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Updated: Nov 2, 2025
A Unified Methodological Framework for Vestibular Schwannoma Research
Published on: June 20, 2017
Natural History of Growing Sporadic Vestibular Schwannomas During Observation: An International Multi-Institutional
John P Marinelli1,2, Matthew L Carlson2,3, Jacob B Hunter4
1Department of Otolaryngology-Head and Neck Surgery, San Antonio Uniformed Services Health Education Consortium, San Antonio, Texas.
Objective:
Active treatment of small- or medium-sized vestibular schwannoma during wait-and-scan management is currently recommended at most centers globally once growth is detected. The primary aim of the current study was to characterize the natural history of growing sporadic vestibular schwannoma during observation.
Study Design:
Cohort study.
Setting:
Four tertiary referral centers across the United States and Denmark.
Patients:
Patients with two prior MRI scans demonstrating ≥2 mm of linear growth who continued observational management.
Intervention:
Observation with serial imaging.
Main Outcome Measure:
Subsequent linear growth-free survival (i.e., an additional ≥2 mm of growth) following initial growth of ≥2 mm from tumor size at diagnosis.
Results:
Among 3,402 patients undergoing observation, 592 met inclusion criteria. Median age at initial growth was 66 years (IQR 59-73) for intracanalicular tumors (N = 65) and 62 years (IQR 54-70) for tumors with cerebellopontine angle extension (N = 527). The median duration of MRI surveillance following initial detection of tumor growth was 5.2 years (IQR 2.4-6.9) for intracanalicular tumors and 1.0 year (IQR 1.0-3.3) for cerebellopontine angle tumors. For intracanalicular tumors, subsequent growth-free survival rates (95% CI; number still at risk) at 1, 2, 3, 4, and 5 years following the initial MRI that demonstrated growth were 77% (67-88; 49), 53% (42-67; 31), 46% (35-60; 23), 34% (24-49; 17), and 32% (22-47; 13), respectively. For cerebellopontine angle tumors, subsequent growth-free survival rates were 72% (68-76; 450), 47% (42-52; 258), 32% (28-38; 139), 26% (21-31; 82), and 22% (18-28; 57), respectively. For every 1 mm increase in magnitude of growth from diagnosis to tumor size at detection of initial growth, the HRs associated with subsequent growth were 1.64 (95% CI 1.25-2.15; p < 0.001) for intracanalicular tumors and 1.08 (95% CI 1.01-1.15; p = 0.02) for cerebellopontine angle tumors.
Conclusions:
Growth detected during observation does not necessarily portend future growth, especially for slowly growing tumors. Because early treatment does not confer improved long-term quality of life outcomes, toleration of some growth during observation is justifiable in appropriately selected cases.
Insights
Growth in vestibular schwannoma during observation doesn't always predict future growth. Tolerating some tumor growth may be acceptable, as early treatment doesn't improve long-term quality of life.
Area of Science:
- Neurosurgery
- Oncology
- Radiology
Background:
- Vestibular schwannoma (VS) management often involves observation with serial imaging.
- Active treatment is typically recommended upon detecting tumor growth during observation.
- The natural history of growing VS under continued observation requires further characterization.
Purpose of the Study:
- To characterize the natural history of growing sporadic vestibular schwannoma (VS) during observation.
- To assess subsequent growth-free survival rates in patients with initially growing VS who continued observation.
- To identify factors influencing tumor regrowth after initial growth detection.
Main Methods:
- Retrospective cohort study involving 592 patients with growing VS from four international centers.
- Patients had demonstrated ≥2 mm linear growth on two prior MRI scans and continued observational management.
- Subsequent linear growth-free survival was analyzed using Kaplan-Meier methods, with Cox proportional hazards models assessing predictors of growth.
Main Results:
- Median age at initial growth was 66 years for intracanalicular tumors and 62 years for cerebellopontine angle (CPA) tumors.
- Five-year growth-free survival rates were 32% for intracanalicular and 22% for CPA tumors.
- Each 1 mm increase in growth magnitude from diagnosis to initial detection was associated with a 1.64 hazard ratio for subsequent growth in intracanalicular tumors and 1.08 in CPA tumors.
Conclusions:
- Tumor growth detected during observation does not invariably predict further growth, particularly for slowly progressing tumors.
- Continued observation may be justifiable for select patients with growing VS, as early intervention does not guarantee improved long-term quality of life.
- These findings support a more nuanced approach to VS management, balancing the risks of observation against the benefits of early treatment.
