Penny had mouth cancer. The vet said we could try antibiotic for 48 hours but really we were talking weeks and she was fairly certain it was mouth cancer. There was no real decision. I held Penny in my arms as she was given the sedative. Afterwards, the vet was able to pull her lip back and checked -- the cancer had gone into the bone. Because she was on metacam, she did not feel the pain in the way she would have.
Personally I figure the metacam bought us an extra year with her.Penny was far more my cat. She left me alone to write but if I was watching tv, or talking to anyone or just generally sitting anywhere but my study, she was on my knee. If anyone was ill, it was her business to go and snuggle up to them. She was a very people sort of cat.
She was buried next to her sister in the warmest part of the garden. The good part is that I don't think she knew Tuppence was gone.
We will get more cats, but not just yet.