Urethral Neoplasia in Dogs

The organs of the urinary section include the kidneys, urinary bladder, urethra, and ureters. These organs of the urinary tract are the most commonly affected by cancer, if the horse has a cancer diagnosis. Most of the cancers of the urinary tract, including the urethra, are known as transitional cell carcinoma.

The urethra is the narrow tube that helps urine come out of the body. In the male, it is located within the penis, and sometimes may become inflamed. This can be due to a bladder infection, a blocked urethra, or the more serious urethral neoplasia. The tip of the urethra may drop down and be visible and look as if there is an abnormal growth or tumor present. The urethra of the female is smaller than the male’s. 

Neoplasia is the new, uncontrolled growth of cells and can be either malignant (cancerous), or benign, like a cyst that is not cancerous. In urethral neoplasia in dogs, the growth is typically found to be transitional cell carcinoma, which is a malignancy. There are several different causes for urethral neoplasia in dogs, and this type of cancer in the urethra and lower urinary tract is still being researched.

Urethral neoplasia in dogs is the growth of mass cells within or on the outer part of the urethra. The growth may be either benign or malignant, although in most cases the growth turns out to be transitional cell carcinoma.

Symptoms of urethral neoplasia vary from dog to dog in severity, depending on the size of the tumor and how long it has been present. Symptoms may include:

• Frequent urination
• Vomiting
• Pain in the abdomen
• Weakness
• Lethargy
• Depression
• Unwillingness to eat
• Unwillingness to exercise
• Weakness in back legs

Types

Urethral neoplasia is a rare disorder with transitional cell carcinoma being the most common of this disease. Other types of cancer of the urethra and lower urinary tract include:

• Squamous cell carcinoma
• Leiomyosarcoma
• Hemangiosarcoma
• Fibrosarcoma
• Hemangiosarcoma
• Osteosarcoma

Urethral neoplasia usually occurs when dogs are 9-10 years old. As for predisposition, there are some breeds that are more susceptible to contracting this disease. Causes of this condition include:

• Predisposition 
• Genetics
• Environmental exposure to pesticides
• Exposure to lawn herbicides and chemicals

If you suspect your dog has urethral neoplasia or is exhibiting any of the symptoms above, make an appointment with your veterinarian. Once you take your companion to the veterinarian, he will ask you more questions about his symptoms. He will then take blood work, a urinalysis, and a biochemistry profile. These will be preliminary tests, as there will be several more for the veterinarian to come to a definitive diagnosis.

The veterinarian will perform several clinical tests, such as palpation of the bladder, to check for a distended bladder. He may also palpate the rectal part of the urethra (the pelvic portion) may identify a mass. Often, a vaginal examination of a female dog may detect a mass.

In terms of laboratory findings, in addition to the biochemistry profile and urinalysis, the veterinarian may perform cytology and histopathology tests. These tests differentiate between benign and malignant tumors, and also communicate with the veterinarian the specific types of cancer your companion may have. 

A test to find urethral masses is called a urethrography, which the veterinarian may prefer to perform before the other tests. A radiography, a fine detector of any metastatic abnormality in the lower vertebrae and lower region of the body may be also performed. 

Your veterinarian may have other options for testing or any other diagnostic measures for your dog. Of course, the definitive diagnosis comes from a biopsy of the mass, or tumor. Once it is determined he has urethral neoplasia, treatment methods will begin.

Once your dog is diagnosed with urethral neoplasia, or cancer of the lower urinary tract, your veterinarian will present you with a variety of treatment options. Treatment methods may include:

Surgical Removal

If possible, the most successful type of therapy of urethral neoplasia is removal of the tumor itself. The most common type of cancer that occurs in urethral neoplasia, transitional cell carcinoma, typically occurs at the base of the bladder or within the urethra. In these cases, the veterinarian may suggest major reconstructive surgical procedures of your dog’s lower urinary tract.

Radiation Therapy

Radiation therapy may be given, either in isolation or in conjunction with chemotherapy medications. Whether your dog will benefit from radiation or not depends on the position of the tumor and if it has metastasized.

Chemotherapy

Common chemotherapy drugs include vinblastine, cisplatin, doxorubicin, chlorambucil, and piroxicam. There are other types as well, and your veterinarian will suggest which ones, either alone or in combination, will be the best options for your dog.

Antibiotics

If your dog has surgery to remove the tumor, your veterinarian may prescribe antibiotics to prevent infection. Even with the chemotherapy and radiation, your dog may be susceptible to developing a urinary tract infection. Antibiotics will help keep any infections away or help treat any infections that he may already have.

If your dog has been diagnosed with urethral neoplasia, is important to try to stay positive for you and him alike. Typically, urethral neoplasia in the form of transitional cell carcinoma has a prognosis of poor; however, it is important to understand that your veterinarian will do his very best to treat your dog throughout his illness. Unfortunately, even with surgery, radiation, and chemotherapy, recurrence of the tumors can occur as well as becoming metastasized. Is important to take it day by day, and enjoy each day with your companion.

When your dog is undergoing any type of therapy, namely radiation or chemotherapy, your veterinarian will give you specific instructions on how to care for him between treatments. He will also alert you to any side effects that your dog may experience.

If your dog has had surgery to remove the tumor, your veterinarian will also give you instructions on how to care for him post-surgery. He may prescribe an antibiotic, and will give you the information you need in terms of dosage. 

Your veterinarian will also give you advice on how to care for your dog during this time. Depending on your dog’s prognosis, he will explain to you what you may experience in terms of new behaviors, and he will also be specific with you on what you can and cannot do with him in terms of diet, any exercise, and any other lifestyle routines.