Columbus-guy, I'm doing pretty well, thanks for asking. Actually my tumor was at stage IV when I was diagnosed...it moves quickly and tends to be aggresive. I was lucky to have some of the best medical expertise in Canada, right in my back yard. Treatment was as good as it gets, and everything is looking good.
There is nothing that you can take specifically that will ward off cancer. Good eating habits, brushing your teeth regularly and maintaining good oral hygene, and generally living a healthy lifestyle are the things to do.
As Leslie said, the best defence is vigilance. If you see something unusual, get it checked.
You're on a forum right now with a TON of people who practice that vigilence through close, regular self-examination of their mouths. It only adds a few seconds to your tooth-brushing ritual, and it could save your life
Wayne