Kendra,
I feel worried for you, too.
Are you feeling well enough to suggest to your doctor to wait before starting Cellcept...to be sure all of the effects of the Acrylin (sorry I don't know how to spell it) have worn off first. Maybe you won't need the Cellcept if give your body time to adjust to no more Acrylin.
Sometimes I feel like doctors are too quick to start us on new medicines, even before a previous medicine has time to take effect.
I know that I can currently manage my MG with Mestinon and I am glad for that. If I were still in bad shape, then I would consider another drug, even if it had a risk of cancer. I haven't taken Cellcept or anything besides Mestinon for my MG. This is a difficult decision to make. Definitely worth the time to think about it and consider all your options before making a decision. I wish I could be of more help. You are the one that can make the best decision for you.