Patty,
How long ago did you receive Cyberknife? The technology is the same as Gamma Knife which Christine had.
Her tumor grew a little just before it died. Her rad/onc said that this often happens. With Christine, I believe it was around 12-a5 months after her GK.
Here is a link to a Cyberknife Support Group perhaps they can help you also:
Cyberknife Support
Warmest Regards
Joe