Outcome of urethral stent placement for management of urethral obstruction secondary to transitional cell carcinoma in dogs: 19 cases (2007–2010)

Sarah K. McMillan Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

Search for other papers by Sarah K. McMillan in
Current site
Google Scholar
PubMed
Close
 DVM
,
Deborah W. Knapp Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN 47907.

Search for other papers by Deborah W. Knapp in
Current site
Google Scholar
PubMed
Close
 DVM, MS, DACVIM
,
José A. Ramos-Vara Indiana Animal Disease Diagnostic Laboratory, Purdue University, West Lafayette, IN 47907.

Search for other papers by José A. Ramos-Vara in
Current site
Google Scholar
PubMed
Close
 DVM, PHD
,
Patty L. Bonney Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

Search for other papers by Patty L. Bonney in
Current site
Google Scholar
PubMed
Close
 BS
, and
Larry G. Adams Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

Search for other papers by Larry G. Adams in
Current site
Google Scholar
PubMed
Close
 DVM, PHD, DACVIM

Abstract

Objective—To determine the outcome in dogs undergoing urethral stent placement for management of urethral obstruction secondary to transitional cell carcinoma (TCC).

Design—Retrospective case series.

Animals—19 dogs with histopathologically confirmed TCC.

Procedures—Information regarding urethral stent placement and follow-up treatment was obtained from review of medical records. Quality of life assessment was performed with an owner questionnaire.

Results—Self-expanding nitinol stents were successfully placed in 17 of 19 dogs; stent placement was not possible in one dog, and another dog was euthanatized 2 days after stent placement, but before discharge from the hospital. Median survival time in 17 dogs following successful long-term stent placement was 78 days (range, 2 to 366 days). Complications following stent placement in 18 dogs included incontinence (n = 7), reobstruction from continued growth of urethral TCC (3), acute reobstruction shortly after the procedure (1), and stent migration (2). Of the 17 owners surveyed, 16 were satisfied with the outcome and would recommend urethral stent placement.

Conclusions and Clinical Relevance—The placement of self-expanding nitinol urethral stents was successful in alleviating TCC-induced urethral obstruction and providing good quality of life for most dogs.

Abstract

Objective—To determine the outcome in dogs undergoing urethral stent placement for management of urethral obstruction secondary to transitional cell carcinoma (TCC).

Design—Retrospective case series.

Animals—19 dogs with histopathologically confirmed TCC.

Procedures—Information regarding urethral stent placement and follow-up treatment was obtained from review of medical records. Quality of life assessment was performed with an owner questionnaire.

Results—Self-expanding nitinol stents were successfully placed in 17 of 19 dogs; stent placement was not possible in one dog, and another dog was euthanatized 2 days after stent placement, but before discharge from the hospital. Median survival time in 17 dogs following successful long-term stent placement was 78 days (range, 2 to 366 days). Complications following stent placement in 18 dogs included incontinence (n = 7), reobstruction from continued growth of urethral TCC (3), acute reobstruction shortly after the procedure (1), and stent migration (2). Of the 17 owners surveyed, 16 were satisfied with the outcome and would recommend urethral stent placement.

Conclusions and Clinical Relevance—The placement of self-expanding nitinol urethral stents was successful in alleviating TCC-induced urethral obstruction and providing good quality of life for most dogs.

Transitional cell carcinoma is the most common cancer of the canine urinary tract and represents approximately 1.5% to 2% of all cancers in dogs.1,2 Transitional cell carcinoma usually affects the trigone region of the bladder and proximal portion of the urethra. Because of the location, tumor growth can lead to stranguria, dysuria, or complete obstruction of urethra or ureters. Urinary obstruction is the cause of death in approximately 60% of dogs with TCC.1,3 Treatment options for the management of obstruction of the urethra include urethral stent placement, cystostomy tube placement, surgical diversion, and ultrasound-guided cystoscopic laser ablation. In many cases, owners elect euthanasia.2,4 The use of long-term cystostomy tubes is hampered by complications, which occur in up to 85% of dogs. These complications include inadvertent tube removal requiring replacement, recurring urinary tract infections, and urine leakage.5,6 Multiple surgical techniques have been described to manage urinary tract obstruction, including transurethral resection, ureterocolonic anastomosis, and resection of bladder neck and proximal portion of the urethra.7–9 However, these techniques are technically challenging and are associated with substantial complications, such as metabolic derangements, pyelonephritis, urethral perforation, and tumor seeding.7–9 A novel approach that uses ultrasound-guided cystoscopic laser ablation of urethral TCC has also been reported; however, this technique is also technically challenging, requires repeated procedures and lengthy hospital stays, and is associated with considerable cost.4

Stents have recently been evaluated for use in dogs with urethral obstruction resulting from a variety of urinary tract tumors. Protocols that use balloon-expandable and self-expanding stents have been successful in relieving obstruction.10 The purpose of the study reported here was to characterize the use of self-expanding nitinol stents in dogs with TCC to determine the effectiveness, potential complications, and long-term survival rate of and overall owner satisfaction with the procedure.

