I also had a regrowth. In 1990 I had surgery and was told "we think we got it all", I did not have a follow up MRI until 1997, and at that time thwy told me what they were seeing was scar tissue, in 1999 the mri showed growth (hence not scar tissue), I remained in "watch and wait" for a few years then had the regrowth removed (surgery) by my choice,,,,,second time around much easier than the first.
I did not yet have to have the regrowth removed but chose to do so at that time, before it had the chance to get too big. I was offered gamma knife but declined (I had nothing left to save having lost hearing,balance and facial nerve the first time around).
I myself found being "watch and wait" very stressful as the orginal tumor was very large ,and the doctor's said they didn't understand how it was that it was so big for someone so young (based on what they know about usual growth rates of AN's it shouldn't have been so big even if I wa born with it), hence I was worried it would all of a sudden take a great growth spurt for some reason.
I do not regret having the regrowth taken care of when I did nor how I did, it was a great relief it know it was gone.
"WHAT" to do at this point is a personal choice, one only you can make.
Kathleen