Prostate Enlargement in Dogs

What Is Prostate Enlargement in Dogs?

The prostate of a male dog is a gland that envelops their urethra, the tube that carries urine from the bladder to outside the body. The gland is situated near the start of the urethra after it exits the bladder. Like its function in human males, the prostate in male dogs develops most of the fluid component in semen.

A prostate may become enlarged due to infection, masses, or other causes. When this occurs, the dog may develop other problems due to the prostate’s proximity to important anatomical structures like the urethra, bladder, and rectum.

The enlarged prostate can compress the urethra, which can make urination difficult. If the prostate is large enough to put pressure on the rectum, the dog may strain to defecate. In unneutered dogs, prostate enlargement has repercussions for fertility.

Not all causes of prostate enlargement are linked to cancer. The most common cause of an enlarged prostate is benign, meaning it’s not cancerous.

Symptoms of Prostate Enlargement in Dogs

• Straining to urinate or defecate

• Frequent urination

• Blood in urine

• Increased drinking

• Pain in the abdomen, which may cause the dog to vocalize when pressure is placed on the abdomen

Causes of Prostate Enlargement in Dogs

Several conditions cause prostate enlargement in dogs, including: benign prostatic hyperplasia (BPH), prostatic infections (prostatitis), and prostate cancer.

Hyperplasia is the enlargement of an organ or tissue caused by increased replication of cells. With benign prostatic hyperplasia, male hormones cause increased production of cells, which results in prostate enlargement.

While BPH is considered a normal age-related change in intact male dogs, it can cause issues for the dog if the prostate becomes too large or if the prostate develops cysts. Prostatic cysts can lead to infection of the prostate.

Benign prostatic hyperplasia is the most common cause of prostate enlargement in male dogs who have not been neutered. Breeds with an increased risk of BPH include Scottish Terriers, German Shepherds, and Doberman Pinschers.

Prostate infection usually occurs due to bacteria that make their way to the prostate through the urethra. The risk of developing prostatitis is increased in older unneutered male dogs with BPH. Large-breed dogs are more predisposed to prostate infection than small-breed dogs.

Prostate cancer can develop in both neutered and unneutered dogs. Dogs are typically older at the time of diagnosis, with most diagnoses occurring between 8.5 and 11 years of age. Breeds predisposed to prostate cancer include:

• Bouvier des Flandres

• Doberman Pinschers

• Shetland Sheepdogs

• Scottish Terriers

• Beagles

• Miniature Poodles

• German Shorthaired Pointers

• Airedale Terriers

• Norwegian Elkhounds

How Veterinarians Diagnose Prostrate Enlargement in Dogs

Based on the clinical signs your dog has been exhibiting, your veterinarian will begin with a physical exam. This will include palpating (examining by touch) the abdomen and performing a rectal exam to feel the prostate.

Your veterinarian will run bloodwork to look at your pet’s overall health. Examining the pet’s urine and culturing it for bacteria may also help determine if your pet has a prostate infection.

X-rays and ultrasound of the abdomen allow the veterinarian to further examine the size and shape of the prostate, as well as to see if there are cysts present.

In some cases, particularly if there is concern of prostate infection and the dog isn’t neutered, the veterinarian may want to perform an evaluation of the pet’s semen to look for evidence of infection or to culture for bacteria.

For a definitive diagnosis, the veterinarian may collect a sample of cells from the prostate. Some veterinarians prefer to do this with a needle and ultrasound guidance, while others prefer a biopsy obtained surgically.

If cancer is suspected, a computed tomography (CT) scan may be recommended to monitor spread of the cancer and plan treatment.

Treatment of Prostate Enlargement in Dogs

Treatment depends on the underlying cause of prostate enlargement.

For dogs with BPH, having your dog neutered is the first-choice treatment. The prostate inflammation will reduce by more than 50% within three weeks and more than 70% in nine weeks. For breeding dogs or dogs for whom anesthesia is a significant risk, treatment with oral medicines like finasteride can be given long-term to manage the condition.

For dogs with a prostate infection, the use of antibiotics should be based on urine culture results. In some dogs with an enlarged prostate, especially those who developed an infection secondary to BPH, neutering may be recommended. Antibiotics for a prostate infection are given for at least four to six weeks. Common choices include enrofloxacin, trimethoprim-sulfonamide (TMS), clindamycin, and erythromycin.

Prostate cancer has at least an 80% chance of spreading (metastasizing) to other parts of the body. Because of this, most pet parents prioritize quality of life over aggressive treatment. Animals who have evidence of metastases or advanced disease at the time of diagnosis are not good candidates for curative treatments.

Treatment options for prostate cancer in dogs include:

• Oral medications like piroxicam that reduce inflammation and slow tumor growth

• Chemotherapy

• Radiation therapy

• Surgery to remove part of or the entire prostate

Some treatments simply focus on relieving obstructions. Specialty hospitals may be able to place a stent in the urethra to help the dog urinate. Stool softeners like lactulose or polyethylene glycol (MiraLAX®) are often prescribed to help with constipation.

Recovery and Management of Prostate Enlargement in Dogs

Recovery and management also depend on the underlying cause and severity of the disease.

For dogs with symptoms of prostate enlargement due to BPH, neutering is curative. Your dog should recover within a few weeks.

Dogs with a prostate infection that came on suddenly usually have successful antibiotic treatment without neutering, while dogs with chronic infection of their prostate usually need to be neutered to completely resolve their signs.

Treatment for a prostate infection lasts one to two months. Dogs that have a fever and other symptoms may need to be hospitalized short-term for supportive care. Supportive care would include intravenous (IV) fluids, nutritional management, pain medications, and possibly a urinary catheter to ensure urine can drain. Your pet may receive their antibiotics and other medications through an IV catheter.

Dogs with advanced prostate cancer that do not receive treatment are typically humanely euthanized within a month, due to the severity of the disease. Dogs treated with oral medications, radiation, and/or chemotherapy have a prognosis closer to seven months.

Surgery is not typically pursued for dogs with prostate cancer. Management is focused on comfort, pain relief, and ensuring that they can urinate and defecate.