The prostate is a gland in males that surrounds the urethra at the neck of the bladder. It is responsible for producing fluids that provide nutrients to the sperm and assist the movement of the sperm.
Prostate cancer is not common in dogs (amounts to about 0.2 to 0.6 percent of all canine cancers), but it is an aggressive form of cancer and is often fatal.
Canine prostate cancer is not influenced by testosterone and as such it can affect all male dogs, whether they are neutered or not. Neutering does not protect a dog from developing prostate cancer. In fact, in a 2007 study, it was found that neutered dogs had a higher risk of developing prostate cancer than intact ones.
Carcinoma (e,g. prostatic adenocarcinoma) is the most common form of prostate cancer. It is a highly aggressive and invasive form of cancer. Carcinoma can spread (metastasize) rapidly to other sites in the body, such as the lymph nodes, bones and lungs.
Neutering does not protect a dog from developing prostate cancer.
Causes of Canine Prostate Cancer
The exact cause of prostate cancer in dogs remains unknown. As mentioned above, this form of cancer is testosterone-independent, so it happens to both neutered and intact male dogs with similar frequency.
Prostate cancer is not breed specific either. It can occur to all breeds of dogs, and it occurs more frequently in older dogs.
Symptoms of Canine Prostate Cancer
Prostate cancer is one condition that causes prostate enlargement.
An enlarged prostate presses against the wall of the urethra, making it very difficult for the affected dog to urinate. The dog also shows the following symptoms:
- Frequent urination
- Straining to urinate
- Blood in urine
- Blood or pus can be seen dripping from the penis
In addition, prostate cancer can cause a dog to walk in an abnormal gait. The rear legs look stiff and the dog takes very small steps. This is due to the effect of the cancer on the dog’s bones.
The affected dog may also suffer from constipation and/or difficulty defecating. Other possible symptoms include fever and lethargy.
How is Canine Prostate Cancer Diagnosed?
Diagnosis of prostate cancer in dogs is not easy since, unlike humans, dogs do not produce prostate specific antigens (PSA). These are markers that can be used to identify prostate tissue.
Instead, dogs produce canine prostate specific esterase (CPSE).
The problem is, CPSE does not allow easy diagnosis since it is difficult to determine the origin of the cancer. That is, it doesn’t show if the cancer started in the prostate or somewhere else in the body but has spread to the prostate.
Diagnosis involves the use of urinalysis, X-rays and abdominal ultrasound to check for abnormalities in the prostate.
If the vet suspects a dog has prostate cancer, he will do a biopsy of the rectal wall to get a definitive diagnosis.
Conventional Treatment of Canine Prostate Cancer
Conventional treatment options are limited and not too effective.
Neutering a dog with prostate cancer does not stop the cancer from developing and spreading.
Removal of the prostate surgically can cause numerous complications such as urinary incontinence, so surgery is usually not an option.
Only chemotherapy and sometimes radiation can be used to try to shrink the cancer. Unfortunately, these treatments are far from effective and they seldom extend the dog patient’s life for too long.
Prostate cancer in dogs is aggressive and invasive with a fast rate of metastasis. As such, it carries an extremely poor prognosis.
Because canine prostate cancer is not usually detected and diagnosed until at its later stage, the average life expectancy is approximately thirty days after diagnosis.