Re: cancer treatments
I have not, nor do I think I would. Unless the treatment outcome has a very high percentage of sucess, like great results for certain procedures or catching it in the early stages before it progresses to become system-wide, I would not put a cat through any procedure unless I knew (or felt confident) that the pet could be cured and live a good life afterwards.
I have to have chemo pills/shots (I don't have cancer, I have an auto-immune disorder) and they make me feel nauseated and icky. I can't imagine how a small kitty would feel, especially where food ingestion is critical for maintaining weight and energy.