Q: What is vestibular schwannoma, and how often do you see patients with this condition?
A: Vestibular schwannomas are benign, often slow-growing tumors of the nerve that connects the ear and the brain, which can affect hearing and balance. They come in various sizes and shapes, categorized based on their location within the internal auditory canal. Sizes range from small (less than 1 centimeter), medium (1 to 2.5 centimeters), large (2.5 to 4 centimeters), and giant (greater than 4 centimeters). In general, these tumors generally grow at a rate of 1 to 2 millimeters per year, with some remaining dormant for years and others occasionally forming cysts.
Overall, vestibular schwannoma is a rare condition, typically showing up in one case per 500 people. But they are the most common types of tumors in the cerebellopontine angle in adults.
Q: Why is it sometimes challenging for patients to get an accurate, timely diagnosis?
A: It sounds basic, but getting the right test is crucial. Patients with vestibular schwannoma often have hearing loss, tinnitus, dizziness or vertigo. If providers see these symptoms, I recommend starting with an audiogram. If the audiogram shows some asymmetry with the sensorineural component or a sensorineural type of hearing loss, such as a greater than a 10-decibel difference at two or more contiguous frequencies, or if there is a greater than 15-decibel difference at a single frequency, I’d then recommend patients get an MRI. I might also recommend an MRI if the patient has asymmetric or unilateral tinnitus or sudden sensorineural hearing loss.
Q: Once you’re able provide a differential diagnosis, what treatment methods might you employ?
A: Overall, there are three treatment strategies we use. First, there’s the wait-and-see approach, which we use in conjunction with serial imaging. If the tumor is small and there are few symptoms, it might be best to watch in this way it over time. The second option is surgical removal. The third option is to treat the tumor with a small, precise amount of radiation to stop its growth.
There’s no one-size-fits-all approach to treat vestibular schwannoma because those tumors can behave in an unpredictable manner. At RUSH, we base our treatment on the size of the tumor, the age of the patient and the patient’s preference for treatment. We’ll also consider factors related to the patient’s other health issues and quality of life before we consider surgery or radiation. These factors include how well the patient can hear, where the tumor’s located, and if the patient has any dizziness.
Q: If the patient is a good candidate for surgery, what are some considerations you have when performing it?
A: I would pay attention to two main things: 1) the size and location of the tumor; and 2) the age and overall health of the patient.
If we’re doing surgery, our primary goal is removing the tumor. We also want to preserve the patient’s hearing and facial nerve function. If a total resection could potentially compromise hearing or nerve function, then we typically leave a small amount of the tumor behind. If we remove the gross total or near-total amount of the tumor, it’s unlikely that the tumor will recur.
In cases where we only remove a subtotal of the patient’s tumor, there’s approximately a 30% chance that the tumor will start growing again. In that case, we’ll continue regular surveillance to make sure that isn’t the case. We’ll start out with imaging every six months, then once we’re convinced that the tumor is no longer growing, we may spread the imaging out over a longer period of time.
Q: How has the management of vestibular schwannoma changed over time?
A: Over the past few decades, there’s been a shift towards more conservative management of vestibular schwannoma. Physicians are prioritizing patients’ long-term neurological function versus trying to cure the condition. For instance, we may only do a subtotal removal of the patient’s tumor to protect surrounding nerves, then follow up with regular imaging.
Because of the location of the tumor, it takes a true multidisciplinary approach to appropriately treat the condition. At RUSH, we bring together clinicians in neurosurgery, neurotology, neuro-oncology, radiation oncology, neuroradiology, audiology and physical therapy who help patients achieve their best possible outcome.
