Transitional cell carcinoma (TCC) is the most common type of bladder cancer diagnosed in dogs. Based on their location and/or size, tumors can block the flow of urine into or out of the bladder, which makes dogs very sick very fast. Transitional cell carcinomas also can spread out of the urinary tract, typically to the lungs and lymph nodes within the abdomen. It is important for owners to understand the symptoms associated with TCC to avoid potentially catastrophic delays in treatment.
Transitional cell carcinoma is most frequently diagnosed in older, spayed female dogs. Scottish Terriers have an especially high incidence of the disease, and in this breed, exposure to lawn herbicides has been shown to increase a pet’s risk for developing TCC. Beagles, Collies, Shetland Sheepdogs, and West Highland White Terriers are also at higher than average risk for TCC.
The most common symptoms associated with transitional cell carcinoma are straining to urinate, urinating small amounts frequently, urinary incontinence, and the presence of blood in the urine. These same clinical signs are often seen with other types of urinary tract disease, so diagnostic tests are necessary to reach a definitive diagnosis. These may include:
- urinalysis – tumor cells are sometimes detectable during a routine urinalysis. Many dogs with TCC also have a urinary tract infection.
- bladder tumor antigen test – if this urine test is negative, the chances that a dog has TCC are very low. Positive results indicate that a dog might have TCC and need to be confirmed with other tests.
- x-rays – bladder tumors can be visible on x-rays, particularly when contrast agents are infused into the bladder. Abdominal and chest x-rays are also used to screen for spread of the cancer.
- abdominal ultrasound – ultrasound is another good way to visualize tumors in the bladder and check for metastases in the abdomen.
- biopsies – tissue samples taken from the tumor and evaluated by a pathologist may be necessary to confirm the diagnosis of TCC.
Treatment and Prognosis
Because they are typically located near the area where the urethra exits the bladder, transitional cell carcinomas
are often difficult to treat surgically. Most cases of TCC are best treated with chemotherapy and/or radiation. Studies have shown that nonsteroidal anti-inflammatories like piroxicam and deracoxib have activity against TCC, so they are often used in combination with traditional chemotherapeutic agents or alone when the situation warrants. Antibiotics are prescribed when a urinary tract infection is present.
All treatment protocols for TCC should be viewed as a way to prolong a pet’s life, not as a cure. Once a dog can no longer pass urine adequately and/or its quality of life is unacceptable in any other way, euthanasia is often the best option.