Prostate Gland Cancer in Dogs
I periodically force myself to write about one of a handful of diseases I truly despise, and canine prostate gland cancer definitely falls into this category. Why do I dislike this disease so much? There is no cure for it and, for as long as I’ve been alive, there remains no effective treatment that consistently keeps it at bay for a significant length of time while preserving quality of life.
The only good news about prostate gland cancer is that it is relatively rare, accounting for 0.67% of all reported malignancies in dogs. And, it is far less common than the other far more treatable forms of prostate gland disease such as bacterial prostatitis, cystic disease, and benign prostatic hyperplasia.
Behavior of prostate gland cancer
The most common form of cancer within the prostate arises from its glandular cells and is called adenocarcinoma. Transitional cell carcinomas are less common than adenocarcinomas. They arise from transitional cells that line the urinary tract.
Prostate gland cancer is a disease primarily of middle-aged and older, large breed dogs. It occurs most commonly in neutered male dogs. This is a bit counterintuitive and we used to believe just the opposite, so I will state this fact again. Prostate gland cancer is more likely to occur in dogs who have been neutered.
Invariably, prostate gland cancer is a very aggressive disease. Not only does it expand within the prostate gland, it readily spreads (metastasizes) to other sites in the body beginning with local lymph nodes and then moves on to the lungs, abdominal organs, and/or bones.
There are often no symptoms whatsoever until the prostate gland becomes significantly enlarged and/or painful. Common symptoms include:
Straining to urinate
Straining to have a bowel movement
Bowel movements that are “ribbony” or small in diameter
Hind end/back stiffness
Hind leg lameness
Blood in the urine
Abnormal discharge from the prepuce
If there is a secondary bacterial infection within the prostate gland, symptoms can include fever, lethargy, loss of appetite, and vomiting.
The diagnosis may be suspected based on clinical signs and palpation of a large, irregularly shaped, prostate gland that may be painful for the dog. Urine and blood testing are routinely performed as part of the diagnostic workup. A definitive diagnosis relies on biopsy samples collected from the prostate gland. Biopsies are typically collected using ultrasound guidance.
Once the diagnosis of prostate gland cancer is confirmed, other tests are commonly performed to determine the extent of metastasis. This process is referred to as “cancer staging.” Such testing usually involves imaging studies such as ultrasound evaluation, radiographs, and CT (computed tomography) scanning.
Treatment and prognosis
Effective treatment options for dogs with prostate gland adenocarcinoma are pretty much nonexistent. Neither chemotherapy nor surgery provides significant benefit. Radiation therapy is of limited value. Chemotherapy can provide temporary relief of symptoms for some dogs with transitional cell carcinoma. For most dogs with prostate gland cancer, treatment is primarily palliative, aimed at reducing the discomfort associated with the disease and enhancing quality of life.
Ultimately, the cancer-related symptoms become life limiting. It is at this point that either euthanasia or intensive hospice care is indicated.
Have you ever had or known a dog with prostate gland cancer?
Nancy Kay, DVM
Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
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Please visit http://www.speakingforspot.com to read excerpts from Speaking for Spot and Your Dog’s Best Health. There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at http://www.speakingforspot.com, Amazon.com, local bookstores, and your favorite online book seller.