Definition

Prostatic neoplasia, also called prostate cancer, is an uncommon but extremely serious disease that occurs in both neutered and intact male dogs. Prostate tumors are highly invasive, space-occupying masses that typically have metastasized by the time they are diagnosed.

The prostate is a lobed gland in male dogs located at the junction of the bladder and the urethra. It contributes a liquid component to seminal fluid. The prostate gland increases in size and weight as a male dog ages. This is normal. The primary prostate problems in dogs are benign prostatic hyperplasia (BPH), prostatic cysts, bacterial prostate infection, inflamed prostate (prostatitis), prostatic absceses and cancer (neoplasia). Of these, BPH and prostatitis are the most common in domestic dogs. While less common, prostate cancer is among the most serious of all prostate disorders in dogs.

Causes of Canine Prostate Cancer

The most common type of prostate cancer in dogs is adenocarcinoma, which predominates in intact males or dogs that were recently neutered. Other tumor types include undifferentiated carcinoma, fibrosarcoma, leiomyosarcoma and squamous cell carcinoma; these tend to be more common in neutered dogs. Regardless of type, prostate tumors are aggressive. They typically invade surrounding tissue and are highly metastatic, commonly spreading to bone in the spine and/or pelvis and to nearby (regional) lymph nodes. They also often metastasize to the lungs.

Prevention

There is no known way to prevent prostate cancer. Because prostatic tumors are not influenced by testosterone, castration does not reduce the risk of this disease or slow its progression.

Special Notes

Surgical resection is the only viable “cure” for prostate cancer. However, since the cancer usually has metastasized by the time it is diagnosed, surgical rarely is a curative option. Radiation and chemotherapy can be used to help minimize the effects of prostate disease and to help affected dogs live as comfortably as possible for the duration of their lives. Dogs that develop clinical signs associated with prostate cancer have a guarded to grave prognosis.