I think the most realistic thing to tell your aunt is that, while there are no guarantees in life, the rate of serious side effects from radiosurgery is very low. I had a small AN zapped in January, and I 've had no side effects. I'm going to paste in an excerpt from a University of Pittsburgh survey of their radiosurgery patients:
FROM THE WEBSITE:
www.acousticneuroma.neurosurgery.pitt.eduWhen asked whether Gamma Knife radiosurgery met their initial expectations, 106 patients (92%) said yes. This included 97% of responders in the prior surgical resection group and 91% in the no resection group.
Complications were described by 36 patients (31%) and most of these were minor, 56% of which resolved. The majority of the symptoms were not those usually considered to be complications after a resection, but just typical of some of the complaints that an acoustic neuroma patient may have.
Radiosurgery was described as a "successful" treatment by 30 of 30 patients who had undergone prior surgery and by 81 (95%) of those who had not undergone a prior resection. When asked if they would recommend the procedure to a friend or family member, 109 (95%) said yes, two said no, and four said they could not answer for another person.