My friend has a guinea pig, Rose, that has a large cyst on her left haunch. It is about half as big as a kiwi. The vet drained it, gave liquid to flush it and some antibiotic. and wants to remove it, but says it is probably cancerous. I read that cavies have cysts and they do not mention cancer. It seems to be the norm. She is about 3-4 years old. What do you think?