uri in dogs

my 11 year old **** zhu has been having uri infections with a little blood in the urine, the vet put her on clavamox but once she had taken the course it reocurred, he did an ultra sound,  no kidney stones her kidneys looked good but said there was a thickening of the bladder wall, with no other test he is talking about a biopsy, which I have been not is not the best thing, have heard there is a urine test that can detect bladder cancer, she is on a second course of clavamox, again 100 per cent better, no other symtoms (symptoms), eating, drink playing as normal, would value some advice

[Dan Sims, DVM]

Bladder cancer usually results in large amounts of blood in the urine and if there is a generalized thickening of the bladder then chronic UTI is more likely.
A urine culture ( off antibiotics for 72 hours) and 8 weeks of  the appropriate antibiotics may be the answer.Bladder cancer is usually pretty obvious in the the hands of an experienced Veterinarian .
There is no blood test for bladder cancer but there is a very safe medicine that can help treat this disease called peroxicam.By the time this cancer causes clinical signs it is too late for surgical intervention.