Rockyb,
In my opinion both GK and CK can effectively treat AN. And there are many people on this forum who have been treated successfully by one or the other. I would lean toward a treatment team that has lot's of experience treating AN with the machine they plan to use. The treatment is only as good as the treatment plan (what amount of radiation goes where) created from their experience and expertise, and their knowledge of your AN. CK is CK, and GK is GK, but the treatment would be slightly different from each treatment team. Find the team with the most expericence treating AN you can locate.
Good luck with your AN. If you're like most of us, investigating the various treatment options, weighing the odds and statistics amoung uncertainties, and making a decision for treatment, can be the toughest part.
Regards,
Rob