Materials and Methods

Case selection—Medical records of dogs evaluated at the Purdue University Veterinary Teaching Hospital for complete or partial urinary obstruction due to histopathologically confirmed TCC of the urinary tract from 2007 to 2010 were reviewed. Urethral stent placement was first performed at our institution in 2007. Dogs were selected for inclusion in this study if a self-expanding nitinol urethral stent was placed or urethral stent placement was attempted. Information collected from the medical records regarding the dogs included signalment, historical information regarding the dogs' clinical signs at the time of initial evaluation for obstruction, prior treatment for TCC, World Health Organization criteria tumor stage,11 and the date and cause of death. In regard to urethral stent placement, information extracted included degree of urethral obstruction prior to stent placement, presence of a urinary tract infection prior to stent placement, stent size, percentage of the urethral length stented in female dogs, complications, and medical treatments received after stent placement.

Urethral stent placement—All dogs were placed under general anesthesia for urethral stent placement. Dogs with postrenal azotemia and electrolyte abnormalities at the time of initial evaluation were stabilized prior to anesthesia by the placement of an indwelling urethral catheter and administration of IV fluid therapy. The anesthesia protocol varied on the basis of the needs of each individual dog. Dogs without a histologic diagnosis of TCC underwent cystoscopy prior to urethral stent placement. Uncovered self-expanding nitinol stentsa were placed via described techniques with adaptations.10

In 18 dogs, uncovered self-expanding nitinol stentsa were used, and in 1 dog, 2 self-expanding covered nitinol stents encapsulated with expanded polytetrafluoroethyleneb were placed. Briefly, a measuring catheterc was placed in the colon by inserting a flexible tipped urological guidewired,e through the measuring catheter. The measuring catheter was then advanced over the guide-wire though the rectum into the colon while feeding the measuring catheter over the guidewire. The colon catheter was positioned parallel to the area of suspected urethral obstruction. The hair around the prepuce or vulva was clipped, and the area was scrubbed with chlorhexidine. A flexible tipped urological guidewired,e was introduced into the urethra through an open-ended ureteral catheterf until the proximal end of the guidewire was coiled within the urinary bladder, which was observed with fluoroscopy. The open-ended ureteral catheter was withdrawn, leaving the guidewire in place, and an appropriately sized vascular sheath (7 to 10F) was placed over the guidewire. An iodinated contrast agent mixed with sterile saline (0.9% NaCl) solution (50:50) was infused into the bladder to achieve moderate bladder distension. A retrograde positive contrast urethrogram was performed with fluoroscopy for documentation of the urethral obstruction. In female dogs, the vascular access sheath was withdrawn through the urethra during retrograde infusion of iodinated contrast agent to attempt to obtain maximal urethra distension and determine length and width measurements of the urethra. The colonic measuring catheter, which has 10 radiopaque bands at 1-cm intervals, was visualized on the urethrogram next to the urethra to determine the length of obstruction caused by the tumor mass (Figure 1), the length of the urethra measured from trigone to papilla in female dogs, and the widest diameter of urethra adjacent to the obstruction. The width of the stent was selected to be at least 10% larger than the widest diameter of the urethra adjacent to the obstruction. When possible, the length of the stent was selected to allow 0.5 to 1 cm of the stent to be in contact with normal tissue proximal and distal to the obstruction. When the entire length of the urethra was diseased in female dogs, the length of the stent was chosen with the goal of stenting approximately 67% to ≤ 75% of the length of the urethra. After stent placement, the bladder was manually expressed to ensure urethral patency, and dogs were monitored in the hospital for at least 12 hours after stent placement to ensure the dog was able to void urine effectively.

