From the Guidelines
The percentage of coincidental vestibular schwannoma that enlarge on follow-up is approximately 7.2% after a stable period of 5 years following diagnosis, as reported in a large prospectively followed cohort of extra- and intracanalicular tumors 1.
Key Points to Consider
- The growth rate of vestibular schwannomas is typically slow, at 1-2 mm per year, though this varies considerably with some tumors showing no growth while others grow more rapidly.
- For small tumors (<2 cm) without significant symptoms, observation with regular MRI monitoring every 6-12 months is often recommended initially.
- Treatment options for growing tumors or those causing progressive symptoms include microsurgery, stereotactic radiosurgery (such as Gamma Knife), or fractionated radiotherapy.
- The choice between observation and intervention should be individualized based on tumor size, location, growth rate, patient age, hearing status, and other symptoms.
- Regular follow-up is essential regardless of the management approach chosen, with annual MRI follow-up recommended for 5 years in patients with untreated tumors, and follow-up intervals can be prolonged thereafter if the tumor remains stable 1.
Management Approach
- Stereotactic radiosurgery (SRS) is a noninvasive treatment with at least equivalent rates of tumor control and hearing preservation as compared to microsurgical resection, with better facial nerve preservation 1.
- Upfront SRS is an effective treatment in achieving tumor control with similar rates of hearing preservation as compared to conservative surveillance (CS) 1.
- CS should be considered as the recommended approach for older patients and no appreciable tumor growth regardless of hearing status 1.
Important Considerations
- Patients should understand that even with treatment, hearing preservation is not guaranteed, and potential complications include facial nerve dysfunction, balance problems, and headaches.
- The management of vestibular schwannomas requires a multidisciplinary approach, taking into account the patient's individual characteristics, tumor size, and growth rate.
From the Research
Growth Rate of Vestibular Schwannomas
- The growth rate of vestibular schwannomas can vary, and there is no consensus on the exact percentage of coincidental vestibular schwannomas that enlarge on follow-up 2.
- However, it is recommended to obtain MRIs annually for 5 years, with interval lengthening thereafter with tumor stability 2.
- Cystic vestibular schwannomas may behave differently than their solid counterparts, with a higher risk of rapid growth and lower rates of complete resection 2.
Management Plan for Vestibular Schwannomas
- The management plan for vestibular schwannomas depends on various factors, including tumor size, location, symptoms, and patient preferences 3, 4.
- Treatment options include observation with serial imaging, stereotactic radiation, and microsurgical removal 3, 5.
- Surgical approaches, such as translabyrinthine, retrosigmoid, and middle fossa, have their advantages and disadvantages, and the goal of surgery is complete eradication of tumor with preservation of hearing and facial nerve function when possible 5.
- Exclusive surgical treatment for vestibular schwannoma residuals has a very low failure rate in terms of requiring further treatment, and the choice of surgical approach does not influence facial nerve function 6.
Follow-up and Imaging
- Postoperative evaluation should be performed with postcontrast 3-D T1 MPRAGE, with nodular enhancement considered suspicious for recurrence 2.
- Imaging follow-up should be adjusted accordingly for continued surveillance if any change in nodular enhancement is demonstrated 2.
- For patients receiving gross total resection, a postoperative MRI may be considered to document the surgical impression and may occur as late as 1 year after surgery 2.
- For patients not receiving gross total resection, more frequent surveillance scans are suggested, with annual MRI scans may be reasonable for 5 years 2.