From all I have read, interviews and presentations I have seen. Webinars attended. I think it will be worth contacting Dr Rick Friedman
http://www.keckmedicine.org/rick-a-friedman-md-phd/Gamma knife is an option too. One study has placed the risk of malignant transformation at 14 per 100,000 people at 20 years if my memory serves me correctly. Risk at 80 years will probably end up being between 50-100 per 100,000. A small risk but not insignificant.
I have a 15 year old daughter and wondered what I would do?
I had Cyberknife which is similar to Gamma Knife, and I am very happy with my decision.
If it were my daughter I would be seriously exploring the very best surgeon out there, as I believe this would give the best chance of living a completely normal life.
I am a huge fan of radiation, Gamma Knife I believe would be a better choice than Cyberknife due to better radiation shielding, reducing cancer risk to the rest of the body.
Radiation on small tumours has great hearing preservation rates short term. But the hearing preservation rates at 10-20 years are not fantastic.
It's a tough decision, but due to your sons young age, it's extremely unlikely that Watching and Waiting is an option.
Another thing to consider is that people that get AN's younger tend to have tumours that are more aggressive. Faster growing tumours tend to be more resilient to treatment too.
Keeping radiation in the kit bag after surgery could be another consideration.
Good luck with everything...