My AN was only 2.2 X 1.6 and was pressing pretty good on the brain stem. It was recommended by many doctors that radiation would be a good choice. Non mentioned a problem being on the brain stem.
Here is how I see it. Under 2.5, there is very good success rates with radiation. Over 3cm and the success rates go down some. As to that percentage is debatable between doctors. There are other considerations also when over 3cm. It pushes on a lot, and getting it out to create some room and relieve pressure is needed with some. So the grey area is 2.5 - 3cm. I think this is important information especially for people in the watch and wait status. The larger it gets, the less options you have. I am not seeing a trend away from radiation in that grey area, actually I see more and more docs pushing that grey area with radiation.