I just found out at the vet yesterday that my cat, Monkey, most likely has cancer

. I just lost a cat a couple of years ago to cancer, too. They are going to do surgery to remove the tumor. Has anyone else had to deal with cancer in a pet? I'm mostly concerned with, if the vet recommends any kind of chemo or radiation after the surgery, what would that do to his quality of life? What would you guys do in that situation?