Figure 1—
Figure 1—

Fluoroscopic image of urethral stent placement in a spayed female dog. Stent placement in this dog was unsuccessful as a result of proximal migration of the stent. Stent migration likely occurred because of inadequate contact of the proximal end of the stent with the proximal portion of the urethral wall (arrowhead) and from tumor compression leading to collapse of the distal aspect of the stent (black arrow), leading to proximal migration of the stent. Immediately upon deployment of the proximal end of the stent, the stent moved approximately 0.5 cm into the urinary bladder and, within 2 days, it migrated another 2 cm into the urinary bladder. Notice the measuring catheter in the colon (A) that is positioned adjacent to the urethra and has radiopaque bands at 1-cm intervals.

Citation: Journal of the American Veterinary Medical Association 241, 12; 10.2460/javma.241.12.1627

Quality of life questionnaire—To assess quality of life after urethral stent placement, an owner survey was conducted by telephone for all dogs discharged from the hospital. Owners were asked to quantitate the amount of stranguria and incontinence before and after stent placement. Owners were also asked whether they would recommend the procedure. Based on the owners' descriptions, dogs were graded on a scale from 1 to 4 for stranguria, where 1 = normal urination or mild straining during normal urination, 2 = moderate straining between normal urinations, 3 = severe straining with an inability to produce a normal urine stream, and 4 = complete urinary obstruction. Scores were also determined for level of incontinence before and after stent placement where levels of incontinence were defined as 1 = no incontinence, 2 = mild and occasional dribbling of urine between normal urinations, 3 = moderate incontinence with frequent episodes of involuntary urine discharge between normal urination, and 4 = incontinence with constant involuntary discharge of urine.

Results

Animals—Nineteen dogs met the inclusion criteria, including 14 spayed female and 5 neutered male dogs. The diagnosis of TCC was confirmed by review of the histopathologic findings by 1 pathologist (JRV). In male dogs, immnohistochemical staining for uroplakin III was performed because uroplakin III is most consistently associated with transitional epithelial origin of the cancer.12 Dog breeds included mixed (n = 6), Shetland Sheepdog (3), German Shorthaired Pointer (2), and 1 each of the following breeds: Scottish Terrier, Chihuahua, Collie, Basset Hound, Dalmatian, Golden Retriever, Miniature Schnauzer, and Miniature Pinscher. The median body weight of dogs at the time of stent placement was 25.9 kg (56.9 lb) with a range of 6 to 38.3 kg (13.2 to 84.3 lb). The median age at the time of stent placement was 10.9 years (range, 8.6 to 16.2 years). The tumor stage was classified at the time of the stent placement as T2N0M0 in 9 dogs, T3N0M0 in 7 dogs, T2N0M1 in 2 dogs, and T2N2M1 in 1 dog.

Clinical signs at initial evaluation for stent placement included stranguria (n = 15), dysuria (9), pollakiuria or urine leakage due to overflow incontinence (5), anorexia (2), vomiting (1), and uroabdomen (1). At the time of initial evaluation for urinary tract obstruction, 15 dogs had complete obstruction and 4 dogs had progressive, partial urethral obstruction. The median time from documentation of obstruction to stent placement was 4 days, with a range from 0 to 12 days. Bacteriologic culture of urine prior to stent placement was performed in 16 dogs. Urinary tract infection was identified in 8 of these dogs. The most commonly cultured organisms were Escherichia coli, Pseudomonas spp, and Enterococcus spp. Four of the 8 dogs with positive results on cultures had 2 bacterial species isolated.

Eleven dogs had received treatment for their TCC prior to undergoing stent placement. Of these dogs, the number of protocols received before stent placement ranged from 1 to 6. Prior treatments included piroxicam (n = 3), deracoxib (2), mitoxantrone and piroxicam (4), carboplatin (3), vinblastine (2), azacitidine (1), doxorubicin and meloxicam (1), a COX inhibitor combined with metronomic dosing of cyclophosphamide (2), metronomic dosing of chlorambucil and deracoxib (1), metronomic dosing of cyclophosphamide with chlorambucil and a COX inhibitor (2), and an investigational vinblastine conjugate (1).

