Symptoms of Bladder Cancer in Cats
Cancer of the bladder is very rare in cats. Among the different types of cancer that can affect the urinary bladder, transitional cell carcinoma (TCC) is the most commonly diagnosed. Although it’s still a rare occurrence in cats, TCC is a malignant cancer that usually arises from the lining of the bladder or urethra. In some cases, TCC can develop from the muscular wall of the urinary tract. Continue reading to learn more about the causes, symptoms, and treatment options for bladder cancer in cats.
Cancer of the urinary bladder is life-threatening. Without prompt veterinary intervention, the obstruction in the urinary tract and the cat’s inability to urinate can have serious implications and can even result in death.
TCC can metastasize (spread) to other parts of the body, particularly in major organs, such as the lungs, kidneys, and liver. Since the symptoms that are often noticed by cat parents are similar to urinary tract infections, by the time TCC is diagnosed, metastasis has already occurred in more than 50% of affected cats.
Causes of Bladder Cancer in Cats
The cause of transitional cell carcinoma has not been fully explained. Some experts believe one potential reason could be the presence of cancer-causing chemicals (carcinogens) that are excreted in the urine and to which the cells lining the bladder and urethra can be exposed.
Exposure to the older formulas of insecticides and pesticides that were used to kill fleas and ticks may also be an important predisposing factor. This may also be true with exposure to the active ingredients of spray products that are used to control mosquitoes.
Cyclophosphamide, an anti-cancer drug that is also used to treat certain types of immune diseases, is metabolized to acrolein, a carcinogenic chemical that is excreted in the urine. Experts think that exposure to cyclophosphamide may increase a cat’s risk for urinary bladder cancer.
The incidence of urinary bladder cancer is higher in female cats compared to their male counterparts. Obesity could also be an important predisposing factor for bladder cancer.
Symptoms of Bladder Cancer in Cats
- Straining to urinate
- Straining while defecating
- Increased frequency of urination with only dribbles of urine being passed
- Poor tolerance to exercise and physical activity
- Difficulty breathing
How Bladder Cancer is Diagnosed in Cats
If your cat is exhibiting the symptoms mentioned above, it is highly recommended that you make an appointment with your vet sooner rather than later.
At the clinic, your vet will get your cat’s complete medical history before performing a physical exam. This will include abdominal and rectal palpation to determine if there are abnormal changes that can be felt in the urethra, neck of the bladder, prostate gland of male cats, and adjacent lymph nodes.
Several diagnostic tests may also be performed to substantiate initial findings and arrive at a definitive diagnosis. These may include some or all of the following:
- Laboratory tests will include a complete blood count (CBC), serum biochemistry profile, urinalysis, and urine culture. These tests help evaluate the general health of the patient and to identify possible metabolic and physiologic consequences associated with urinary obstruction.
- X-rays of the abdomen and chest to evaluate for a mass and if there is an enlargement of the lymph nodes. X-rays can also help evaluate the spread of cancer to other organs.
- Bladder imaging (cystography)
- An abdominal ultrasound can assess the bladder tumor’s exact location and extent, the status of adjacent lymph nodes, and if there is any urinary tract obstruction.
- Contrast dye x-rays can be used instead of an abdominal ultrasound exam to evaluate the tumor’s extent and location.
- Tissue biopsy - This is the gold standard in diagnosing TCC in cats. This can be achieved by surgery, urinary catheter, or cystoscopy. The latter involves inserting a fiberoptic scope into the urinary bladder, and a biopsy is done through the scope. The tissues that are obtained during a tissue biopsy are then examined under the microscope.
- V-TBA - This is a relatively new test to screen for bladder tumor markers in the urine of cats that are suspected to have TCC.
The results of the tissue biopsy are very important in determining the appropriate treatment regimen and prognosis. After a tissue biopsy, an oncologist will perform the staging process. This will involve looking at three important factors associated with the cancer -- the measurement of the primary tumor, whether the cancer has spread to adjacent lymph nodes, and if metastasis (tumor spread) is present.
To check whether there is metastasis, chest x-rays, abdominal x-rays, or CT scans are performed. These procedures can also help evaluate if there are any changes in the kidneys. The tumor’s exact location and size can also be determined. During treatment, these tests are repeated to assess the efficacy of treatment.
Treatment Options for Bladder Cancer in Cats
The treatment regimen of urinary bladder cancer in cats is usually developed with the help of a veterinary oncologist. If your cat has been diagnosed with cancer of the urinary bladder, you should discuss with your veterinarian and the oncologist the various treatment options that are available for your pet. These treatment options may include the following:
- Surgery is indicated for small tumors that are confined to the body of the bladder. Many TCCs, however, develop in the neck of the bladder where vital structures are located, rendering surgical removal impossible.
- Radiation therapy can be successful but is not without complications, such as scarring of the urinary bladder and irritation to adjacent organs.
- Chemotherapy and symptomatic treatment - The most common treatment protocol for TCC in cats is a combination of a chemotherapy drug and NSAID (like piroxicam) which has been observed to result in remissions. Non-steroidal anti-inflammatory drugs (NSAIDs) can also help with pain management. Piroxicam alone can improve the survival time of patients with bladder cancer up to approximately 6 months. When combined with Mitoxantrone chemotherapy, the median survival time is generally one year.
- Cats with TCC are more prone to urinary tract infections (UTI). Your vet may prescribe a round of antibiotics, if necessary.
The survival of cats with TCC depends on where the tumor is located in the bladder, the extent and severity of the disease, whether metastasis has already occurred, and what treatments have been administered. Survival times of affected cats can range from several weeks to more than a year.
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