An acoustic neuroma, also known as a vestibular schwannoma, is a non-cancerous growth that develops on the main nerve running from the inner ear to the brain. Since the condition is not a malignant cancer, the question of whether it can be cured is complex. This slow-growing tumor affects the nerve responsible for transmitting sound and balance information. Management involves a spectrum of approaches, ranging from active monitoring to aggressive intervention. The ultimate definition of a successful outcome depends heavily on the chosen treatment path and the patient’s long-term quality of life.
Understanding Acoustic Neuroma
An acoustic neuroma is a benign tumor that originates from the Schwann cells, which form the insulating myelin sheath surrounding nerve fibers. The tumor forms on the vestibulocochlear nerve (the eighth cranial nerve), which leads from the inner ear to the brain. Although these tumors do not spread to distant parts of the body, their growth within the confined space of the skull causes problems.
The slow expansion of the tumor puts pressure on surrounding nerves and structures, resulting in characteristic symptoms. The most common initial symptoms are a gradual loss of hearing, typically in one ear, and persistent ringing or buzzing (tinnitus). As the tumor enlarges, it can also affect the adjacent facial nerve, leading to facial numbness or weakness, and may cause balance issues. Diagnosis is typically confirmed using a gadolinium-enhanced Magnetic Resonance Imaging (MRI) scan, which can detect tumors as small as one to two millimeters.
Watchful Waiting and Observation
For many patients with small tumors and minimal symptoms, the initial strategy is watchful waiting or observation. This is an active, conservative management plan, not simply ignoring the diagnosis. The tumor is carefully monitored over time through annual or semi-annual follow-up MRI scans and hearing tests.
This strategy is often recommended for older adults or those who are poor candidates for surgery. It is also appropriate for small tumors (less than two centimeters) that are not growing rapidly or causing significant neurological deficits. The goal of observation is to avoid the risks of active treatment for a tumor that may never grow to a problematic size. Some acoustic neuromas stop growing entirely, and in rare cases, a tumor may even shrink slightly.
Watchful waiting carries the risk that the tumor may grow larger, potentially leading to greater hearing loss or other symptoms. If serial imaging shows continued growth, or if symptoms worsen significantly, the care team will transition to a more definitive treatment approach. This decision balances the risks of a growing tumor against the risks of intervention.
Definitive Treatment Approaches (Surgery and Radiation)
When active intervention is required, the two primary definitive treatment options are microsurgery and stereotactic radiosurgery. The choice depends on the tumor size, the patient’s age and health, and the primary goal of the intervention.
Microsurgery
Microsurgery involves physically removing the tumor, and it is the only treatment that can achieve the traditional definition of a “cure” by entirely eradicating the growth. The surgeon removes as much of the tumor as possible while attempting to preserve the function of nearby nerves, such as the facial and hearing nerves. Complete surgical removal significantly reduces the risk of recurrence, which is typically less than five percent. Surgery carries risks, including a higher chance of immediate facial nerve weakness or paralysis and long-term hearing loss, particularly with larger tumors.
Stereotactic Radiosurgery
Stereotactic radiosurgery, using technologies like Gamma Knife or CyberKnife, provides a highly focused dose of radiation directly to the tumor. The goal of this treatment is biological control, aiming to stop the tumor cells from dividing and growing, rather than physical removal. The success rate for stopping tumor growth is high, often greater than 90%, with the tumor remaining stable or shrinking over time. Radiosurgery is associated with a lower risk of immediate facial nerve damage compared to surgery, but it does not remove the tumor mass.
Defining Resolution and Long-Term Outcomes
For an acoustic neuroma, the concept of “cure” is nuanced and often redefined as long-term tumor control with an excellent quality of life. Only successful total surgical removal offers physical eradication, but long-term monitoring after radiation or observation is also considered a successful outcome. For those treated with radiosurgery, tumor control—meaning the tumor does not grow further—is the benchmark of success, which is achieved in the majority of cases.
Even after successful treatment, patients may still experience residual symptoms. Existing hearing loss or balance issues caused by the tumor’s initial pressure often do not resolve fully. Long-term follow-up is necessary for all patients due to a small but persistent risk of recurrence after subtotal removal or continued growth after radiosurgery. Ultimately, a “cure” is best viewed as achieving a state where the tumor no longer poses a threat to neurological function or quality of life, which is a highly achievable outcome for most individuals.