Prostatic neoplasia in five dogs

Post-castration prostatic involution: A morphometric and endocrine study of healthy canines and those with benign prostatic hyperplasia

The objective of this study was to evaluate the effect of castration on dimensions of the prostate by B-mode ultrasound for 90 days, as well as to evaluate changes in serum concentrations of testosterone and oestradiol in clinically healthy canines and those with benign prostatic hyperplasia (BPH). Three groups of animals were used: healthy canines castrated on day 0 (HCC, n = 8), canines with a diagnosis of benign prostatic hyperplasia (BPHC, n = 9) castrated on day 0 and healthy uncastrated canines (IHCC, n = 10). Prostate size was obtained by B-mode ultrasound, while blood samples were collected (days 0, 7, 14, 28, 60 and 90 post-castration) to determine the serum testosterone and oestradiol concentration. Castration did not affect serum oestradiol concentrations. Castration led to a decrease in serum testosterone (reaching values <20 ng/dl in the first week, p < .05), causing a gradual decrease in dimensions of prostate parameters relative to body weight (p < .05). Canines with BPHC had similar prostate dimensions as the IHCC group 2 weeks post-castration. In relation to the prostate's relative parameters, the decrease with time was greater in canines with BPHC than those in the HCC group. When evaluating parameters as a percentage of relative change, the decrease with time was similar in both castrated groups, except for relative length percentage, which presented a more pronounced decline in BPHC canines than HCC canines. In conclusion, castration is an effective, fast and long-lasting treatment for canine patients with BPH, as it causes a rapid decrease in blood testosterone concentrations and a decrease in glandular volume, but does not affect serum oestradiol concentrations. This study did not determine the mechanisms of action, but allowed us to observe (based on morphometric variables) that characteristics of prostate involution after castration differed between canines with BPH and healthy canines.

Prostatic leiomyosarcoma in a dog treated using a multimodal approach

Prostatic leiomyosarcoma is an uncommon tumor encountered in male dogs, with only 2 cases reported in the veterinary literature with no follow-up described. A 12-year-old male intact German Wirehaired Pointer presented for evaluation of straining to defecate and urinate. Whole body computed tomography (CT) examination identified a spherical multicavitary expansile mass arising from the prostate gland and severely obliterating the pelvic canal. Partial subcapsular prostatectomy was performed, and histological and immunohistochemical results were consistent with prostatic leiomyosarcoma. Metronomic cyclophosphamide and nonsteroidal anti-inflammatory drugs were administered as adjuvant chemotherapy. Follow-up CT 10 months later indicated no signs of recurrence or metastasis. To the best of our knowledge, this patient represents the first report of successful multidisciplinary treatment consisting of partial subcapsular prostatectomy and adjuvant chemotherapy for prostatic leiomyosarcoma in a dog. After 15 months of follow-up, the patient remained recurrence-free without metastasis.

Lower urinary tract cancer

Lower urinary tract neoplasia is uncommon in dogs and cats, though transitional cell carcinoma (TCC) is the most common tumor of the lower urinary tract in both species. Clinical signs are not specific for neoplasia, but neoplasia should be considered in patients that are older, have specific risk factors, or have persistent, severe, or relapsing signs. Local disease is often the cause of death or euthanasia; local control is challenging owing to tumor size and location. Systemic therapy is the mainstay of treatment. Prognosis is generally guarded, but therapy can result in improvement in clinical signs and quality of life.

Canine prostate carcinomas express markers of urothelial and prostatic differentiation

Prostate carcinoma and transitional cell carcinoma (TCC) occur in the prostate gland of older dogs and have morphologic similarities when evaluated by light microscopy. The dog is a commonly used animal model for studying human prostate carcinoma; therefore, it is important to accurately differentiate canine prostate carcinomas from TCCs. We investigated whether keratin 7 (K7) and arginine esterase (AE) would aid differentiation of canine prostate carcinoma from TCC. K7 expression was evaluated in normal and neoplastic canine prostate and bladder tissues using immunohistochemistry. The expression of AE messenger ribonucleic acid (mRNA) in normal and neoplastic canine prostate and bladder was detected using northern blots and reverse transcriptase-polymerase chain reaction (RT-PCR). In addition, AE enzyme activity was measured in normal and neoplastic canine prostate and bladder tissues. We found marked similarities in K7 expression in prostate carcinomas and TCCs. AE mRNA was present in high levels in normal prostatic tissue but was reduced in prostate carcinoma by northern blot assay. Nested RT-PCR detected AE mRNA both in TCCs (13 of 15) and in prostate carcinomas (13 of 13). Enzymatic activity of AE was high in normal prostate gland and in some prostate carcinomas, whereas normal bladder and TCCs produced lower levels of AE. In conclusion, K7 and AE cannot be used to differentiate TCC from prostate carcinoma in dogs.