This could be out of date or just plain wrong - for all I know it's one of those "folk wisdoms" that are just misheard or made up - but there are supposedly cancers that go nuts when exposed or cut. I dunno - this almost seems like a question for that Nancy person, because she could get Mr. Meow's opinion and maybe even more information. (Her name is Nancy, right? The cat psychic?)

My only personal reservation is that depo weakens the immune system, and so Mr. Meow would be unusually susceptible to infectious complications, but I'm sure your vet knows how to deal with that.

Whatever happens, you've taken a sad little cat and made him happy, shown him the kind of love that every creature deserves, and been a friend to somebody who really needed one. Sometimes that can be, if not enough, a real comfort, if you take it as seriously as Mr. Meow has in his gentle kitty soul.

Love, Columbine