Prostate Disorders in Dogs

Laurie Anne Walden, DVM

Photo by Jonny Neuenhagen on Unsplash

The prostate gland grows and develops in response to testosterone and related male sex hormones. Almost all prostate disease that we see in companion animal practice is in intact (not neutered) dogs.
 
In male animals, neutering means surgical removal of the testicles (castration). Some prostate diseases can affect neutered animals, but these are rare. Most pet male cats in the United States are neutered, so prostate disease is much less common in cats than in dogs.
 
Benign Prostatic Hyperplasia
Because the prostate can keep growing as long as it’s exposed to testosterone, most intact male dogs eventually develop enlargement of the prostate, or benign prostatic hyperplasia (BPH). About half of intact male dogs have microscopic evidence of BPH by the time they’re 4 years old; more than 90% have it by the time they’re 8.
 
Most dogs with BPH have no signs of the condition and don’t need treatment. Signs can include blood in the urine, straining to urinate or defecate, and constipation. BPH can reduce the fertility of breeding dogs.
 
In some dogs, an enlarged prostate can be detected with rectal palpation. Ultrasonography is used to measure the prostate and make the diagnosis. Depending on the dog’s signs and test results, samples of prostate fluid or prostate cells might be sent to a laboratory to rule out other prostate disorders.
 
For dogs whose prostate enlargement is causing a problem, the treatment is to eliminate exposure to testosterone, typically with castration. Medications that block the effects of testosterone on the prostate are available for breeding dogs that need to keep their testicles.
 
Prostatitis
Dogs with BPH are prone to develop prostatitis, which is infection of the prostate. Prostatitis is fairly common in intact male dogs and rare in neutered male dogs. The signs of prostatitis depend on whether the condition is acute (has just begun) or chronic (has been going on for a long time):

• Acute prostatitis: pain (might seem like lower back pain or belly pain), fever, decreased energy, decreased appetite, blood in the urine, or straining to urinate or defecate; usually quite painful on rectal palpation
• Chronic prostatitis: possibly no signs at all, less likely to be painful; possibly blood in the urine, dribbling urine or fluid from the penis, or other signs of urinary tract infection

 
Prostatitis is suspected in any intact male dog with compatible signs—especially if rectal palpation is painful—or repeated urinary tract infections. Diagnostic tests include blood tests, urinalysis, ultrasonography of the prostate, and culture of prostate fluid. Some dogs with prostatitis also have abscesses of the prostate, and these can be seen with ultrasonography.
 
The treatment for prostatitis is several weeks of antibiotics along with treatment of the underlying BPH, which means castration for most dogs. Dogs that are ill with acute prostatitis sometimes need to be hospitalized. Abscesses of the prostate might require surgical drainage.
 
Prostate Cancer
Prostate cancer is rare but unfortunately very serious in dogs. The types of prostate cancer that dogs get aren’t linked to testosterone level, so castration does not protect dogs against prostate cancer (it’s actually more common in neutered dogs for unknown reasons). The screening tests and treatments for prostate cancer that are used in men don’t work in dogs. Prostate cancer in dogs tends to be aggressive, is metastatic (spreads through the body), and is usually diagnosed at a late stage. Treatment options other than palliative care are limited; a veterinary oncologist is the best source of advice for an individual dog.
 
Sources
Christensen BW. Canine prostate disease. Vet Clin North Am Small Anim Pract. 2018;48(4):701-719. doi:10.1016/j.cvsm.2018.02.012
Palmieri C, Fonseca-Alves CE, Laufer-Amorim R. A review on canine and feline prostate pathology. Front Vet Sci. 2022;9:881232. doi:10.3389/fvets.2022.881232

Image source: https://unsplash.com/photos/black-and-white-short-coated-dog-tKtYHZ13yls

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