Transitional cell carcinoma

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Transurethral cystography of a transitional cell carcinoma in a dog[1]

Transitional cell carcinoma (TCC) are a relative common cancer of the urinary tract of dogs[2].

Transitional cell carcinoma accounts for 50% to 75% of reported cases of canine urinary bladder cancer[3] 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[4].

Most TCCs are located in the trigone of the bladder, although the ductus deferens[5], ureter or prostate epithelial tissue can also be involved[6].

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.

Clinically affected dogs are more often female dogs, with a predisposition reported in Scottish Terrier, Beagle, and Airedale Terrier breeds[7].

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[8].

Physical examination findings usually include urethral masses palpable by rectal or vaginal examination, palpable abdominal masses, prostatomegaly, distended bladders, or evidence of abdominal pain[9].

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)[10].

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[11].

In dogs, the prognosis is poor in most cases, unless a total cystectomy is performed.

References

  1. VSSO
  2. Vinall RL et al (2012) Expression of microRNAs in urinary bladder samples obtained from dogs with grossly normal bladders, inflammatory bladder disease, or transitional cell carcinoma. Am J Vet Res 73(10):1626-1633
  3. Lee JY et al (2007) Expression of cyclooxygenase-2, P-glycoprotein and multi-drug resistance-associated protein in canine transitional cell carcinoma. Res Vet Sci 83:210–216
  4. Henry CJ (2003) Management of transitional cell carcinoma. Vet Clin North Am Small Anim Pract 33:597–613
  5. Guerin VJ et al (2012) Transitional cell carcinoma involving the ductus deferens in a dog. J Am Vet Med Assoc 240(4):446-449
  6. Malek S et al (2011) Metastatic transitional cell carcinoma in proximal humerus of a dog. Can Vet J 52(9):1013-1017
  7. Mutsaers AJ et al (2003) Canine transitional cell carcinoma. J Vet Intern Med 17:136–144
  8. Grillo TP et al (2007) Hypertrophic osteopathy associated with renal pelvis transitional cell carcinoma in a dog. Can Vet J 48(7):745-747
  9. Norris AM et al(1992) Canine bladder and urethral tumors: A retrospective study of 115 cases (1980–1985). J Vet Intern Med 6:145–153
  10. Henry CJ (2003) Management of transitional cell carcinoma. Vet Clin Small Anim 33:597–613
  11. Cerf DJ & Lindquist EC (2012) Palliative ultrasound-guided endoscopic diode laser ablation of transitional cell carcinomas of the lower urinary tract in dogs. J Am Vet Med Assoc 240(1):51-60