You, Hyo Bin

OBJECTIVE Maximal safe resection of intra-axial brain tumors near the motor cortex is aided by intraoperative motor mapping. Here, the authors compared outcomes in patients undergoing either low-frequency bipolar stimulation (LFBS) or high-frequency monopolar stimulation (HFMS) for cortical and/or subcortical motor mapping during brain tumor resection. METHODS A retrospective analysis of patients undergoing an asleep craniotomy with motor mapping or an awake craniotomy with motor and speech mapping with a single surgeon was performed. Three cohorts were compared: 1) asleep LFBS (AsLFBS), 2) awake LFBS (AwLFBS; motor + speech mapping), and 3) asleep HFMS. HFMS mapping was not used for awake craniotomies. RESULTS A total of 284 patients who underwent 300 craniotomies with motor mapping were identified. No significant differences in permanent neurological deficits (p = 0.377) or extent of resection (EOR) of nonenhancing tumors (p = 0.453) were identified between LFBS or HFMS motor mapping cases. Both EOR (92.7% vs 83.5%, p = 0.035) and permanent neurological deficits (7.6% vs 3.3%) occurred more frequently in enhancing tumors with LFBS, although the latter was not statistically significant. HFMS was associated with higher rates of subcortical motor pathway identification (p = 0.001) and fewer total intraoperative seizures (p = 0.003) compared with LFBS. Previous resection (HR 0.46, p = 0.003) and a higher cortical threshold (HR 0.95, p = 0.023) were significantly associated with longer survival, while preoperative aphasia (HR 2.24, p = 0.022), hospital length of stay (HR 1.1, p = 0.005), an insular-based tumor (HR 3.5, p = 0.021), and a histological diagnosis of glioblastoma (HR 2.9, p = 0.001) were negative predictors. Interestingly, overall FLAIR EOR was significantly associated with a marginally decreased overall survival (HR 1.01, p = 0.011). CONCLUSIONS No significant differences in postoperative neurological deficits were found between LFBS and HFMS paradigms. HFMS may identify subcortical motor fibers more reliably while resulting in significantly fewer intraoperative seizures. Although LFBS was associated with greater EOR of contrast-enhancing tumors, it may also be associated with higher rates of postoperative deficits, perhaps reflecting less reliable identification of subcortical motor fibers.

OBJECTIVE Brain metastases significantly impact neurocognitive function and overall survival. Stereotactic radiosurgery (SRS) is a cornerstone of treatment for patients with limited metastases and expected survival beyond 3 months. Despite current guidelines, up to 20% of patients with brain metastases undergoing SRS have been reported to die within 90 days. This study retrospectively evaluated prognostic factors associated with 90-day survival after SRS, aiming to improve patient selection. METHODS The authors retrospectively analyzed a cohort of 1546 patients who underwent Gamma Knife SRS for brain metastases at their institution between 2015 and 2023. One hundred seventy patients who survived less than 90 days after SRS were identified and case matched to 170 patients who survived over 90 days. Measured variables included patient demographic characteristics, tumor characteristics, treatment history, functional status, and control of the primary cancer. The authors modeled post-SRS 90-day survival using binomial and multivariate logistic regression. RESULTS Multivariate analysis highlighted Karnofsky Performance Score (KPS) < 70 (OR 17.4, p < 0.001), prior whole-brain radiation (OR 6, p = 0.004), and focal neurological deficits (OR 3.02, p = 0.003) as significant predictors of poor survival, whereas CNS progression before SRS (OR 0.22, p < 0.001) and control of systemic cancer (OR 0.556, p = 0.002) were associated with survival < 90 days. The predictive model demonstrated acceptable performance with an area under the curve (AUC) of 0.85, accuracy of 80%, sensitivity of 87%, and specificity of 71%. CONCLUSIONS Key predictors of 90-day survival after SRS for brain metastases include functional status (KPS), control of systemic cancer, CNS progression status, and focal neurological deficits. These findings are complementary factors that can assist in making decisions and SRS patient selection.

