Parney, Ian

Abstract BACKGROUND Awake craniotomy with speech mapping remains a gold standard for achieving maximal safe resection of diffuse gliomas located in eloquent cortex. Significant practice variability exists with regards to patient selection, speech mapping paradigms, aggressiveness of resection, and use of other adjuncts. We report our experience with speech mapping procedures for patients with diffuse gliomas, comparing cases performed with and without intraoperative MRI. METHODS A single-surgeon retrospective review of 148 consecutive awake craniotomy procedures, from 2008-2024, was performed. We recorded baseline patient characteristics, speech mapping findings, post-operative course, and volumetric extents of resection. Multivariate regression analyses were performed for factors predictive of permanent aphasia and residual tumor volume. RESULTS Speech mapping was performed in 95% of cases, with positive speech areas found in 49% of cases. Intraoperative MRI cases (75% of total) had significantly greater extent of resection (87.4% vs. 78.6%, p=0.03) despite equivalent pre-operative volumes. Post-operative new/worsened aphasia was 15% for mild and 5% for moderate symptoms, and this was associated with reduced rates of return to work (54% vs 78%, p=0.04). Predictors of recovery from aphasia were extent of resection (OR 1.1, p=0.006) and 90-day disease progression (OR 0.06, p=0.04). Predictors of residual tumor volume were pre-operative tumor volume (β 0.3, p<0.001), identification of after-discharge potentials during speech mapping (β -9.7, p<0.001), and pre-operative functional status (β -0.3, p=0.02). Overall survival was impacted by presence of contrast enhancement (p=0.0002), tissue diagnosis (p<0.0001), and WHO grade (p<0.0001). CONCLUSIONS Awake craniotomy with speech mapping remains a valuable strategy for achieving maximal safe resection of diffuse gliomas, with the majority of patients returning to baseline level of functioning. New/worsened aphasia is the biggest risk of surgery, which significantly impacts patient quality of life. Intraoperative MRI can be considered as an adjunctive tool for awake speech mapping during glioma surgery.

Abstract BACKGROUND CNS ependymal tumors rarely demonstrate mixed subependymal and ependymal pathology. The clinical course of these tumors is difficult to predict, but prior studies have identified TERT mutations and loss of chromosome 6 as poor prognostic factors in these tumors when located in the posterior fossa. METHODS In this retrospective single-institution study, patients with a diagnosis of mixed subependymoma/ependymoma were identified and chart reviewed to describe demographics, pathological findings, treatment courses and clinical outcomes. RESULTS Eleven patients (median age 57, 2 female, 9 male) were identified. Ten tumors were in the posterior fossa and 1 in the cervical spine. At diagnosis, 2 underwent gross total resection, 8 underwent subtotal resection, and 1 was only biopsied. Radiotherapy was administered to 5 patients at initial diagnosis (54Gy in 30 fractions). Systemic therapy (temozolomide and bevacizumab) was administered at recurrence to 2 patients. Loss of chromosome 6 was present in 5 /11 patients and TERT mutations were present in 4/11 patients, with both present in 3/11 patients. Median progression-free survival (mPFS) was 90.1 months (95% CI: 90.1–NA), with 3 progression events observed at 22, 90, and 107 months. Median follow-up duration was 27.9 months. Receiving radiotherapy had a longer mPFS (98 vs 22 months, p=0.15), although non-significant. At the time of data cut-off none of the patients were deceased. CONCLUSIONS Mixed subependymoma/ependymoma is a rare diagnosis with varying clinical outcomes. Our case series demonstrated that the majority of patients did not exhibit the previously identified poor prognostic factors. Although non-significant due to limited case numbers, radiotherapy was suggestive of longer mPFS.

