What do you think you would do if the very worst happened, and it was cancer?
I think you would deal with it, because that is what we all do when disaster or illness strikes.
We go through it, and we (hopefully!) come out the other side.
Apart from that, is there any illness which is prevented or helped by worrying?
That's my take on health issues. Give yourself enough credit to know you would be strong and resilient, because humans are just that.