Incidental vestibular schwannomas: a review of prevalence, growth rate, and management challenges

Abstract

<jats:p>With the relatively recent increase in the use of MRI techniques, there has been a concurrent rise in the number of vestibular schwannomas (VSs) detected as incidental findings. These incidental VSs may be prevalent in up to 0.02%–0.07% of individuals undergoing MRI and represent a significant portion of all diagnosed VSs. The management of these lesions poses a significant challenge for practitioners. Most incidental VSs tend to be small and associated with minimal symptoms, permitting them to be managed conservatively at the time of diagnosis. However, relatively few indicators consistently predict tumor growth and patient outcomes. Furthermore, growth rates have been shown to vary significantly over time with a large variety of long-term growth patterns. Thus, early MRI screening for continued tumor growth followed by repeated MRI studies and clinical assessments throughout the patient's life is an essential component in a conservative management strategy. Note that tumor growth is typically associated with a worsening of symptoms in patients who undergo conservative management, and many of these symptoms have been shown to significantly impact the patient's quality of life. Specific indications for the termination of conservative management vary across studies, but secondary intervention has been shown to be a relatively safe option in most patients with progressive disease. Patients with incidental VSs will probably qualify for a course of conservative management at diagnosis, and regular imaging combined with the expectation that the tumor and symptoms may change at any interval is crucial to ensuring positive long-term outcomes in these patients. In this report, the authors discuss the current literature pertaining to the prevalence of incidental VSs and various considerations in the management of these lesions. It is hoped that by incorporating an understanding of tumor growth, patient outcomes, and management strategies, practitioners will be able to effectively address this challenging disease entity.</jats:p>

Long-term quality of life in patients with vestibular schwannoma: an international multicenter cross-sectional study comparing microsurgery, stereotactic radiosurgery, observation, and nontumor controls

“…2,9,26 With an increasing prevalence of small tumors in minimally symptomatic patients it is paramount that we carefully examine both traditional clinical measures and HRQOL data when determining best practices. 29,32 Previous studies evaluating HRQOL in VS have carried several notable limitations including low patient numbers, lack of a normal non-VS control population, exclusion of one or more treatment groups, and short-term follow-up and have therefore been criticized for being methodologically weak. 9 To date, only 3 prospective, nonrandomized studies have been published comparing HRQOL outcomes following treatment, and currently no Level 1 evidence exists.…”

“…3 Increasing patient access to MRI and the implementation of screening protocols for patients with asymmetrical hearing loss have led to a significant increase in the number of VSs diagnosed each year, with a higher proportion of patients presenting with small tumors and minimal symptoms. 29,32 Contemporary management strategies include microsurgical resection, stereotactic radiosurgery (SRS) or stereotactic radiotherapy, and observation with serial imaging. Owing to concurrent advancements in surgical technique and radiation delivery strategies, diseasespecific mortality now approaches zero and the majority of patients benefit from durable tumor control whether managed using SRS or microsurgery.…”

Vestibular Schwannoma Excision in Sporadic versus Neurofibromatosis Type 2 Populations

“…18 A previous study showed that the mean tumor size at diagnosis registered in a national database decreased from 30 mm in 1976 to 10 mm in 2008. 19 Paradoxically, our study found that the number of patients undergoing surgical resection for NF2 VS cases has decreased from 1997 to 2011.…”

MRI surveillance of vestibular schwannomas without contrast enhancement: Clinical and economic evaluation

“…Vestibular schwannomas (VS), also known as acoustic neuromas, are benign, typically slow‐growing, and most commonly occurring in the cerebellopontine angle (CPA) and internal auditory canal (IAC) . These neoplasms originate from the Schwann cells of the vestibulocochlear nerve sheath and account for 6% of all intracranial tumors, 10% of all brain neoplasms, and approximately 80% to 85% of all CPA tumors . Several studies have approximated the incidence of VS at 10 to 20 cases per million people per year, although postmortem temporal bone dissections have shown these rates to be much higher—presumably due to incidental identification of clinically silent lesions .…”