The GreenStar and Omega juicers should be good for those with or without cancer. I am fighting cancer myself, and I chose the GreenStar. I have a friend with cancer who uses the Champion and is having good results. I have only read the info on the omega juice, but it seems fine as well. What matters is the quality of juice, and I would like to see lab data that showed the the Normalk had any superior qualities to the GreenStar or Omega.
If Sharon's mom were to choose to go 100% Gerson, then perhaps she should worry about the juicer. IMO, I do not believe that the choice of juicer will have any impact on the outcome as long as the juicer is a quality low-speed masticating or press type juicer.