify molecular predictors of progression-free survival (PFS) in recurrent glioma patients treated with pembrolizumab. Methods: Adults ≥18 years with recurrent glioma receiving ≥2 cycles of pembrolizumab between 2014 - 2024 were retrospectively identified across Mayo Clinic. Next-generation sequencing (NGS) reports were reviewed and archival tumor tissue resected prior to pembrolizumab initiation was analyzed when available. Comprehensive molecular profiling was performed using the Mayo Clinic Solid Tumor Panel which employs the Illumina Tru-Sight Oncology 500 High-Throughput NGS assay. Progression was assessed using RANO 2.0 criteria. Genomic alterations (clinically relevant sequences and/or copy-number variants) were evaluated using the Kaplan-Meier method, with differences in PFS compared using the log-rank test. Results: Thirty-three patients were included [median (range) age: 44.0 (21-76) years; 63.6% male]. The interval between tumor tissue sampling and pembrolizumab initiation was 9.9 (0.9-176.1) months, and median treatment duration was 2.8 (1.4-10.4) months. Median PFS for the overall cohort was 2.4 (0.8-15.2) months, and median overall survival from pembrolizumab initiation was 6.9 (0.9-48.2) months. Patients with OLIGO (n=8) had a longer PFS [4.6 (1.9-15.2) months] than either A-IDHm [n=11; PFS 2.1 (1.1-4.4) months] or GBM [n=14; PFS 2.3 (0.8-9.2) months]. Within OLIGO, CDKN2A/B heterozygous deletion (n=3) predicted a shorter PFS (3.9 vs 10.9 months; p=0.0462), while in A-IDHm, FANC mutation (n=2) was associated with a longer PFS (4.17 vs 1.61 months; p=0.0224). No significant associations with PFS were observed for other altered genes or pathways evaluated, including but not limited to Tumor Mutational Burden, EGFR, RB1, TP53, FUBP1, NF 1 or 2, PTEN, PDGFRA, PIK3CA, PIK3R1, CDK4, KRAS, MLH1, MLH2, MSH6 genomic alterations or CDKN2A/B homozygous deletion (all p&gt;0.05). Conclusions: Pembrolizumab shows limited overall efficacy in recurrent gliomas, however, exploratory analyses identified several subtype-specific genomic alterations that may correlate with PFS. These hypothesis-generating findings highlight the potential influence of underlying tumor biology on immunotherapy response and warrant further validation in larger, prospective cohorts. Citation Format: Shameel Shafqat, Muhammad Asad Maqbool, Hussam Al Kateb, Terry C. Burns, Jian L. Campian, Shannon P. Fortin Ensign, Evanthia Galanis, Julie E. Hammack, Cristaine M. Ida, Mitch L. Klebig, Timothy J. Kaufmann, Autumn C. Moon, Maciej M. Mrugala, Bryan J. Neth, Alyx B. aPorter, Michael W. Ruff, Ugur T. Sener, Wendy J. Sherman, Joon H. Uhm, Rachael A. Vaubel, Sani H. Kizilbash. Molecular correlates of progression-free survival in recurrent gliomas treated with pembrolizumab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5253.

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 Background DNA methylation profiling can be used to robustly predict postsurgical outcomes and response to radiotherapy (RT) for meningioma patients. To allow for seamless integration of these complementary models into clinical practice, a practical framework is needed. Methods We leveraged a cohort of nearly 2000 surgically-treated meningiomas with DNA methylation profiling and clinical outcomes data. Existing methylation-based prediction models were dichotomized to yield four risk groups: low and high recurrent risk, each with RT sensitive and resistant subgroups. Risk groups were correlated with progression-free survival in the context of existing biomarkers including extent of resection and WHO grade. Results We first demonstrated that all risk groups benefit from gross total resection. All “high-risk, RT sensitive” tumors (n = 306, 15.7%) also benefited from adjuvant RT: after GTR, median PFS increased from 4.68 (4.13-9.48) years to not reached (P = .003); after subtotal resection (STR), from 2.12 (1.59-3.02) to 4.09 (3.41-not reached) years (P = .004). “Low-risk, RT sensitive cases” (n = 1207, 61.8%) also benefited from RT after STR (median PFS 7.39 (6.66-12.8) vs. 16.53 (10.35-not reached) years, P = .03), suggesting that RT be considered in these patients. Neither “low-risk RT resistant” (n = 84, 4.3%) nor “high-risk RT resistant” (n = 356, 18.2%) cases benefited from RT, and the latter group was associated with universally poor outcomes. Conclusions We identify methylation-defined risk groups of meningioma for which additional benefit is gained from adjuvant RT, leading to a clinical decision-making framework for straightforward integration of molecular models into clinical practice.