Transitional Cell Carcinoma of the Urinary Tract

Transitional Cell Carcinoma of the Urinary Tract – An Overview

  • The urinary tract consists of the kidneys, the ureters (the tubes running from the kidneys to the bladder), the urinary bladder (that collects urine and stores it until the pet urinates), and the urethra (the tube from the bladder to the outside, through which urine flows out of the body)
  • Transitional cell carcinoma is a cancer arising from the transitional epithelium within the kidney, ureters, urinary bladder, urethra, prostate, or vagina; the transitional epithelium is a specialized type of lining in the urinary tract that contracts or stretches in response to the size of the bladder and other organs

Signalment/Description of Pet

Breed Predilections

  • Scottish terriers, West Highland white terriers, Shetland sheepdogs, American Eskimo dogs, and dachshunds; may occur in any breed

Mean Age and Range

  • Dogs—8 years; range, 1–15+ years of age
  • Middle-aged to old, spayed, female small-breed dogs most commonly reported

Predominant Sex

  • Female

Signs/Observed Changes in Pet

  • Similar to those of bacterial urinary tract infection or the presence of stones in the urinary tract (known as “urolithiasis”); for pets showing temporary or no response to appropriate antibiotics, consider transitional cell carcinomaRecurrent straining with slow, painful discharge of urine (known as “stranguria”); abnormal frequent passage of urine (known as “pollakiuria”); blood in the urine (known as “hematuria”); difficulty urinating (known as “dysuria”); inability to control urination or leaking urine (known as “urinary incontinence”); or any combination of these signs
  • Physical examination findings often normal
  • Mass—occasionally may be felt in the abdomen at the location of the urinary bladder
  • Urethral or vaginal transitional cell carcinoma—may be able to feel mass during rectal examination
  • Rarely enlarged intrapelvic or sublumbar lymph nodes—may be able to feel during rectal examination

Causes and Risk Factors

  • Scottish terrier; obesity; environmental carcinogens (substances that cause cancer); long-term (chronic) exposure to certain flea-control products (such as organophosphates or carbamates); and rarely, long-term treatment or a large bolus dose of cyclophosphamide (a chemotherapeutic drug)

Treatment

Health Care

  • Outpatient—stable pets; initial workup generally takes 1–2 days, so hospitalization may be more convenient
  • Seek advice from a veterinary oncologist prior to initiating treatment and consider current recommendations
  • Radiation therapy

Activity

  • Normal

Diet

  • Normal, unless pet also has kidney failure

Surgery

Appendicular Sites (Relating to the Limbs)

  • Surgery for transitional cell carcinoma can be challenging as the tumor easily sheds cancer cells; these cells can be spread into the abdomen during surgery
  • Surgery may result in a cure, if the mass can be removed completely
  • Wide surgical excision (that is, surgically removing the tumor and wide borders of apparently normal tissue) is necessary; up to 50% of the urinary bladder may be removed surgically with minimal loss of function
  • Placement of a catheter from the bladder and exiting through the abdominal wall to allow urine to be removed from the body (procedure known as “tube cystostomy”)—may greatly prolong survival times by bypassing blockage of the urethra (known as “urethral obstruction”)
  • Urethral stenting (placing a medical “tube” inside the urethra) may prolong survival by temporarily relieving blockage of the urethra, and thereby, allowing the pet to urinate

Medications

Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive

  • Chemotherapy—piroxicam (Feldene), cisplatin (dogs), mitoxantrone (as single agents or as combination therapy for certain drugs); piroxicam and cisplatin cannot be combined because of kidney toxicity; other agents (doxorubicin or doxorubicin/cyclophosphamide combination) may have activity
  • Antibiotics—administered as necessary for secondary urinary tract infections

Follow-Up Care

Patient Monitoring

  • X-rays (radiographs) using contrast media in the bladder (known as “contrast cystography”) or ultrasound examination—every 6–8 weeks; assess response to treatment and screen for spread of cancer into the lymph nodes (known as “lymph-node metastases”)
  • Chest x-rays(radiographs)—every 2–3 months; detect spread of cancer into the lungs (known as “pulmonary metastatic disease”)

Possible Complications

  • Blockage of the urethra (the tube from the bladder to the outside, through which urine flows out of the body) or ureters (the tubes running from the kidneys to the bladder), and kidney failure
  • Spread of cancer (metastasis) to regional lymph nodes, lungs, or bone
  • Recurrent urinary tract infection
  • Lack of control of urination or urine leakage (urinary incontinence)
  • Reduction of bone-marrow activity (known as “myelosuppression”), resulting in low number of red blood cells, white blood cells, and/or platelets or gastrointestinal toxicity secondary to chemotherapy
  • Gastrointestinal ulceration secondary to piroxicam therapy

Expected Course and Prognosis

  • Long-term prognosis grave
  • Progressive disease probable
  • Median survival—no treatment, 4–6 months; with treatment, 6–12 months

Key Points

  • Long-term prognosis is poor, but control of signs to make the pet more comfortable (known as “palliation”) is often attainable
  • The tumor usually cannot be removed surgically in dogs

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