Bladder cancer in dogs is usually malignant, and the most common type is transitional cell carcinoma (TCC). TCC is a cancer that originates in the bladder, kidney or ureters, but the most common site for this type of cancer is the bladder. It arises in the transitional epithelium, the membranous tissue covering these organs.
The exact cause of TCC is not totally known, but it is suspected that carcinogens that pass out through the urine lead to development of cancer in the lining of these organs. Since the carcinogens tend to be stored in the bladder along with urine, the bladder is the most affected organ. Some drugs are also known to be metabolized by the liver to produce acrolein, a known human carcinogen. As acrolein is produced in the liver and passed out through the urine, it is also suspected to be one of the causes of urethra and liver cancer in dogs.
Symptoms of bladder cancer in dogs tend to remain hidden long before diagnosis is done, as most of the symptoms resemble those of a common urinary infection. If your dog is showing the following symptoms, which refuse to go away even after treatment, further investigative tests should be done to rule out cancer.
- Bloody urine.
- Difficulty or straining while urinating and defecating.
- Small amounts of urine leading to increased frequency.
- Troubled or heavy breathing and coughing.
- Intolerance to exercise.
Some of the specific tests that can be performed to confirm or eliminate the prevalence of bladder cancer include rectal examination, cytological examination of urine and contrast dye X-Rays. Urethrocystoscopy, which is the use of a use of a cystourethroscope (an endoscope) to evaluate lesions or foreign bodies in the bladder, urethral herniation, fistulas, strictures, and other conditions, may also be used if these tests do not confirm a diagnosis. The procedure is also used to get a sample of the tumor tissue for biopsy.
Bladder cancer in dogs is a fatal disease and prognosis is poor. This is mainly because in most cases, the cancer has already spread to other parts of the body by the time it is diagnosed, leaving very few options for cancer treatment in dogs. Survival time, if the condition is not treated, ranges from a few weeks to less than a year. Surgery is not an option because TCC cells are found in many parts of the bladder, which are difficult to approach. Chemotherapeutic drugs have shown some promise, but much depends upon the location of the tumor and the extent of metastasis.