CyberKnife for Acoustic Neuroma
Almost any patient can be treated with Cyberknife radiosurgery for acoustic neuroma. Some patients who are particularly symptomatic, either from pressure symptoms, tinnitus, or imbalance, may be best treated with surgery, because surgery will relieve the symptoms more rapidly. In addition, certain large tumors (greater than 3.0 cm in size), are best treated with surgery because these tumors can sometimes swell and cause obstruction of the flow of cerebrospinal fluid. All other lesions are generally excellent candidates for Cyberknife radiosurgery
Treatment Process
Treatment consists of imaging with a CT scan. The CT scan is then imported into the Cyberknife Treatment Planning System. The neurosurgeon or otolaryngologist then team up with the radiation oncologist and radiation physicist to create a plan which will appropriately treat the tumor while avoiding surrounding important sensitive structures. This process is done over several days’ time so that appropriate input can be garnered from all involved, and so that an extensive quality assurance program can be completed prior to treatment.
When it is time for the patient to be treated, they are brought into the treatment room. A mask which was made at the time of the initial CT was placed, which increases accuracy, while keeping the patient in a stable, but comfortable position. Treatment is generally completed within 1-1 ½ hours. The treatment is painless and generally does not require sedation or analgesia.
Treatment Effectiveness
There has been so much experience with Radiosurgery from acoustic neuroma, the chance of experiencing side effects is very low. The chance of experiencing temporary numbness or weakness of one side of the face is 2-3%. Preservation of useful hearing is generally achieved in 50-75% of the time. There are no risks of bleeding or infection, and almost no recovery period.
Radiosurgery is effective approximately 90% of the time in treatment of acoustic neuromas. Most tumors will stabilize in size, and then will shrink slowly. Shrinkage occurs in approximately 1/3 of tumors within a year after treatment. After 4 years, 2/3 of tumors are smaller, and within 10 years, more than 90% have diminished in size.
In the rare cases that radiosurgery does not result in control of the tumor (which is defined as either stabilization or shrinkage of the mass), it can generally be repeated, or the patient may undergo surgery at that time.
Summary
Cyberknife Radiosurgery is an excellent treatment approach for patients with acoustic neuroma. The tumor is controlled approximately 95% of the time, and the risk of serious side effects is extremely low.
Links & Resources
- CyberKnife Society: http://www.cksociety.org
- Acoustic Neuroma Association: http://www.anausa.org
- MedLine Plus: http://www.nlm.nih.gov/medlineplus
- American Hearing Research Foundation: http://www.american-hearing.org
- National Institute of Deafness: http://www.nidcd.nih.gov
- Acoustic Neuroma Patient Archive: http://www.anarchive.org
