Abstract
BACKGROUND: Vestibular schwannomas (VS) represent the fourth most common type of intracranial tumor. While the majority of these benign lesions are non-growing or slow-growing with the potential to be managed through active surveillance, a subset progress rapidly between scans, posing a substantial threat of neurologic morbidity. At present, patient demographic, clinical, and radiographic characteristics have failed to reliably identify these high-risk tumors. There is growing interest in the use of fluid-based biomarkers to predict tumor growth, hearing loss, and response to surgical or radiotherapeutic treatment. METHODS: We conducted a systematic review summarizing the current evidence for the utility of fluid-based biomarkers in predicting tumor progression and hearing outcomes in VS. Ovid MEDLINE, Embase, Web of Science, and Scopus were searched for primary source articles using keywords for fluid-based biomarkers and outcomes in adult (≥ 18 years) patients with de novo diagnoses of sporadic vestibular schwannoma. RESULTS: Ten studies conducted from 2011–2024 were included. Five studies measured biomarkers in blood, two in CSF, and two in perilymph. Three studies evaluated immune-related biomarkers, one analyzed protease enzymes, three performed proteomics, and a final study performed microRNA profiling. Perilymph AHSG and CFHR2, cerebrospinal fluid FN1 and fibrinogen, and plasma MMP-14, were identified as biomarkers of hearing loss. Blood neutrophil-to-lymphocyte ratio, serum TGF-β1 and CSF of ABCA3, KLF11, SCG1, BASP1, CA2D1 and PRDX2 were associated with tumor growth. CONCLUSION: Biomarkers involved in inflammation and extracellular matrix remodeling show promise for risk stratification in sporadic VS. More work is needed to validate these preliminary findings.