What causes TCC in dogs?

The exact cause of TCC in an individual dog is usually not known. In general, canine TCC results from a combination of several factors including genetic predisposition and environmental factors. A genetic predisposition is suspected because TCC is more common in specific breeds of dogs, including Scottish Terriers (18 fold increased risk compared to other breeds), Shetland Sheepdogs (4 fold increased risk), Beagles (4 fold increased risk), West Highland White Terriers (3 fold increased risk), and Wire Hair Fox Terriers (3 fold increased risk). Environmental factors identified as risk factors in previous studies have included pesticides and insecticides including "old generation" flea dips. The greatest cause of TCC in humans is smoking, but further study is needed to determine the extent to which second hand smoke may contribute to TCC in dogs.

Source: http://www.vet.purdue.edu/vcs/Pcop/caninebladder
cancer.htm

What clinical signs, or symptoms do dogs with TCC have?

Blood in the urine and straining to urinate are the most frequent signs of TCC. Pet owners must realize, however, that a urinary tract infection will cause these same symptoms, so the symptoms alone do not necessarily mean their dog has TCC. Less commonly, dogs with TCC can have lameness due to spread of the tumor into the bones or spread into the lungs and a paraneoplastic syndrome hypertrophic osteopathy.

Source: http://www.vet.purdue.edu/vcs/Pcop/caninebladder
cancer.htm

Personal note:  I knew something was wrong with Copper when I noticed he was straining to urinate.  I took him to the emergency vet and I suspected that it was a urinary tract infection.  I didn't know dogs could get those but after doing research on the Internet I found out they could.  The ER vet agreed with me and instead of doing an expensive work up we decided to treat him with antibiotics.  1 week later I noticed that he was still straining to urinate and he had begun to leak urine.  At first it was a little dribble and then at night his bed would be soaked.  I then took him to his regular vet and after urine tests, x-rays, blood tests and finally an ultrasound and a tissue biopsy he was diagnosed. He has a tumor in his bladder and it is cancer however, it had not spread to any other organs. The tumor is located by the neck of his bladder which makes operating on it almost impossible. The total bill just to get a diagnosis was around $700.00.

How is TCC diagnosed?

To diagnose TCC requires a tissue biopsy. Several other types of growths in the bladder, bladder infection, bladder stones, or bladder inflammation can cause similar symptoms as those in dogs with TCC. Some of these other conditions can also cause "masses" to be seen on radiographs or ultrasound. Some of these other conditions can cause abnormal cells in the urine, which can be mistaken for TCC. Therefore, diagnosis of TCC requires a tissue biopsy. This is important because the treatment and prognosis depend entirely on exactly what is wrong with the bladder. A tissue biopsy can be obtained by surgery, cystoscopy (insertion of a fiberoptic scope into the bladder and biopsy through the scope), or in some cases with a urinary catheter.

Source: http://www.vet.purdue.edu/vcs/Pcop/caninebladder
cancer.htm

How is TCC treated?

For dogs with TCC that has not spread beyond the bladder, surgical excision could be considered. In order to surgically excise the tumor, however, it needs to be located away from the neck of the bladder and the urethra. Several vital structures in the neck of the bladder (junction with ureters and urethra, urethral sphincter) make surgical excision in this location usually impossible. This is especially true because malignant tumors, like TCC, need to be removed with a "margin" of normal tissue around the tumor. This "margin" often contains microscopic tumor cells that, left behind, would result in cancer regrowth. In addition, most canine TCCs invade down into the bladder wall and therefore, surgical excision requires removal of a complete full thickness section of bladder wall. Note: in humans with superficial, low grade cancer, this is not typically the case. Because most canine TCCs are invasive into the bladder wall and located in the neck of the bladder, surgical removal is not possible. It has not yet been determined if removing part of the tumor (in dogs in which the entire tumor cannot be removed) is beneficial or not.

If surgery is not possible, what other treatment options are available? Radiation therapy has been used to successfully control TCC growth in the bladder in dogs. Unfortunately, radiation of the bladder can lead to harmful complications including a scarred, shrunken bladder, and irritation to surrounding organs. To use radiation therapy successfully in TCC, different treatment schemes need to be developed.

The vast majority of TCC cases are treated with medical therapy, i.e. with drugs. Two broad categories of drugs have been used to treat TCC. Traditional chemotherapy using cisplatin, carboplatin, adriamycin, and others have been used in canine TCC. The response has been rather disappointing with <20% of dogs having remission. The other type of drug that has been used against TCC is a nonsteroidal antiinflammatory drug (NSAID), piroxicam. NSAIDs include piroxicam, aspirin, ibuprofen, naproxen, and others. We became interested in piroxicam when we began using it for pain relief in dogs with cancer, and observed unexpected remissions. Two of the first dogs treated (one with metastatic carcinoma, one with undifferentiated sarcoma) had advanced cancer and had remission of their cancer when only receiving piroxicam. This has led to numerous studies of piroxicam in animals with cancer at Purdue. In 55 dogs with TCC treated with piroxicam, the tumor decreased in size by > 50% in 9 dogs, remained "stable" in size (<50% change) in 32 dogs, and increased in size by > 50% in 14 dogs. The median survival (190 days) compared favorably to survival with chemotherapy in other studies.

In an attempt to improve the response of TCC to therapy, we conducted a study comparing chemotherapy (cisplatin) alone to chemotherapy plus piroxicam. In this study the combination of cisplatin and piroxicam was more effective against the cancer, but the combination treatment caused a rise in the urea level in a blood test. Although dogs did not have outward symptoms of kidney problems, this rise in urea level in the blood tests indicated that the combined therapy was being toxic to the kidneys. In fact in several instances, the cisplatin therapy was withdrawn (so as to not cause kidney damage) while the tumors were still shrinking. We are currently evaluating other chemotherapeutic agents combined with piroxicam to determine if enhanced tumor killing will occur in the absence of increased toxicity.

The side effects of chemotherapy are usually tolerable in dogs. Information of specific medications can be discussed with the attending veterinarian. Piroxicam has few side effects. In some dogs, however, piroxicam will irritate the stomach or intestine. Therefore, if a dog on piroxicam has loss of appetite, vomiting, or dark tarry-looking stools, it is safest to stop the piroxicam and consult the veterinarian before starting the medication again.

In addition to these therapy approaches, we are constantly looking for new "targets" to treat bladder cancer. Chemotherapeutic agents damage the DNA in cancer cells, but unfortunately damage the DNA in normal cells at the same time. We are looking for "targets" that are present in the TCC, but not in normal cells. We are collaborating with other scientists to identify these new targets, and will develop clinical studies for them in the future.

Personal note:  Copper was prescribed Piroxicam and did not have any side effects.  The prescription had to be refilled every 30 days and its costs $30.00.