Natural History of Vestibular Schwannoma Growth and Hearing Decline in Newly Diagnosed Neurofibromatosis Type 2 Patients
Objective To determine the rate of growth in vestibular schwannomas and the rate of hearing decline in neurofibromatosis type 2 (NF2) patients not undergoing active treatment Study Design Prospective study. Setting Data were collected at 10 NF2 centers, including hospital-based, academic, and tertiary care centers. Patients 120 NF2 patients with 200 vestibular schwannomas. Outcome Measures Hearing decline, defined as a decrease in word recognition score outside the 95% critical difference compared with baseline, and radiographic progression, defined as a 20% or greater increase in tumor volume compared with baseline. Results During a total of 313.4 patient-years of follow-up, the rate of hearing decline was 5% at 1 year, 13% at 2 years, and 16% at 3 years; the rate of tumor progression was 31% at 1 year, 64% at 2 years, and 79% at 3 years. For this cohort, the median time to tumor progression (14 mo) was significantly shorter than the median time to hearing decline (62.0 mo). Conclusion These data provide potentially useful information for the design of clinical trials for NF2 vestibular schwannoma.