Tower,
My kids are grown and my grandson is only 4 - he thinks the doctors cut my head off and sewed it back on again, and he is very careful of my neck scar, but of course he is too young to be scared of the c-word.
I think you have the right idea - your kids deserve honest answers, and they know things are not right. I would be prepared with a list of cancer survivors they know or know about, when you tell them, so you can remind them that lots of people have lived through what you are going through. And if you can tell them what they can do to help, they'll feel better. You will be sick after the radiation, and they'll have to deal with that too (and it is no fun for the family, ask my husband!)
How can we explain somethign we don't want to face ourselves? I know I told everybody I had had a cancer operation, but it wasn't anything to worry about, and then I was upset when they believed me and did not worry! But your children are going to worry, so you will have to try to put as positive spin on this as you feel you can.

Good luck - keep your teeth clean and complain to the doctors and nurses about every little pain and discomfort you have - there are remedies for most of them. And when they don't help, ask us - somebody here has had every problem that you can have.

love, Leena