By Christie Long
I talk a lot about the importance of routine health screenings for the presence of disease in apparently healthy animals. One of the diseases we’d most like to detect early is cancer, because often early intervention can save or prolong an animal’s life.
Bloodwork is important, but the picture is not complete without a urinalysis. In terms
of screening for cancer a urinalysis is an invaluable tool for detecting a fairly
common type of cancer in dogs known as transitional cell carcinoma of the bladder.
Often abbreviated “TCC”, this cancer arises from the unique skin cells that line the
urinary tract, called transitional epithelial cells. Like most cancers, we don’t
specifically know what causes TCC, but chronic inflammation such as that caused by frequent urinary tract infections may play a role.
A simple urinalysis becomes very important to early detection of TCC. A normally
voided urine sample (i.e., one that is collected from the stream while a dog is
actively urinating) should not contain red blood cells. Owners might say, well, my dog’s urine doesn’t look like it has blood in it, so everything must be OK, right? The
answer is maybe, or maybe not. There is blood you can see in urine and blood that
exists in such small quantities can only be detected with a urinalysis. Neither kind
should be present in a normally-voided sample.
Blood in urine doesn’t usually mean cancer. Urinary tract infections are the most
common reason why this happens in dogs. Urinary stones can also be present. But if
transitional epithelial cells are discovered in urine, this is cause for further investigation. Infections and stones can cause transitional cell shedding, but if neither of these is present the transitional cells found in the urine should be examined by a pathologist to determine if they look like malignant cells. If malignancy is suspected, ultrasound examination of the bladder and kidneys is the next step to determine if a mass is present. Sometimes cells can be taken from the mass with a needle and a definitive diagnosis can be made.
Depending on the location of the tumor, surgery is often considered to remove as much of the tumor as possible. Unfortunately these tumors are often present in areas that makes surgery
challenging, due to the need to maintain the function of the ureters (the tubes that
lead to the kidneys) and the urethra (the tube that leads from the bladder out of the
Chemotherapy for TCC is typically very well-tolerated, and can restore normal urinary function and slow tumor growth for some time. Again, early detection of this cancer is important, so that surgery and/or chemotherapy can provide the best possible outcomes.
Christie Long is a veterinarian at the VCA Animal Hospital in Fort Collins, CO. Long left her job in software sales in 2000 to travel for 13 months. Along the way, she was touched by the plight of the animals she saw and somewhere in the Nepalese Himalayas she vowed to return to school to become a veterinarian. While she often finds end-of-life situations heart-wrenching, she considers herself blessed to be called upon as a trusted adviser to families during difficult times. Dr. Long’s family includes her husband and travel partner, Wiley, their son, Wiley IV, their dogs Pancake and Gizmo and cats Sneaky and Sidh.