Treatments: Acoustic Neuroma (Vestibular Schwannoma)
This page describes the treatment options for acoustic neuroma: watchful waiting, radiation and surgery.
Acoustic neuromas are benign and most grow slowly, so there is usually time to learn about the options and make a thoughtful decision; treatment is rarely an emergency. Background on the tumor itself, its symptoms and how it is diagnosed is on the acoustic neuroma conditions page.
The Three Main Approaches
There are three well-established ways to manage an acoustic neuroma:
Watchful waiting (also called "wait-and-scan" or observation)
Radiation, most often a focused, high-precision form called stereotactic radiosurgery
Surgery, meaning microsurgical removal of the tumor
For most small and medium-sized tumors, no single option has been proven clearly superior to the others. Each has its own balance of benefits and trade-offs, and the best fit depends heavily on the tumor's size, the person's hearing, age, other health conditions and personal preferences. For this reason, decisions are usually made with a team that may include an ear surgeon (neurotologist), a brain surgeon (neurosurgeon) and a radiation specialist. A second opinion from a center that treats many of these tumors is common and often encouraged.
Watchful Waiting (Wait-and-Scan)
Because many acoustic neuromas grow very slowly, often about 1 millimeter per year, or not at all, a common strategy is to monitor the tumor rather than treat it right away. Studies suggest that only roughly one-quarter to one-half of these tumors grow over several years of follow-up.
What this involves:
A repeat MRI, and often a hearing test, about 6 months after diagnosis to check for fast growth, then usually once a year, with longer intervals later if the tumor stays stable.
Lifelong monitoring, because growth can occasionally start after years of stability.
Treatment with radiation or surgery is generally considered if and when the tumor shows clear growth.
Who it tends to suit: Observation is often chosen for smaller tumors, for older patients and for people with few or mild symptoms. For people who still hear well, waiting may offer the best chance of keeping useful hearing for as long as possible.
Important to know: Hearing can gradually decline over time even if the tumor is not growing. This is a normal part of the condition and does not mean that observation was the wrong choice. More about this is on the hearing loss page.
Radiation (Stereotactic Radiosurgery)
Despite the word "surgery" in its name, stereotactic radiosurgery is not an operation and involves no incision. It delivers a precisely focused dose of radiation to the tumor, often in a single session and sometimes divided over several sessions, using technology such as Gamma Knife or a specialized linear accelerator (LINAC or CyberKnife).
Key points:
The goal is to stop the tumor from growing, not to make it disappear. The tumor usually stays the same size or shrinks slowly over time.
It is generally offered for tumors up to roughly 2.5 to 3 centimeters.
Tumor growth is controlled in roughly 90% or more of patients over the long term.
It is minimally invasive, typically done as an outpatient, with a quick return to normal activity.
Possible risks and trade-offs:
Hearing loss is the most common concern. Even with modern techniques, a meaningful number of people lose useful hearing in that ear over the years after treatment. Keeping the radiation dose to the inner ear (cochlea) low helps protect hearing.
Facial weakness is uncommon with modern low-dose treatment (around 1% or less).
Numbness or discomfort in the face, from an adjacent nerve, occurs in a small percentage of people.
Very rarely, radiation can cause other problems such as fluid buildup in the brain (hydrocephalus) or, extremely rarely, a new tumor years later.
If radiation does not control the tumor, surgery may be needed afterward, and it can be more complex than surgery would have been without prior radiation.
Regular MRI monitoring continues for years after treatment.
Surgery (Microsurgical Removal)
Surgery removes the tumor through an operation performed under a microscope. It is generally the preferred treatment for larger tumors (over about 2.5 to 3 centimeters), for tumors pressing on the brainstem and for tumors causing significant symptoms.
There are three main surgical routes, each with different trade-offs for hearing and for reaching the tumor:
Translabyrinthine goes through the inner ear structures. It sacrifices hearing on that side but gives excellent access, and is often used for larger tumors or when hearing is already poor.
Retrosigmoid goes behind the ear and can be used to try to preserve hearing.
Middle fossa goes above the ear and is used mainly for smaller tumors when hearing preservation is a priority.
Key points:
Surgery physically removes the tumor and provides tissue to confirm the diagnosis.
It is the most definitive option for large or symptomatic tumors.
Whether hearing can be saved depends heavily on tumor size and hearing before surgery; preservation is more achievable with smaller tumors.
Possible risks and trade-offs:
Hearing loss on the treated side, sometimes complete and permanent.
Facial nerve weakness, which may be temporary or, less often, lasting.
Balance disturbance and dizziness, which usually improve with time and rehabilitation as the brain adjusts.
Standard surgical risks such as spinal fluid leak, infection or, rarely, more serious complications. The risk of death is very low.
Outcomes are generally better at centers that perform a high volume of these operations.
Rehabilitation and Support
Whichever approach is chosen, there are ways to manage lingering symptoms:
Balance (vestibular) rehabilitation is a form of physical therapy that helps the brain compensate for dizziness and imbalance, and is especially helpful after surgery. See treatments for dizziness and balance disorders.
Hearing options, if hearing is lost on one side, may include special hearing aids or, in selected cases, implantable devices such as a bone conduction implant. See treatments for hearing loss.
Support for facial weakness may include eye protection, therapy and other treatments if needed. See treatments for facial weakness and paralysis.
How the Decision Is Made
There is no one-size-fits-all answer. The factors that most shape the choice include:
The tumor's size, location and whether it is growing.
Current hearing in both the affected and the other ear.
Age and overall health.
Symptoms and how much they affect daily life.
The person's own values and comfort with each option's trade-offs.
Research has found that, over the long term, quality of life tends to be broadly similar across observation, radiation and surgery. This means personal priorities, such as avoiding an operation, protecting hearing as long as possible or having the tumor definitively removed, are a legitimate and important part of the decision.
Questions Often Discussed With a Care Team
How big is the tumor, and is there any sign it is growing?
Given current hearing, which options offer the best chance of keeping it?
What are the specific risks of each option in this situation?
How many of these tumors does the center treat each year?
If watchful waiting is chosen, what findings would lead to treatment later?
Would a second opinion be helpful?
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