I'm the OP for this thread and am updating it with the results of my 1-year post-CyberKnife MRI:
I met with the radiation oncologist today, 04/19/2018, to get the results of the 1-year MRI that was done 2 days ago. The tumor is smaller than at the 6-month post-CK MRI. It is now 18mm x 11mm x 11mm compared to 20.6mm x 12.9mm at 6 months. (The full history of the measurements is in my signature). This was the first time the third dimension was specified by the radiologist who interpreted the MRI; always before they only stated 2 directions.) The radiation oncologist felt this represented actual shrinkage of the tumor and not just measurement error.
I have had no post-CK problems other than mild hemi-facial spasms for a couple weeks at about 4 months post-CK. I have no useful hearing left in the AN ear (right ear), but that was the case even before CK. Mild tinnitus in the AN ear, but no worse than before CK. No noticeable balance problems.
The doctor scheduled another MRI for one year from now. I'll update this thread then, unless something happens in the meantime, such as new symptoms.