Urethral Cancer in Dogs

Urethral cancer in dogs is an uncommon type of cancer. It affects the squamous epithelium, the membrane that covers the urethra. Read on to learn more about this type of cancer in dogs.

Causes and Risk Factors for Canine Urethral Cancer

Vets don't know exactly what causes urethral cancer in dogs, but they think it might have something to do with carcinogens in the environment. Some medications, especially those administered to treat autoimmune disorders, may produce carcinogenic compounds when metabolized by the liver. These carcinogens then pass through the bladder and urethra, and may cause cancerous mutation of the epithelial cells of the urethral membrane.

Middle-aged and geriatric dogs are more prone to this condition, especially if they are female. Certain breeds, such as Boston Terriers and English Bulldogs, may be more prone to it than others. 

Symptoms of Urethral Cancer in Dogs

Dogs with urethral cancer may exhibit some or all of the following symptoms:

  • Bloody urine
  • Blood dripping from the urethra, whether or not the dog is currently urinating
  • Excessive licking of the genital area
  • Excessive frequency of urination
  • Painful urination 
  • Slow urination

Urethral cancer, like most other forms of cancer, can spread to other parts of the body. Symptoms that indicate your dog's cancer may have spread include:

  • Difficulty breathing
  • Coughing
  • Straining to move the bowels
  • Loss of appetite
  • Lethargy

Diagnosing Cancer of the Urethra in Dogs

Your vet will need to perform a complete physical exam in order to diagnose urethral cancer, and he'll also need your dog's complete medical history. There are other conditions that can cause symptoms similar to those of urethral cancer. These conditions include urethral prolapse, in which the urethral lining protrudes into the urethra. Your vet will need to perform blood tests and may also take X-rays, ultrasounds and biopsies to confirm the presence of a cancerous tumor and rule out urethral prolapse.

Treating Cancer of the Urethra in Dogs

The most common treatment for urethral cancer involves surgical removal of the tumor and some of the healthy tissue surrounding the tumor. Removal of healthy tissue helps ensure that the tumor won't come back. 

In addition, your vet will probably also recommend chemotherapy or radiation therapy to help keep the cancer from coming back. If your dog's cancer has already spread to other parts of his body, surgery may not be helpful. Chemotherapy and radiation treatment can slow or stop the growth of cancerous tumors, relieve some of your dog's symptoms and extend his life.

Some vets may administered non-steroidal anti-inflammatory drugs (NSAIDs) to treat the pain and inflammation associated with urethral cancer. Some studies suggest that administered NSAIDs such as prioxicam can help bring urethral cancer into remission.

Prognosis for Canine Urethral Cancer

With treatment, your dog may survive for six months to one year after diagnosis. The prognosis is better if your dog's cancer has not yet spread at the time of diagnosis. Urethral cancer has already spread by the time of diagnosis in about 20% of cases. Urethral cancer spreads to other parts of the body in at least half of all cases.