Prostatic Neoplasia in Dogs: Clinical Presentation, Diagnosis and Current Treatment Options

Although prostatic neoplasia is relatively uncommon in dogs, it remains one of the most challenging prostatic disorders encountered in clinical practice. A major concern is that affected dogs often present only after local invasion or metastasis has already occurred, limiting therapeutic options and contributing to a guarded prognosis. Maintaining clinical suspicion in middle-aged and older male dogs presenting with lower urinary tract signs, weight loss, or hindlimb weakness is therefore essential. A systematic diagnostic approach can help differentiate prostatic neoplasia from other prostatic disorders and guide appropriate case management. 

Clinical Profile of Prostatic Neoplasia 

Prostatic neoplasia accounts for approximately 5–7% of canine prostatic diseases, with the average age at diagnosis being around 10 years¹. The condition is seen more frequently in middle-aged and older dogs, while occurrence in younger animals is uncommon². 

The two most frequently diagnosed tumour types are prostatic adenocarcinoma and transitional cell carcinoma involving the prostatic urethra. Adenocarcinomas are most commonly diagnosed in dogs between 8 and 10 years of age³. 

Unlike benign prostatic disorders, prostatic neoplasia has not been shown to be prevented by castration. In fact, prostatic neoplasia has been observed with an equivalent or even higher frequency in castrated dogs compared with intact males³. Therefore, clinicians should not exclude prostatic neoplasia solely on the basis of neuter status. 

Recognizing the Clinical Signs 

The clinical presentation varies depending on the degree of local invasion and the presence of metastatic disease. Unfortunately, many dogs remain undiagnosed until the disease has progressed beyond the prostate. 

Common clinical findings include: 

• Hematuria 

• Stranguria 

• Tenesmus 

• Anorexia 

• Weight loss 

• Weakness of the hindlimbs 

Pain and neurological deficits affecting the pelvic limbs are frequently associated with metastasis to the pelvic bones and regional lymph nodes². 

Because these clinical signs may overlap with other prostatic disorders, careful evaluation is necessary to establish an accurate diagnosis. 

Diagnostic Approach 

Diagnosis begins with a thorough clinical examination. During transrectal palpation, the prostate is generally located within the pelvic canal, although advanced enlargement may cause it to shift into the abdomen. Importantly, detection of a palpable prostate during rectal examination in a castrated male dog should prompt further investigation to rule out prostatic neoplasia⁴. 

Ultrasonography provides valuable information regarding the architecture of the gland. Prostatic tumours typically appear as one or more hyperechoic lesions within an asymmetrically enlarged prostate with irregular margins¹. 

Radiographic evaluation may reveal: 

• Prostatic mineralization 

• Prostatomegaly 

• Regional lymphadenopathy 

• Pulmonary metastasis 

• Skeletal metastasis 

Confirmation of the diagnosis requires prostatic biopsy, which can be obtained under ultrasonographic or digital guidance. Histologically, five grades of adenocarcinoma have been described, with poorly differentiated tumours reported more commonly in castrated dogs⁴. 

Treatment Considerations 

Managing prostatic neoplasia remains challenging because most dogs are diagnosed at an advanced stage of disease. As a result, treatment options are often limited, and no therapy has consistently demonstrated a significant improvement in survival time⁴. 

Radiation therapy has been used to reduce prostatic size, although logistical limitations and the lack of demonstrated survival benefit restrict its routine application. In carefully selected dogs without evidence of metastasis, total prostatectomy may offer a potentially curative surgical option. However, microscopic metastatic disease is frequently present even when overt metastasis is not identified during surgery. 

Clinicians should also be aware that postoperative urinary incontinence is a well-recognized complication following total prostatectomy¹. Consequently, treatment decisions should consider disease extent, anticipated quality of life, and expected surgical outcomes. 

Practical Clinical Insights 

• Maintain suspicion for prostatic neoplasia in middle-aged and older dogs presenting with persistent lower urinary tract signs, unexplained weight loss, or hindlimb weakness. 

• A palpable prostate in a castrated male dog warrants further diagnostic evaluation, as castration does not eliminate the risk of prostatic neoplasia. 

• Ultrasonography and radiography complement each other by assessing both the primary lesion and potential metastatic spread. 

• Histopathological examination remains essential for confirming the diagnosis and characterizing the tumour. 

• Since many dogs are diagnosed after disease progression, early recognition and comprehensive staging are important for discussing realistic treatment options and prognosis with owners. 

References 

1. Verma A, Singh R, Jawre S, Khan A, Namdev N, Vishvakarma S, Sinha A. Prostate disorders in dogs, with a focus on benign prostatic hyperplasia (BPH): An overview. International Journal of Veterinary Sciences and Animal Husbandry. 2024;9(1):868-75. https://www.researchgate.net/profile/Asad-Khan-160/publication/383217672 

2. Teske ER, Naan EC, Van Dijk EM, Van Garderen E, Schalken JA. Canine prostate carcinoma: epidemiological evidence of an increased risk in castrated dogs. Molecular and cellular endocrinology. 2002 Nov 29;197(1-2):251-5. https://www.academia.edu/download/54503930/s0303-7207_2802_2900261-720170922-23092-pfhpo3.pdf 

3. Bryan JN, Keeler MR, Henry CJ, Bryan ME, Hahn AW, Caldwell CW. A population study of neutering status as a risk factor for canine prostate cancer. The prostate. 2007 Aug 1;67(11):1174-81. https://www.academia.edu/download/46695934/A_population_study_of_neutering_status_a20160621-31181-bgmuni.pdf 

4. Smith J. Canine prostatic disease: a review of anatomy, pathology, diagnosis, and treatment. Theriogenology. 2008 Aug 1;70(3):375-83. https://doi.org/10.1016/j.theriogenology.2008.04.039