From the Guidelines
For patients with acoustic neuroma, stereotactic radiosurgery (SRS) is the recommended treatment option, as it offers equivalent rates of tumor control and hearing preservation compared to microsurgical resection, with better facial nerve preservation. This is based on the most recent and highest quality study available, which compared treatment outcomes amongst management strategies for intracanalicular vestibular schwannomas 1. The study found that SRS had a weighted pooled estimate for tumor control of 96%, compared to 65% for conservative surveillance and 92% for microsurgical resection. Additionally, SRS had a lower rate of persistent facial nerve deficit, at 0.1%, compared to 10% for microsurgical resection.
Key Considerations
- Tumor size and symptoms play a crucial role in determining the treatment approach, with larger tumors often requiring surgical intervention to reduce mass effect 1.
- Hearing preservation is a key consideration in the treatment of acoustic neuroma, and SRS has been shown to have similar rates of hearing preservation compared to microsurgical resection 1.
- Patient factors, including age, overall health, and personal preferences, should be taken into account when determining the best course of treatment, ideally with a multidisciplinary team including neurosurgeons, otolaryngologists, and radiation oncologists.
Treatment Options
- Stereotactic radiosurgery (SRS): a non-invasive treatment option that offers equivalent rates of tumor control and hearing preservation compared to microsurgical resection, with better facial nerve preservation 1.
- Microsurgical resection: a surgical approach that may be necessary for larger tumors or those causing significant symptoms, but carries a higher risk of facial nerve deficit 1.
- Conservative surveillance: a watchful waiting approach that may be suitable for small, asymptomatic tumors, but carries a higher risk of tumor growth and need for additional treatment 1.
From the Research
Definition and Diagnosis of Acoustic Neuroma
- Acoustic neuroma, also known as vestibular schwannoma, is a benign intracranial tumor composed of Schwann cells that typically involves the vestibular division of the 8th cranial nerve 2.
- The diagnosis of acoustic neuroma has evolved over time, with modern techniques such as audiometry with acoustic reflex testing, brain stem evoked responses, and computed tomography (CT) replacing older tests like cerebrospinal fluid protein, vestibular testing, and arteriography 3.
Treatment Options for Acoustic Neuroma
- Surgery is the mainstay of treatment for acoustic neuroma, but stereotactic radiosurgery and radiotherapy have emerged as alternative viable options 4.
- The choice of treatment depends on factors such as age, tumor size, symptoms, and residual hearing, with conservative management often used for patients over 65 years of age 5.
- Stereotactic radiosurgery using either a cobalt unit or a linear accelerator has given high rates of tumor control and cranial nerve function preservation, with marginal doses ranging from 12-14 Gy 4, 6.
- Fractionated stereotactic radiotherapy (FSRT) is optimal for tumors larger than 3 cm, with doses as low as 50.4 Gy providing excellent control rates and low morbidity 4.
Outcomes and Complications of Treatment
- Clinical tumor control rates after stereotactic radiosurgery are high, with rates of 98%, 89%, and 88% at 2,5, and 10 years, respectively 6.
- Hearing preservation rates are also considerable, with objective actuarial hearing preservation rates of 89%, 80%, and 55% at 1,2, and 5 years, respectively 6.
- New symptoms are observed in a small percentage of patients, with most being classified as mild (Common Terminology Criteria for Adverse Events grade 1/2) 6.