Transitional cell carcinoma
Transitional cell carcinoma accounts for 50% to 75% of reported cases of canine urinary bladder cancer and may also occur within the renal pelvis as a primary renal neoplasia or within the ureter as a primary ureteral transitional cell carcinoma.
The etiology of TCC is not completely understood, and is likely multifactorial, but a number of risk factors have been associated with this condition including obesity, diet and environmental pollutants.
Tumor grading is performed to ascertain metastatic index and therapeutic response.
- grade 1 is well differentiated
- grade 2 moderately differentiated (most common)
- grade 3 is anaplastic
Metastasis correlates with the depth of bladder wall invasion (i.e., clinical stage) and the tumor can spread into adjacent fat or regional organs, implantation into the peritoneal cavity, or lymphatic and hematogenous spread to other organs.
Symptoms include dysuria, hematuria, pollakiuria and stranguria, with a vaginal discharge in female dogs. Urinary obstruction, incontinence and lameness due to skeletal metastases or hypertrophic osteopathy are not uncommon.
Physical examination findings usually include urethral masses palpable by rectal or vaginal examination, palpable abdominal masses, prostatomegaly, distended bladders, or evidence of abdominal pain.
Diagnosis is based on urinalysis, radiographic and ultrasonographic imaging studies, ultrasound-guided needle biopsy of the urinary bladder or exploratory cystotomy.
Ultrasonography is recommended to determine the location and extent of bladder involvement, regional lymph node size and appearance, and involvement of adjacent anatomical structures such as the colon. Ultrasonography is superior to excretory urography and double-contrast cystography in detecting TCCs.
Treatment options available for canine TCC include surgical intervention, radiation therapy, chemotherapy (e.g. vinblastine), and non-steroidal anti-inflammatory drug therapy (for example, piroxicam or meloxicam).
Surgical treatment usually involves surgical intervention, with palliative tube cystostomy and/or partial or total cystectomy with urinary diversion combined with chemotherapy.
Ultrasound guided laser ablation has also been performed in dogs.
In dogs, the prognosis is poor in most cases, unless a total cystectomy is performed.
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