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Canine Transitional Cell Carcinoma (Bladder Cancer) FAQ — Key Information for Pet Owners

Oncology/CancerQ&AMeongsiljang Veterinary Advisory Board

Canine transitional cell carcinoma is a malignant tumor that develops in the bladder. Its early symptoms are often vague, making it easy for pet owners to overlook. Early diagnosis and treatment are crucial in determining survival rates.

What is Canine Transitional Cell Carcinoma (Bladder Cancer)?

An image of a dog diagnosed with bladder cancer sitting with its veterinarian.

Canine transitional cell carcinoma (TCC) is a malignant tumor that arises from the transitional epithelial cells lining the bladder. It is the most common bladder tumor in dogs and typically develops in the trigone, where the ureters meet the urethra. This condition primarily affects middle-aged to older dogs, with reported cases showing a higher prevalence in females. Early symptoms are often subtle, making them easy for pet owners to overlook. - Characteristics of TCC: In the early stages, symptoms may be mild, such as increased urination frequency or small amounts of blood in the urine. As the cancer progresses, dogs may experience difficulty urinating, severe pain, and even an inability to pass urine. - Importance of Early Diagnosis: Visiting the vet while symptoms are still mild allows for easier diagnosis and management, helping to maintain your pet’s quality of life. - High-Risk Groups: Older dogs and breeds known to have a higher risk of TCC, such as Shetland Sheepdogs, require particular attention. Early detection and appropriate treatment are key to preserving your dog’s quality of life.

What are the main causes of transitional cell carcinoma?

While the exact cause of transitional cell carcinoma remains unclear, genetic factors and chronic irritation of the bladder are believed to play a role. In fact, mutations in the BRAF gene have been identified in many dogs diagnosed with this cancer, highlighting the involvement of genetic predisposition in its development. Additionally, prolonged chronic infections or inflammation can lead to abnormal proliferation of the bladder lining (urothelium), potentially resulting in tumor-like changes. Extra vigilance is needed in older dogs and breeds known to be at higher risk, such as Shetland Sheepdogs. However, since it is difficult to pinpoint a specific cause in most cases, early detection is more crucial than prevention.

Microscopic image showing the cellular structure of transitional cell carcinoma

What are the main symptoms of transitional cell carcinoma?

The most common signs of transitional cell carcinoma in dogs are urinary difficulties and blood in the urine. Specifically, you may notice pain during urination, frequent attempts to urinate, decreased urine volume, or interrupted urine flow. Blood in the urine can appear red or brown, and in some cases, it may not be visible to the naked eye, with red blood cells only detectable through a urinalysis. Other symptoms may include weight loss, lethargy, and discomfort in the lower abdomen (bladder area). If these symptoms persist, it is essential to consult your veterinarian.

Signs requiring immediate veterinary visit

If your dog is unable to urinate, shows severe pain during urination, has worsening blood in the urine, or experiences a sudden increase in urination frequency, you should go to the vet immediately. The tumor may be blocking the urethra, causing urethral obstruction, and if urine cannot be properly expelled, it can lead to postrenal uremia, where waste products accumulate behind the kidneys. In particular, if your dog is completely unable to urinate, this is a life-threatening emergency, so it is essential to visit the vet without delay.

How is it diagnosed?

Transitional cell carcinoma is accurately diagnosed through a combination of tests. - Urinalysis and urine cytology: The presence of blood in the urine or abnormal urothelial cells may raise suspicion of cancer. - Imaging studies, such as bladder ultrasound: These are fundamental imaging tests used to determine the tumor’s size and location. - Cystoscopy (endoscopy): This allows direct visualization of the bladder’s interior and enables biopsy of the tumor site. - Cellular and tissue biopsy: This is the key procedure for confirming the presence and nature of cancer, typically performed via cystoscopic biopsy. - Urine BRAF gene test: This is an adjunctive test that detects BRAF mutations, which are found in a significant proportion of dogs with transitional cell carcinoma, through urine analysis. An accurate diagnosis is the first step toward effective treatment.

A veterinarian performing an ultrasound examination on a dog's bladder

What are the treatment options?

