Overview of Prostatic Tumors in Dogs
Prostatic tumors or prostatic neoplasia is cancer of the prostate gland. All tumors of the prostate gland should be considered malignant, as there has not been a report of a benign prostatic tumor. The most common tumor of the prostate is prostatic adenocarcinoma. Transitional cell carcinoma is also seen.
The incidence of prostatic disease is fairly low in dogs, and very rare in cats. The cause of prostatic neoplasia is unknown.
Prostatic cancer may affect any breed of dog, but is usually seen in older (average age is about 9-10 years old), medium to large breed dogs. It only occurs in male animals. Castrated male dogs and intact (non-neutered) male dogs are equally as likely to get prostatic cancer.
What to Watch For
Sign of prostatic tumors in dogs may include:
Diagnosis of Prostatic Tumors in Dogs
Treatment of Prostatic Tumors in Dogs
Home Care and Prevention
Since most prostatic tumors have a poor response to treatment and a short survival time, the most important part of home care is keeping your pet comfortable. If your pet is painful, analgesics (pain medications) may be used. Both nonsteroidal anti-inflammatory (aspirin-like) drugs and narcotics may be used.
Stool softeners may be used if there is significant straining to defecate or constipation. If your dog is undergoing chemotherapy, periodic blood tests and recheck evaluations may be required.
There is no prevention for prostatic tumors. Neutering a dog at a young age has not been shown to decrease the incidence of prostatic tumors.
In-depth Information on Prostatic Tumors in Dogs
Prostatic neoplasia is a very aggressive type of cancer. It is quick to metastasize (spread), and has often done so by the time the diagnosis is reached. It commonly metastasizes to the lymph nodes under the lower lumbar area of the back near the pelvis, the bones of the lower lumbar vertebra and pelvis, the liver or the lungs. The disease is equally prevalent in both intact and neutered dogs, but seems to be more aggressive in neutered animals. In either case, the tumor is very serious and has a poor prognosis.
The location and anatomy of the prostate is important in understanding the clinical signs associated with prostatic neoplasia. The prostate is located just behind the urinary bladder and under the colon. The prostate encircles the urethra (tube that carries urine from the bladder through the penis and out of the body) as it exits the bladder. The prostate is made up of two symmetrical parts, or lobes, located on either side of the urethra. When the prostate is small it sits within the pelvic canal, but as it increases in size, it moves forward into the abdomen. The prostate can usually be palpated through the rectum, by digital examination. Most dogs with prostatic tumors have an asymmetrical enlargement of one of the prostatic lobes, or have palpably firm nodules. The prostate may or may not be painful.
As the tumor grows it may compress the colon causing straining to pass stool or constipation. The tumor can also invade the urethra, causing bloody urine and straining to urinate. If the cancer has spread to the bones of the lower back or pelvis, back pain and pelvic weakness may be noted.
It is very important to note whether a dog is intact or neutered, as the normal size of the prostate gland in an intact dog would be considered abnormal in a neutered dog. The most common cause of prostatic enlargement in the neutered dog is a tumor. In intact dogs there are a variety of likely causes of prostatic enlargement. Diseases that may cause similar clinical signs as prostatic tumors include: