Transitional cell carcinoma (TCC) is the most common canine tumor of the bladder and urethra. At this time, the cause of transitional cell carcinoma is not known. Exposure to carcinogenic compounds is suspected to be a contributing factor, but very few specific agents have been identified. TCC is seen more commonly in female dogs than males. Certain breeds, including Scottish terriers, West Highland White terriers, Airedales, Collies, Shelties, and Beagles, appear to be predisposed.
Most dogs present initially with symptoms similar to a urinary tract infection (straining to urinate, frequent urinations, bloody urine). In fact, many dogs will temporarily improve with antibiotics.
Your veterinarian may palpate a mass in the pet’s caudal abdomen or urethra during a physical examination. A urine sample can be evaluated for a specific glycoprotein complex with the V-BTA test. But it is important to note that this is a screening test and there are sometimes false positive results, especially if the dog has a urinary tract infection. Contrast radiography and abdominal ultrasonography usually identify a mass in the bladder or urethra. To definitively diagnose transitional cell carcinoma, an evaluation of a biopsy or cytologic sample by a pathologist is required.
As with most tumors, the initial treatment for transitional cell carcinoma in dogs is wide surgical removal. However, the tumor is frequently found in an area that is difficult to excise or is more extensive than can be assessed clinically. Therefore, surgery rarely will cure dogs with TCC. A surgical “debulking” procedure may improve the survival time of dogs with TCC. This procedure will be explained with you if it is believed to be an option for your pet.
When wide surgical removal is not a viable option, radiation therapy can be used for local tumor control since we can often irradiate a larger area than a surgeon can remove. Radiation therapy has been used in humans for decades to control urinary tract tumors. At MedVet, we have frequently treated bladder and urethral tumors with radiation therapy when surgical removal is not possible. Both improvement in clinical symptoms and a decrease in tumor size are often observed in dogs treated with radiation therapy.
Chemotherapy has also been used to treat the disease in the pet’s lower urinary tract and to slow the progression of metastatic cancer. The reported median survival times with chemotherapy treatment range from 130-320 days. Transitional cell carcinomas are relatively resistant to chemotherapy; therefore, it is best used as an adjunctive treatment. Some of the chemotherapy agents used to control TCC can also act as radiation sensitizers; therefore, if given in conjunction with radiation, we can increase the cancer killing effects of the radiation. The dose of chemotherapy needed to achieve the radiosensitizing effect is much lower than the standard chemotherapy dose.
Nonsteroidal anti-inflammatory drugs (NSAIDS) have potential anti-cancer effects and have been shown to be beneficial for dogs with TCC. At this time, a combination of aggressive local control (surgery or radiation therapy), chemotherapy, and NSAIDs is the recommended treatment for dogs with lower urinary tract tumors.