Radiosurgery, Resection, Fractionated or Observation?

A survey was mailed to members of the Congress of Neurological Surgeons in July 2002. Six hundred sixty-three surgeons responded to the survey (30%). The survey was mailed with four questions written on one page. Forty one percent of responders were between the ages of 40 and 50. Eighty percent of neurosurgeons surveyed had either performed radiosurgery on a patient with an acoustic neuroma or had referred a patient for neurosurgery (n=530).

Survey Case One: You are a 37 year-old neurosurgeon who presents with mild decreased hearing on one side. You have no tinnitus and no balance problems. Facial function is normal. An MRI scan (right) shows an intracanalicular acoustic neuroma and serial scans have shown a small amount of growth. Which management strategy would you choose for yourself -- observation; surgical resection; stereotactic radiosurgery; fractionated radiotherapy?

Response: The majority of surgeons stated that they would choose stereotactic radiosurgery for management of their small acoustic tumor (n=283; 43%). Only 122 surgeons stated that they would choose surgical resection of their tumor (18%). Fractionated radiotherapy was chosen by 2% of responders. Interestingly, 240 surgeons stated that they would continue to observe their tumor (36%) rather than undergoing any specific treatment at the present time. It had been stated in the case presentation that serial scans had already shown a small amount of growth. This tumor had been observed and was increasing in volume. Nevertheless, approximately one-third of responders continued to choose observation for a 37 year-old patient with a small, but growing tumor.

Table 1 (Survey Case One Responses):

We evaluated the age of the responding surgeon and compared this to the treatment chosen by that surgeon . Across the age groups between 30 and 70 years, at least twice as many neurosurgeons chose radiosurgery for their tumor rather than resection. This is most pronounced in the younger surgeon age group (30 - 40 years), where four times the number of surgeons chose radiosurgery rather than resection. However, observation continued to be chosen by many. While one might think than an older person might choose radiosurgery over resection, simply to avoid the risks of general anesthesia or the surgical exposure, this did not necessarily appear to be true. This case reflected the care of an actual neurosurgeon who had gamma knife radiosurgery. He remains well 18 months following his procedure, and maintains a full practice. He has had no facial weakness or change in hearing.

Survey Case Two: You are a 50 year-old neurosurgeon who presents with mild decreased hearing on one side. You have tinnitus but no balance problems. Facial function is normal. An MRI (right) shows a left acoustic neuroma. Which management strategy would you choose for yourself -- observation; surgical resection; stereotactic radiosurgery; fractionated radiotherapy?

Response: In this scenario, the neurosurgeon had a medium size acoustic tumor that indented the middle cerebellar peduncle but without compression of the fourth ventricle. The tumor measured 22 mm in the maximum diameter. The minority of surgeons recommended continued observation for a tumor of this size (6%) (table 2). Surgical resection was recommended by 347 surgeons (52%), whereas radiosurgery was chosen by 261 surgeons (39%). Fractionated radiotherapy was only chosen by 3%. When the results were stratified by age, resection was the most popular choice across the groups between the ages of 30 and 60. However radiosurgery became more popular with advancing age of the survey group, passing resection as the most popular choice when the neurosurgeon is over age 60. It appears that surgeons chose to have a resection because of the larger volume of the tumor with indentation of the lateral surface of the brain stem. This patient was also a real neurosurgeon who had radiosurgery. He remains well 18 months after the procedure with a decrease in the size of the tumor. Facial function remains normal.

Table 2 (Survey Case Two Responses):

Patients with acoustic neuromas have several options available to them. Large tumors with significant brainstem compression usually require surgical resection. For patients with small or medium sized tumors, radiosurgery has become a common treatment with excellent long-term results reported. It is interesting to see how neurosurgeons themselves choose treatments as if they were the patient.

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