Abstract BACKGROUND High grade astrocytoma with piloid features (HGAP) is a newly recognized tumor with a distinct DNA methylation profile. Its clinical course, treatment response, and outcomes remain poorly understood. METHODS We conducted a retrospective cohort study across three Mayo Clinic sites including adults with a HGAP diagnosis confirmed by DNA methylation profiling. RESULTS 17 patients were included (median age 38 years, Q1, Q3: 29–59; 9 male). DNA methylation-based tumor classification using the NCI/Bethesda classifier (v2) indicated a match to HGAP with high confidence (calibrated score >0.9) in 14 cases and was suggestive in 3 cases. All had MAPK pathway alterations (NF-1 mutation in 11, FGFR1 mutation in 2, KIAA1549::BRAF fusion in 2, FGFR1 transcript variant suggestive of internal tandem duplication in 1, KANK2::NTRK2 fusion in 1). All tumors also had CDKN2A/B homozygous deletion and 9 lost ATRX expression. Tumors were infratentorial (n=8), supratentorial (n=7), and spinal (n=2) at initial presentation. First line treatment included surgery followed by chemoradiation with temozolomide (n=12), surgery followed by radiation (n=4), radiation alone (n=1), and surgery alone (n=1). Gross total resection was achieved in 3/17, 8/17 had subtotal resection and 5/17 had biopsy. 14/17 received a median RT dose of 5700 cGy (range, 4005–6000) in 30 fractions. The median follow-up duration was 34.9 months. 8 patients experienced disease progression. The median progression-free survival (mPFS) was 30.3 months (95% CI: 15.4–NR). 6/8 underwent surgery; 3/8 underwent RT. Systemic therapies were administered in 5/8 (lomustine, bevacizumab, pembrolizumab, temozolomide, trametinib, tovorafenib). 3/17 patients died due to progressive disease with an OS of 54.2, 94.6 and 17.4 months, respectively. The mOS for the whole cohort was 54.2 months (95% CI: 54.2-NR). CONCLUSION While the optimal management of this newly recognized entity has yet to be established, our cohort demonstrates a clinical behavior consistent with CNS WHO grade 3, aligning with current WHO interpretations.

Abstract OBJECTIVE Despite advancements in therapy and improved survival rates for patients with primary central nervous system lymphoma (PCNSL), the optimal management strategy for recurrent or refractory PCNSL (r/r PCNSL) remains undefined. In such cases, repeat brain biopsy is often performed to confirm disease recurrence, though its diagnostic and therapeutic value is uncertain. This study evaluates whether repeat brain biopsy provides new, actionable diagnostic insights that influence treatment decisions. METHODS A retrospective analysis was conducted on patients with a confirmed diagnosis of PCNSL who underwent repeat brain biopsy for suspected recurrent or refractory disease between 2005 and 2023. Patients with a history of other CNS neoplasms, demyelinating disorders, or active systemic disease were excluded. RESULTS Twenty patients met inclusion criteria (55% female), with a mean age at biopsy of 56 years in the PCNSL group and 61 years in the r/r PCNSL group. While the overall distribution of presenting symptoms did not significantly differ (p = 0.2), gait instability, weakness, and cognitive decline were more common in r/r PCNSL. PCNSL more often presented with single lesions, while r/r PCNSL had predominantly multiple lesions (p < 0.05). Periventricular enhancement was significantly more frequent in r/r PCNSL (p < 0.05), though other radiologic features were comparable. Repeat biopsy confirmed DLBCL in 90% of cases; no infections or alternate malignancies were identified. Diagnostic clarification was the primary indication for repeat biopsy. Chemotherapy regimens were altered in 50% of post-biopsy cases, without a corresponding difference in overall survival (p = 0.79). Procedure-related morbidity was observed in three patients (15%). CONCLUSIONS The second biopsy in most cases reaffirmed the original diagnosis of diffuse large B cell lymphoma. Although biopsy results led to treatment adjustments; these changes did not affect overall survival.

Abstract While serial sampling of glioma tissue is rarely performed before recurrence, cerebrospinal fluid (CSF) can be acquired serially to evaluate candidate monitoring and pharmacodynamic biomarkers in patients with gliomas. However, the impact of key variables to consider in longitudinal CSF, including anatomical location and post-surgical changes, remains unknown. To that end, pre- versus post-resection intracranial CSF samples from patients with gliomas were obtained at early (1-16 days; n=20) or delayed (86-153 days; n=11) timepoints, as well as lumbar-versus-intracranial glioma CSF samples (n=14). Using aptamer-based proteomics, we identified significant differences in the glioma CSF proteome between lumbar, subarachnoid, and ventricular CSF. Indeed, intracranial CSF in paired lumbar/intracranial samples had nearly 1600 unique aptamers, regardless of which intracranial location was compared to the paired lumbar CSF, including in enrichment style analyses that evaluated the overlap between protein states. Importantly, resection had a significant, evolving longitudinal impact on the CSF proteome, with subsets of proteins associated with early versus delayed post-resection changes, many of which were enriched for inflammatory-related pathways. Interestingly, despite increased contamination from surgical debris, enrichment for plasma-associated proteins decreased with resection (FDR: 0.000), suggesting that a portion of the baseline glioma panel could be derived from plasma-originating analytes due to blood-brain barrier disruption. Despite these challenges, our data still revealed preliminary candidate monitoring biomarkers, such as brevican, that increased with progression (example patient: fold-change of 3.58x and 2.08x through lomustine and bevacizumab, respectively), but not pseudoprogression (Fold change less than 1.5). Serial intracranial CSF samples suggested the early potential for disease monitoring and evaluation of pharmacodynamic impact of targeted therapies, including bevacizumab and pembrolizumab. In conclusion, our available data to date suggest that the intracranial glioma CSF proteome provides an abundant and evolving source of candidate biomarkers to longitudinally discern the impact of resection and systemic treatments.