Treatment for transitional cell carcinoma involves medication (anti-inflammatory drugs and chemotherapy), surgery, radiation therapy, or a combination of these approaches. When the tumor is localized, surgical options such as partial cystectomy (removal of a portion of the bladder) may be attempted. For medical management, the nonsteroidal anti-inflammatory drug piroxicam is used either alone or in combination with chemotherapy. Reported response rates for piroxicam are approximately 18% when used as a standalone treatment and around 35% when combined with chemotherapy. Chemotherapeutic agents commonly used in combination include mitoxantrone, carboplatin, doxorubicin, cyclophosphamide, and cisplatin. Radiation therapy is also utilized as a treatment option. The specific treatment plan is determined by your veterinarian based on the stage of the cancer and your dog’s overall health status.

What is the prognosis and survival time?

The prognosis for transitional cell carcinoma varies significantly depending on the stage at diagnosis and the treatment approach. Studies have shown that when debulking surgery alone is performed, the median survival time is approximately 109 days, whereas combining debulking surgery with nonsteroidal anti-inflammatory drugs (NSAIDs) such as carprofen or piroxicam has been reported to extend this to about 380 days. There are also cases of survival up to 580 days with a combination of surgery and chemotherapy, and the median survival time for metronomic chlorambucil therapy is approximately 221 days. Piroxicam alone showed a response rate of about 18%, which increased to approximately 35% when combined with chemotherapy. Since individual outcomes can vary widely, it is important to manage your pet’s condition through regular follow-up examinations in close collaboration with your veterinarian.

Comparison of treatment options: Surgery vs. Chemotherapy vs. Combined therapy

Item	Suitable stage	Effect	Side effects
Surgery	Localized tumors	Median survival of about 109 days with cytoreductive surgery alone	Difficulty urinating, hematuria, urethral stricture, etc.
Chemotherapy (drug therapy)	Possible metastasis, upon recurrence	About 18% response rate with piroxicam alone; median survival of about 221 days with chlorambucil	Loss of appetite, bone marrow suppression, etc.
Combination therapy	When the risk of metastasis is high	About 35% response rate with piroxicam + anticancer drug; a case of 580-day survival with surgery + anticancer drug	Possible drug and surgical side effects such as bone marrow suppression

The treatment choice should be decided after consulting the veterinarian, based on the cancer stage, the dog's health condition, and the owner's circumstances.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

My dog urinates frequently but only passes small amounts. Could this be bladder cancer?

Yes, frequent urination with small amounts or interrupted flow is a classic sign of bladder cancer. The bladder may become narrowed due to the tumor, or pain may prevent proper urination. Immediate veterinary care is necessary.

Can transitional cell carcinoma be cured?

While a complete cure may be difficult, early diagnosis and appropriate treatment can significantly extend your pet’s lifespan. The goal is to control the tumor through surgery or chemotherapy, alleviate pain, and maintain a good quality of life.

Can transmissible venereal tumor spread to other dogs?

No, transitional cell carcinoma is not contagious. While genetic predisposition and environmental factors can play a role, it does not spread directly to other dogs. You can manage your pet’s care with peace of mind.

Can it be prevented?

While there is no definitive preventive method, it is important to avoid chronic cystitis, ensure your pet drinks plenty of water, and undergo regular health check-ups for early detection. This is especially important for middle-aged and older dogs.

My dog has no appetite during chemotherapy. What should I do?

Loss of appetite is a common side effect during chemotherapy. Your veterinarian may recommend supportive supplements, and feeding small, frequent meals of highly palatable food can also help. If your pet’s appetite doesn’t return for an extended period, please consult your veterinarian.

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References

[1] Knott, C., Simpson, J.W., Tasker, S., et al. (2000). Transitional cell carcinoma of the urinary bladder in dogs: A retrospective study of 120 cases. Veterinary Surgery, 29(5), 421–428.

[2] Moore, A.S., Nelson, R.W., Henry, C.J., et al. (2002). Chemotherapy for transitional cell carcinoma in dogs: A retrospective study of 45 cases. Journal of Veterinary Internal Medicine, 16(3), 289–294.

[3] Withrow, S.J., Vail, D.M., & Page, R.L. (2017). Small Animal Clinical Oncology (5th ed.). Elsevier Saunders.