Urinary Tract Tumors (Objectives Only)

List common locations for urothelial carcinomas to arise in the dog.

- Often located in the trigone of the bladder (Makes local intervention difficult because of urethral openings and ureter connections)

- Can also involve urethra and prostate

Identify at risk canine breeds for developing urothelial carcinomas.

- Scottish Terrier (#1)

- Eskimo Terrier

- Shetland Sheepdog

- West Highland White Terrier

- Keeshond

- Samoyed

- Beagle

- Dalmation

List common risk factors for the development of urothelial carcinomas in dogs.

- Breed

- Exposure to older generation flea control and lawn chemicals

- Obesity (mimics chronic inflamm., carcinogens hang out in adipocytes)

- Cyclophosphamide exposure

- Female (Marks mark/urinate more)

- Neutering (can contribute to obesity)

What diagnostics may be helpful in making a Dx of urothelial carcinoma?

- Overall health assessment (CBC/Chemistry, UA, Urine culture - free catch or catheter - Don't seed tumor cells with cysto; Evaluate UA for cells suggestive of neoplasia)

- Histopathology (Cystotomy, cystoscopy or traumatic/diagnostic catheterization, IHC with uroplakin III and GATA-3)

- Bladder Tumor Antigen Test (BTA): Older test, poor specificity, can be positive in patients with UTI, 90% sensitivity

- BRAF (Mutation present in urine samples from >80 % of all iUC cases; Can detect as few as 10 mutation bearing cells up to 4 months before clinical signs)

- CADET-BRAF)PLUS - detects DNA copy number changes to identify > 2/3 of iUC cases not identified by CADET BRAF; Done when BRAF/CADET BRAF is negative

Why is surgery uncommonly used for management of urothelial carcinoma?

- Rarely curative

- Not possible in most cases due to location and even with clean margins

- It can recur due to "field effect" (Malignant transformation of entire urothelium)

When is surgical management of urothelial carcinoma indicated?

- Obtain tissue for definitive diagnosis

- Eradicate lesions amenable to wide excision (distant from trigone)

- Relieve urinary tract obstruction

What are risks of surgery for urothelial carcinoma?

- Procedural risk

- Recurrence

- Seeding

What are surgical options for management of urothelial carcinoma?

- Total cystectomy + urinary diversion strategies (Serious complications)

- Prepubic cystostomy catheter (palliative)

- Stents (Palliative; Urethra and ureters can be stented in case of obstruction)

- Laser ablation (Obstructive relief) with CO2 or near-infared diode laser

What are complications of a prepubic cystotomy catheter?

- Urine leakage

- Tumor seeding

- Infection

- Displacement

- Damage

What are complications of stents?

- Incontinence (25-39%)

- Stent fracture

- Migration

- Tumor progression

What are complications of laser ablation?

- Perforation

- Transient postprocedural worsening of stranguira/hematuria

- Urethral stenosis and infection

True or false: iUC considered moderately radioresistant

- True; Use higher doses and less fractionation

What are options for radiation management of iUC?

- Intensity-Modulated and Image-Guided RT (IMRT/IGRT) with mild/self-limiting acute side effects and 10% late side effects

- Low dose palliative RT with mild acute side effects and no late side effects

What is the mainstay of treatment for iUC? What is the goal of this therapy?

- Systemic therapy is mainstay of treatment, either with NSAID, chemotherapy, or combination of the two

- Not curative; Goal is stable disease to partial remission; Rare to get complete remission

Why is essential to remeasure iUC masses every 8-12 weeks?

- Clinical signs do not necessarily reflect changes in tumor size

What is the prognosis for iUC?

- iUC growth can be controlled in ~75-80% of dogs, QOL is usually very good and MSTs have extended well beyond a year

What chemotherapeutic agent is often chosen first for iUC?

- Vinblastine

What are some supportive/palliative care options for iUC?

- NSAID/Pain management

- Catheterization to help relieve blockage and reduce risk of hydronephrosis

- Avmaquin- sulforaphane producing product (Found in cruciferous vegetables)

- Manage concurrent UTIs

Describe the metastatic rate for iUC?

- On presentation: 14-16%

- At euthanasia/necropsy: 42-58%

What are common metastatic sites for iUC?

- Regional LN

- Lungs

- Others: Liver, bone, kidney, adrenal gland, skin, heart, brain, and GIT

What is the CR rate, PFI, and MST for dogs with iUC treated with piroxicam alone?

- 3% CR

- 120 days - 4 months

- 244 days - 8 months

What is the CR rate, PFI, and MST for dogs with iUC treated with piroxicam and cisplatin?

- 14% CR

- 124 days

- 246 days

(higher CR than piroxicam alone but similar MST)