Abstract Genomic alterations and molecular subgroups between extracranial disease sites and brain metastases often differ, yet the prevalence and clinical significance of divergent evolution in brain metastases is not fully understood. This study examined genomic alterations and molecular subgroup divergence rates between matched brain metastases and extracranial disease sites. A retrospective, two-center study was conducted on patients who underwent resection of brain metastases between 2014-2022 with clinical and matched genomic data and/or molecular markers available. The overall cohort comprised 256 patients with matched tumors from multiple cancer types, most commonly from breast (n=108, 42.2%), melanoma (n=83, 32.4%), and NSCLC (n=43, 16.8%). Targeted next-generation sequencing of over 500 oncogenes was performed on resected tumors as part of clinical care (n=41 patients with matched specimens). Molecular subgroups for breast, melanoma, and non-small cell lung cancer were also assessed by immunohistochemistry to evaluate rates of molecular subgroup discordance between sites. Subgroup discordance by immunohistochemistry was observed most frequently across breast cancer (22.2%, n=24/108) with loss of the estrogen receptor (ER) and progesterone receptor (PR) and gain of HER2 most frequently observed within brain metastases. Molecular subgroup discordance was rare within melanoma (7.3%, n=6/82) and NSCLC (14.0%, n=6/43) patients. When evaluating oncogenomic alterations from targeted DNA sequencing in 41 patients with matched specimens, 80.5% (33/41) of brain metastases demonstrated a unique oncogene alteration profile compared to an extracranial disease site. Fourteen patients (34.1%) had a gain of at least 1 targetable alteration within a brain metastasis that was not observed in an extracranial disease site. Brain metastases demonstrated high rates of genomic divergence compared to primary and extracranial metastatic disease sites. This data supports obtaining brain metastasis tissue and conducting molecular profiling of this tissue to help select optimal CNS penetrant systemic therapies for each patient.

AbstractBackgroundGlioblastoma (GBM) represents an aggressive cancer type with a median survival of only 14 months. With fewer than 5% of patients surviving 5 years, comprehensive profiling of these rare patients could elucidate prognostic biomarkers that may confer better patient outcomes. We utilized multiple molecular approaches to characterize the largest patient cohort of isocitrate dehydrogenase (IDH)–wildtype GBM long-term survivors (LTS) to date.MethodsRetrospective analysis was performed on 49 archived formalin-fixed paraffin embedded tumor specimens from patients diagnosed with GBM at the Mayo Clinic between December 1995 and September 2013. These patient samples were subdivided into 2 groups based on survival (12 LTS, 37 short-term survivors [STS]) and subsequently examined by mutation sequencing, copy number analysis, methylation profiling, and gene expression.ResultsOf the 49 patients analyzed in this study, LTS were younger at diagnosis (P = 0.016), more likely to be female (P = 0.048), and MGMT promoter methylated (UniD, P = 0.01). IDH-wildtype STS and LTS demonstrated classic GBM mutations and copy number changes. Pathway analysis of differentially expressed genes showed LTS enrichment for sphingomyelin metabolism, which has been linked to decreased GBM growth, invasion, and angiogenesis. STS were enriched for DNA repair and cell cycle control networks.ConclusionsWhile our findings largely report remarkable similarity between these LTS and more typical STS, unique attributes were observed in regard to altered gene expression and pathway enrichment. These attributes may be valuable prognostic markers and are worth further examination. Importantly, this study also underscores the limitations of existing biomarkers and classification methods in predicting patient prognosis.