Brain mets from colon cancer

I was diagnosed in May with stage 4 colon cancer with mets in the liver, lung and brain. Chemo has shrunk the tumors in the liver and lung and I had Gamma Knife on 9 spots in the brain which seemed to shrink all of them as well. Now they have found that 2 of them are growing slightly again. Problem is, the larger one sits in the area which controls the left side of my face. Dr says 5 to 10% chance of damage which will result in similar to Bell's Palsey (sp). Other option is whole brain but I'm told always results in side effects which become worse as time goes by. Does anyone have experience with on or both? Especially multiple Gamma Knife or Cyber Knife to the same area of the brain? Any help with this decision will be greatly appreciated.
Thank you in advance
Dave