Glioblastoma (GBM), the most common primary malignant brain tumor in adults, has a median survival of 14–15 months despite aggressive treatment. Monitoring relies on MRI, but differentiating tumor progression from pseudo-progression or radiation necrosis remains difficult. Plasma extracellular vesicles (EVs) are emerging as promising non-invasive biomarkers due to their molecular cargos and accessibility. This review evaluates studies that specifically isolated plasma EVs for molecular profiling in GBM diagnosis and monitoring. Biomarkers (miRNA, RNA, DNA, proteins), EV characterization methods, and advancements in enriching tumor-derived EV subpopulations and assessing their diagnostic and prognostic potential are highlighted. Plasma EVs carry diverse cargos, including miRNAs (e.g., miR-21, miR-15b-3p), mRNAs (e.g., EGFRvIII), circRNAs, and proteins (e.g., CD44, GFAP). Composite molecular signatures have achieved sensitivities of 87–100% and specificities of 73–100% for GBM diagnosis. Tumor-derived EVs, enriched using techniques like SEC-CD44 immunoprecipitation, microfluidic platforms, or 5-ALA-induced PpIX fluorescence, enhance biomarker detection. Non-tumor-derived EVs may also reflect GBM’s systemic effects. Challenges include EV heterogeneity, non-EV contamination, and variable biomarker expression across studies. Plasma-EV-based liquid biopsies offer significant potential for GBM monitoring, with advanced enrichment methods improving tumor-specific biomarker detection. Standardizing isolation protocols and validating biomarkers in larger cohorts are critical for clinical translation.

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 &lt; 0.05). Periventricular enhancement was significantly more frequent in r/r PCNSL (p &lt; 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 Brain metastases significantly impact neurocognitive function and overall survival. Stereotactic radiosurgery (SRS) is a cornerstone of treatment for patients with limited metastases and expected survival beyond three months. Despite current guidelines, up to 20% of patients with brain metastases undergoing SRS have been reported to die within 90 days. This study retrospectively evaluates prognostic factors associated with 90-day survival after SRS, aiming to improve patient selection. We retrospectively analyzed a cohort of 1,546 patients who underwent Gamma Knife SRS for brain metastases at our institution between 2015 and 2023. One hundred seventy patients who survived fewer than 90 days post-SRS were identified and case-matched to 170 patients who survived over 90 days. Measured variables included patient demographics, tumor characteristics, treatment history, functional status, and control of the primary cancer. We modeled post-SRS 90-day survival using binomial and multivariate logistic regression. Multivariate analysis highlighted Karnofsky Performance Status (KPS) &lt; 70 (OR: 17.4, p &lt; 0.001), prior whole brain radiation (OR: 6, p = 0.004), and focal neurological deficits (OR: 3.02, p = 0.003) as significant predictors of early deaths, while CNS progression before SRS (OR: 0.22, p &lt; 0.001) and control of systemic cancer (OR: 0.556, p = 0.002) were associated with a less than 90-day survival. The predictive model demonstrated acceptable performance with an area under the curve (AUC) of 0.85, accuracy of 80%, sensitivity of 87%, and specificity of 71%. Key predictors of 90-day survival following SRS for brain metastases include functional status (KPS), control of systemic cancer, CNS progression status, and focal neurologic deficits. These findings are complementary factors that can assist in making decisions and SRS patient selection.

Central nervous system (CNS) tumors are the leading cause of cancer-related mortality in children, with prognosis remaining dismal for some of these malignancies. Though the past two decades have seen advancements in surgery, radiation, and targeted therapy, major unresolved hurdles continue to undermine the therapeutic efficacy. These include challenges in suboptimal drug delivery through the blood–brain barrier (BBB), marked intra-tumoral molecular heterogeneity, and the elusive tumor microenvironment. Drug repurposing or re-tasking FDA-approved drugs with evidence of penetration into the CNS, using newer methods of intracranial drug delivery facilitating optimal drug exposure, has been an area of intense research. This could be a valuable tool, as most of these agents have already gone through the lengthy process of drug development and the evaluation of safety risks and the optimal pharmacokinetic profile. They can now be used and tested in clinics with an accelerated and different approach. Conclusions: The next-generation therapeutic strategy should prioritize repurposing oncologic and non-oncologic drugs that have been used for other indication, and have demonstrated robust preclinical activity against pediatric brain tumors. In combination with novel drug delivery techniques, these drugs could hold significant therapeutic promise in pediatric neurooncology.