prostatic TUMORS

BACKGROUND

Prostate tumors are rare in dogs and very rare in cats. There is no known association between neuter status and the development of prostatic tumors. The vast majority of prostatic tumors are malignant carcinomas and highly metastatic. Metastasis to the sublumbar lymph nodes, lungs, and bone is common.

DIAGNOSIS

Prostate tumors are diagnosed with urinalysis, blood tests, and imaging modalities such as contrast radiographs and ultrasound. A definitive diagnosis is possible with traumatic catheterization and urine sediment cytology. A cystoscope can also be used to collect biopsies, but this is not widely available. Transabdominal, perineal, perirectal, and ultrasound-guided aspirates have been described but are not recommended because of the risk of seeding tumor cells into the abdomen, subcutaneous tissue, and skin.

CLINICAL STAGING

An abdominal ultrasound is recommended to check for metastasis to the regional lymph nodes and liver. Chest radiographs or CT scans are done to check for metastasis to the lungs.

TREATMENT

There is no known effective treatment for prostatic tumors. Options for treatment of the local prostatic tumor include partial prostatectomy, total prostatectomy, and radiation therapy. Total prostatectomy provides excellent control of the local tumor but urinary incontinence is a common complication. Partial prostatectomy is a palliative procedure but decreases clinical signs caused by the tumor while minimizing the risk of urinary incontinence. Radiation therapy can be effective, but careful planning of the radiation field is required to minimize acute radiation effects to the intestines and urinary bladder.

Urethral stenting or placement of a cystostomy tube is occasionally required for dogs with obstruction of urine outflow because of the tumor.

Chemotherapy is recommended and involves the use of non-steroidal anti-inflammatory drugs (ie, meloxicam, deracoxib or piroxicam) and mitoxantrone.

PROGNOSIS

The prognosis is guarded to poor for dogs with prostatic carcinomas. The median survival time for dogs surviving > 7 days after diagnosis is only 30 days, but most of these dogs are not treated. Recent reports of palliative procedures (partial prostatectomy, urethral stenting, transurethral resection, and chemotherapy) show median survival times of up to 6.9 months.

To be updated