Neurosurgery — Weekly Evidence Brief

Advances in the management and understanding of brain metastases (BM) continue to refine clinical practice. Colorectal cancer patients with isolated BM, for instance, showed a median overall survival of 23.26 months when treated with stereotactic radiosurgery combined with systemic therapy, significantly longer than the overall median survival of 7.82 months for this group 1. For patients with EGFR-mutated non-small cell lung cancer, central nervous system metastases are common, and third-generation EGFR-targeted tyrosine kinase inhibitors demonstrate efficacy, especially when integrated with chemotherapy or radiation for resistant lesions 2. Importantly, differentiation between pseudoprogression and true progression after immune-checkpoint inhibitor (ICI) therapy for brain metastases is critical; pseudoprogression, occurring in 17.3% of patients, is uniquely characterized by not requiring dexamethasone for neurological symptoms, unlike true progression 3. Genomic analyses are further informing prognosis, with higher tumor mutation burden and specific mutations like PTPRT associated with better outcomes and improved immunotherapy response in brain metastasis patients 4.

Diagnostic imaging continues to evolve, offering improved detection and differentiation of brain lesions. Deep learning-based image enhancement significantly boosts sensitivity for detecting brain metastases, notably improving detection of lesions smaller than 5mm from 69% to 78%, without compromising specificity or increasing false positives 5. For suspected recurrence of lung cancer brain metastases after stereotactic radiosurgery, [18F]F-fluorocholine PET/CT demonstrates higher specificity and accuracy than contrast-enhanced MRI, with combined modality imaging offering the best diagnostic performance 6. Furthermore, explainable AI models can accurately classify neoplastic intracerebral hemorrhage from non-contrast CT images, potentially streamlining early diagnostic pathways 7. In a pediatric case, cerebrospinal fluid liquid biopsy successfully provided molecular classification of a secondary glioma, distinguishing it from a medulloblastoma relapse and facilitating timely enrollment in a targeted therapy trial 8.

Management strategies for specific brain tumors are being clarified with new evidence. For craniopharyngioma, a meta-analysis of the endoscopic endonasal approach demonstrated that gross total resection (GTR) significantly reduced recurrence rates to 10%, compared to 30% for subtotal resection combined with radiotherapy 9. Diffuse leptomeningeal glioneuronal tumors (DLGNTs), rare but significant in young patients, are highly associated with KIAA1549::BRAF fusions (96.4%) and carry a poor prognosis, with 5-year progression-free survival at 15.9% 10. Prognostic factors for DLGNT include age at diagnosis and the DLGNT MC-2 methylation subclass, which is linked to worse 5-year overall survival 10.

Advances in endovascular therapies are optimizing outcomes for acute ischemic stroke patients. For large ischemic strokes, achieving expanded Thrombolysis in Cerebral Infarction (eTICI) grades 2c-3 during endovascular treatment is significantly associated with higher odds of improved functional outcomes (mRS 0-3) and lower mortality compared to lower recanalization grades 11. While very elderly patients (≥90 years) undergoing endovascular therapy for ischemic stroke have higher rates of poor functional outcomes, mortality, and unsuccessful recanalization than younger patients, the probability of symptomatic intracranial hemorrhage is not increased, suggesting age alone should not preclude treatment consideration 12. Furthermore, in distal-medium vessel occlusion, CT-perfusion target mismatch criteria (core volume ≤30 mL, penumbra volume ≥10 mL, mismatch ratio ≥1.2) are independently associated with better functional outcomes after endovascular treatment 13.