My dog has TCC please help

Hi
I have a 10 1/2 year old staffordshire terrier who has been through a lot. 8 months ago she has blood in urine and we thought it was a UTI. Long story short they found a very small mass on her bladder. A rare case I was told, her tumor was located on her dorsal bladder wall thus it was able to be surgically removed. I went ahead and did this but at the time of the surgery her kidneys started to fail. They closely monitored her and were worried so took a biopsy of her kidney. She ended up having renal amyloidosis which is basically kidney disease and is rare in her breed. They told me that she had 2 fatal diseases. Her recovery was a week of hell and I thought I was going to have to put her down then.
8 months later which is now, she has been doing great. You would never know she has been sick. So she gets check ups very often and she got a UTI recently. Today she had her ultrasound and they tumor has come back in same place. I don't know what to do. The problem is her kidneys are stable and doing well but they still aren't very good. They did say that surgery was an option again but would have to remove 75% of her bladder which would be hard for her to hold urine for a while. But it is scary because of her kidneys to put her under again. The other option would be to start her on a low dose of Piroxicam and she how her kidneys respond to that. I am at a loss. The vet said that the cancer will keep coming back. I wish they could tell me, if I do the surgery again she will live another year or more. But they can't. And recovery would be harder this time around I think. She is so happy right now and doing well. I just don't want to see her get sick. Does anyone have experience with this?