Hearing Outcomes After Stereotactic Radiosurgery for Unilateral Intracanalicular Vestibular Schwannomas: Implication of Transient Volume Expansion
- Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam-si (Korea, Republic of)
- Department of Neurosurgery, Seoul National University Hospital, Seoul (Korea, Republic of)
Purpose: We evaluated the prognostic factors for hearing outcomes after stereotactic radiosurgery (SRS) for unilateral sporadic intracanalicular vestibular schwannomas (IC-VSs) as a clinical homogeneous group of VSs. Methods and Materials: Sixty consecutive patients with unilateral sporadic IC-VSs, defined as tumors in the internal acoustic canal, and serviceable hearing (Gardner-Roberson grade 1 or 2) were treated with SRS as an initial treatment. The mean tumor volume was 0.34 {+-} 0.03 cm{sup 3} (range, 0.03-1.00 cm{sup 3}), and the mean marginal dose was 12.2 {+-} 0.1 Gy (range, 11.5-13.0 Gy). The median follow-up duration was 62 months (range, 36-141 months). Results: The actuarial rates of serviceable hearing preservation were 70%, 63%, and 55% at 1, 2, and 5 years after SRS, respectively. In multivariate analysis, transient volume expansion of {>=}20% from initial tumor size was a statistically significant risk factor for loss of serviceable hearing and hearing deterioration (increase of pure tone average {>=}20 dB) (odds ratio = 7.638; 95% confidence interval, 2.317-25.181; P=.001 and odds ratio = 3.507; 95% confidence interval, 1.228-10.018; P=.019, respectively). The cochlear radiation dose did not reach statistical significance. Conclusions: Transient volume expansion after SRS for VSs seems to be correlated with hearing deterioration when defined properly in a clinically homogeneous group of patients.
- OSTI ID:
- 22149705
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 1 Vol. 85; ISSN IOBPD3; ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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