Definition of Prostate Cancer
Prostatic cancer is a very serious disease that occurs in both neutered and unneutered male dogs. Prostate tumors are highly invasive, space-occupying masses that usually have metastasized by the time they are diagnosed.
How Prostate Cancer Affects Dogs
Prostate cancer can affect male dogs of all breeds, whether intact or neutered, and normally is diagnosed in older dogs. Signs of prostate cancer mimic the signs of other prostate disorders. They usually come on gradually, although affected animals may exhibit some or no clinical signs of disease. Most often, they will urinate frequently and in small amounts, will strain to urinate and defecate, may be constipated and may have blood in their urine. They commonly have an abnormal discharge from their penis as well. As the disease advances, dogs may develop hind end lameness and increasing pain. Affected dogs often become lethargic, with little interest in playing or eating. They may have intermittent fever and dramatic weight loss to the point of emaciation. Ultimately, almost all prostatic tumors will metastasize if untreated.
Causes of Canine Prostate Cancer
The most common cause of prostate cancer in dogs is adenocarcinoma, which seems to predominate in unneutered animals. Other reported tumor types include undifferentiated carcinoma, fibrosarcoma, leiomyosarcoma and squamous cell carcinoma, which tend to be more common in neutered dogs. Regardless of type, prostate tumors invade surrounding tissue and commonly spread to bone, lungs and regional lymph nodes.
Preventing Prostate Cancer in Dogs
There is no known way to prevent prostate cancer. Castration does not reduce the incidence of this disease.
Special Notes
Surgery is the only viable “cure” for prostate cancer, assuming that it has not spread, which it typically has by the time it is diagnosed. If surgical correction is not an option, radiation and chemotherapy are available to help minimize the effects of prostate disease and help affected dogs live as comfortably as possible for the duration of their lives. Prostate cancer is aggressive and tremendously invasive. Dogs who develop clinical signs have a guarded to poor prognosis.