Prostate cancer is a looming concern for adult human males. Although diagnosed much less frequently in canine males, dogs can also be stricken with prostate cancer, which is also referred to as prostatic neoplasia.
Prostate cancer is the most serious of all prostate problems in dogs, and prostatic adenocarcinoma is the most commonly diagnosed form of dog prostate cancer. The good news is that prostatic adenocarcinoma accounts for only one percent of all malignant cancers that are diagnosed in dogs. The bad news is that it is highly aggressive, and by the time it is diagnosed, metastasis has usually already occurred in other areas of the body, including the bones, lymph nodes and lungs. Although the prostate gland’s chief roles serve to aid in reproduction, testosterone does not influence the development of prostate cancer. Therefore, neutered and intact male dogs alike are at risk for developing prostate cancer, and neutering will not cure prostate cancer. Any breed can develop prostate cancer, but large breeds are at greater higher risk. Prostate cancer typically occurs in older dogs.
Signs and Symptoms
The signs and symptoms that are observed in a dog with prostate cancer vary, depending on the stage of the disease and on the extent of metastasis that has occurred. Some signs and symptoms include any of the following:
- Difficulty urinating a steady stream
- Blood-tinged urine
- Blood dripping from the penis
- Pain when the area of the prostate is palpated
- Urinary blockage
- Decreased appetite
- Weight loss
- Weakness in the rear legs
- Straining to defecate
- Changes in the shape of stools
- Difficulty breathing once the cancer has spread to the lungs
The symptoms of dog prostate cancer develop gradually. Furthermore, the prostate normally becomes enlarged as dogs age, which can also result in changes in urination habits. If you observe any of the above signs or symptoms in your male dog, schedule an appointment with your veterinarian as soon as possible for an examination.
Your veterinarian will begin by taking a history of the symptoms that you have observed in your dog, and then he or she will perform a digital rectal examination to assess the size of the prostate gland and to feel for any abnormalities. Some additional diagnostic tests that your veterinarian will perform include:
- Laboratory tests, including a complete blood count, a chemistry profile panel and a urinalysis
- Radiographs and ultrasound images of the abdomen to evaluate the prostate gland and to determine if metastasis has occurred in the pelvic or abdominal regions
- Pathology test on biopsied prostatic tissue samples
- Radiographs of the chest to determine if metastasis has occurred in the lungs
Once these tests have been performed, the results can confirm a diagnosis and determine the extent of metastatic spread. Unfortunately, there are few options for dogs with prostate cancer.
Treatment and Prognosis
Since roughly 80-percent of diagnosed cases of prostate cancer in dogs have already undergone metastasis, surgical removal of the prostate is not a curative treatment option. Even in the rare instance in which metastasis has not yet occurred, this surgical procedure is complicated by the fact that the prostate gland is located in such close proximity to the urethra. Postoperative complications, such as long-term urinary incontinence, also make surgery an unfavorable choice for treatment.
Radiation and chemotherapy have been administered for the treatment of prostate cancer in dogs. Such treatment does not cure prostatic adenocarcinoma, but it can temporarily reduce the cancer’s effects and extend the dog’s quality of life for a few more months. Once a dog exhibits symptoms of prostate cancer, the prognosis is poor. The symptoms worsen, and urination and defecation become painful. Your veterinarian may prescribe palliative treatment in an attempt to keep your dog as comfortable as possible for as long as possible. The average life expectancy for a dog that has been diagnosed with prostate cancer and does not undergo radiation or chemotherapy is approximately one month following the time of diagnosis.