I would have a discussion with your doctor about this asap. I'm assuming you're cleared for travel and to a hot, sunny place to begin with.
I would imagine that Celebration Hospital would be able to help. If not South Lake Hospital in Clermont has a cancer center and I'm sure they could. Both of those are smaller, community hospitals and the one time I was in South Lake I couldn't believe how organized and peaceful it was, as opposed to other hospitals I've been in in the past.
But I think the first step would be speaking to your doctor. It's quite possible that his office will be able to set something up for you.
Have a great trip!
Anne