Is the cat underweight because she isn't eating? Perhaps spoon or even bottle feeding her may be in order. Also, make sure she gets plenty of water.

It may not be helpful or compassionate to put the cat through too many medical procedures if it is so sick.

The main thing you can do is support your friend right now.

Good luck. I wish I had more to suggest.

Very important to keep her hydrated as well....try diluting a bit of Gatorade with water and giving it to her with a medicine dropper....this will help to balance her electrolytes. You may want to get kitten formula which you can always feed to her with a dropper. Good luck.

My 14 year old male cat is skin and bones he eats like crazy but not gaining..I think he has feline leukemia..He doesn't act like he is in pain..He drinks alot and still gets around really good..He had had a cancer on his foot years ago and the vet said it would probably come back and be spread to other areas that there wouldn't be anything they could do..It is heart breaking but all you can do is keep them comfortable..

Try everything you can, is she not eating? You could try hard food softened with water. If the cat is in pain and noody can help her... to stop the pain you should put her to sleep. I know it will be hard, but that cat had 15 great years. Do whats best for her and her cat.