An update on diagnosing and treating urinary bladder transitional cell carcinoma in dogs - Veterinary Medicine
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An update on diagnosing and treating urinary bladder transitional cell carcinoma in dogs
These tumors in dogs are difficult to completely resect, so the prognosis for long-term survival is guarded. But new avenues of treatment are being discovered, and treatment protocols already in place can extend and enhance dogs' lives.


VETERINARY MEDICINE


Contrast cystography or abdominal ultrasonography


Figure 1. An ultrasonogram of a mass in the trigonal area and a distended ureter resulting from partial ureteral obstruction in a 9-year-old male castrated Shetland sheepdog with transitional cell carcinoma.
Bladder masses can be detected by contrast cystography or abdominal ultrasonography. Ultrasonography is more commonly used because it provides better visualization of the mass when proper equipment is used by an experienced ultrasonographer. To enhance visualization and localization of any masses (Figure 1), make sure the bladder is well-distended with urine or infused with saline solution.

Another advantage of ultrasonography is improved visualization of other abdominal structures. This includes better evaluation of the kidneys and ureters for possible complications and the assessment of potential metastatic sites, including the lymph nodes, liver, and spleen.


Figure 2. A photomicrograph of a cytocentrifuged urine sample obtained by traumatic catheterization in a 10-year-old male castrated Scottish terrier showing sheets and clusters of round to polygonal cells with a moderate amount of basophilic cytoplasm. The nuclei are round with a stippled chromatin pattern and prominent, multiple nucleoli. Note the moderate anisocytosis and anisokaryosis (Wright's stain, 400X). (Photo courtesy of Dr. Anne Barger, DACVP.)
Additionally, ultrasound guidance can help you select an appropriate biopsy site for transurethral traumatic catheterization, improving the diagnostic yield. While this diagnostic procedure has a relatively high yield for biopsy samples, the samples are usually small, occasionally making histologic interpretation difficult.21 Samples obtained with transurethral traumatic catheterization can also be submitted for cytologic analysis and are often highly cellular and of good diagnostic quality when quickly processed and fixed on glass slides, leading to a presumptive diagnosis (Figure 2). Nevertheless, histologic examination of tissue biopsy samples remains the only definitive method of confirming urinary bladder transitional cell carcinoma.

CLINICAL STAGING

Once a diagnosis of transitional cell carcinoma has been confirmed, the patient should be clinically staged. Like most solid tumors, transitional cell carcinoma can metastasize to numerous sites, and suspect findings should be evaluated to obtain prognostic information before you pursue therapy (Table 1).3


Table 1 TNM Staging of Canine Bladder Transitional Cell Carcinoma*
Appropriate imaging includes three-view thoracic radiography and abdominal ultrasonography to evaluate for distant or regional metastatic disease, respectively. Reported metastatic rates in dogs with histologically confirmed transitional cell carcinoma are 20% to 37%, with regional (iliac) lymph nodes and lungs being the most common sites.1,3


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