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Small acoustic neuromas: monitoring the growth rate by MRI
G C Modugno1, A Pirodda, G G Ferri
1ENT Department, University of Bologna, Policlinico "S. Orsola-Malpighi", Bologna, Italy.
Abstract:
In a proportion of small acoustic neuroma patients, monitoring with magnetic resonance imaging shows no volumetric increase of tumour size over the years. The object of the study was to identify some indications for the clinical choice between immediate surgery (with the related risks) and watchful waiting. We performed a retrospective study of 47 non-surgically-treated patients affected by acoustic neuroma and monitored by gadolinium-enhanced MRI between January 1990 and February 1999. Six clinical variables (tumour size, sex, age, initial symptoms, ABR pattern and duration of the symptoms) were examined by univariate analysis. Chi-square test and variance analysis were performed to evaluate the statistical significance. In 30/47 (63.8%) cases, no growth was observed during the entire period of follow-up. In the remaining 17/47 (36.2%) patients, a volumetric increase was detected, most often within the first year of observation. The clinical factors examined did not significantly correlate with growth. Despite the relatively short period of observation, we believe that immediate surgery does not need to be considered mandatory for small acoustic neuromas, even in young patients. However the irregular behaviour of the tumour underlines the importance of monitoring with MRI at least once a year.
Insights
Many small acoustic neuromas do not grow, suggesting watchful waiting may be suitable. Regular MRI monitoring is crucial due to unpredictable tumor behavior in acoustic neuroma patients.
Area of Science:
- Neurosurgery
- Oncology
- Radiology
Background:
- Acoustic neuromas, benign tumors of the vestibulocochlear nerve, often present with slow growth.
- Management decisions for small acoustic neuromas involve balancing surgical risks with potential tumor progression.
- Magnetic resonance imaging (MRI) is the standard for monitoring tumor size and growth.
Purpose of the Study:
- To identify clinical indicators for choosing between immediate surgery and watchful waiting for small acoustic neuromas.
- To evaluate factors influencing tumor growth in non-surgically managed acoustic neuroma patients.
Main Methods:
- Retrospective analysis of 47 patients with acoustic neuroma treated non-surgically.
- Tumor size monitored via gadolinium-enhanced MRI between 1990 and 1999.
- Univariate analysis of six clinical variables: tumor size, sex, age, initial symptoms, auditory brainstem response (ABR) pattern, and symptom duration.
Main Results:
- No significant tumor growth observed in 63.8% (30/47) of patients during the follow-up period.
- Tumor volume increase detected in 36.2% (17/47) of patients, primarily within the first year.
- No statistically significant correlation found between examined clinical factors and tumor growth.
Conclusions:
- Immediate surgery may not be mandatory for small acoustic neuromas, even in younger patients, given the high proportion of non-growing tumors.
- The unpredictable growth pattern of acoustic neuromas necessitates annual MRI monitoring.
- Watchful waiting is a viable management option for select small acoustic neuroma cases.