Urethral stent placement—Of the 19 dogs, 18 dogs had 23 stents placed, and in 1 dog, stent placement was not possible. Stent sizes used were 7 × 20 mm (n = 1), 6 × 40 mm (1), 6 × 60 mm (3), 10 × 60 mm (1), 7 × 30 mm (1), 8 × 40 mm, (1), 8 × 60 mm (5), and 10 × 80 mm (3); the size was not recorded in the medical records for 7 stents. Urethral stent placement successfully relieved the urethral obstruction in 17 dogs. There were 2 dogs in which stent placement was considered unsuccessful. In the first dog, a guidewire could not be passed retrograde up the urethra because of extensive tumor infiltration. In this dog, cystocentesis was performed and the guidewire was passed through the needle and into the urethra in an attempt to pass the guidewire antegrade. Because of the severity of the tumor, passage of the guidewire was not possible, and this dog was euthanized under anesthesia without a stent being placed. In the second dog, an expanded polytetrafluoroethylene covered stentb was placed with the end of the stent in the distal third of the urethra in an area with extensive tumor involvement. The dog was unable to urinate after recovery from anesthesia. Tumor compression caused collapse of the distal aspect of the stent and also contributed to proximal migration of the stent (Figure 1). A second covered stent was placed in this dog, but the second stent also collapsed at the distal aspect and migrated proximally in the urethra. This dog was managed for 24 days with an indwelling urinary catheter, and then the owners elected to have the dog euthanized.

Outcomes—Seventeen dogs survived the immediate period after stent placement and were discharged from the hospital. One dog was euthanized during anesthesia when stent placement was not possible; a second dog was euthanized in the hospital 2 days after stent placement because of suspected chemotherapy-associated sepsis, which did not respond to medical treatment. All dogs that survived to hospital discharge went on to receive additional treatment after stent placement and were reevaluated at variable intervals with abdominal radiography (Figure 2) and ultrasonography to monitor response of the TCC to treatment. Four dogs received COX inhibitors alone (3 piroxicam and 1 meloxicam). Thirteen dogs received ≥ 1 additional chemotherapy protocols, including vinblastine (n = 4), mitoxantrone and a COX inhibitor (4), carboplatin and a COX inhibitor (3), metronomic administration of chlorambucil (3), metronomic administration of chlorambucil and firocoxib (3), metronomic administration of cyclophosphamide with piroxicam (1), and metronomic administration of cyclophosphamide and chlorambucil with a COX inhibitor (2).

Figure 2—
Figure 2—

Lateral radiographic view of the abdomen of a neutered male dog following successful urethral stent placement (black arrow). Air can be seen in the urinary bladder from previous catheterization for ultrasonographic evaluation of the urinary bladder (A). This image was obtained 19 days after urethral stent placement.

Citation: Journal of the American Veterinary Medical Association 241, 12; 10.2460/javma.241.12.1627

The median survival time for the 17 dogs that had successful stent placement was 78 days (range, 2 to 366 days). One dog was still alive and undergoing treatment at 366 days after stent placement. Overall median survival time from diagnosis to death in all 19 dogs was 153 days (range, 24 to 920 days). The causes of death in the 17 dogs discharged from the hospital after stent placement were reobstruction leading to euthanasia (n = 3), metastasis (4), sepsis (1), resistant infection (1), severe incontinence (1), inappetence and stranguria (1), or unrelated to cancer (3). Three dogs died at home, and the cause of death was unknown.

Postmortem examination was performed on 10 dogs. Necropsy confirmed TCC within the bladder or urethra of all dogs. Metastases were detected in the lung (n = 8), regional lymph nodes (2), skin (3), vertebrae (1), kidney (1), heart (1), and brain (1). In the dog in which a stent was unable to be passed extensive tumor growth, bilateral hydronephrosis, and hydroureter were found. One dog had evidence of myocardial degeneration and necrosis, which led to cardiac dysfunction. Another dog was found to have pyelitis and suppurative splenitis.

Complications—Complications observed following stent placement included incontinence, reobstruction, and stent migration into the urinary bladder. After stent placement, 7 dogs had incontinence. Of these dogs, 5 were spayed females and 2 were neutered males. Two of the female dogs had two-thirds of their urethra stented to relieve their obstruction. Two dogs received phenylpropanolamine for treatment of their incontinence without any improvement noted. One of the female dogs had collagen injections performed distal to the urethral stent, which temporarily improved the incontinence.

Three dogs had recurrent obstruction at 20, 47, and 95 days after initial stent placement due to continued tumor growth. Two dogs were assessed for the location of the reobstruction. In one dog, the tumor grew over the proximal opening of the stent, and in the other dog, the tumor occluded the distal aspect of the stent. The dog that had the proximal reobstruction had a second urethral stent placed to relieve the obstruction and was ultimately euthanized for an unrelated problem 205 days after placement of the second stent.

Stent migration into the urinary bladder occurred in 1 dog after initial successful stent placement. This dog was evaluated because of pollakiuria 80 days after the stent was initially placed. Abdominal radiography revealed that the stent was within the urinary bladder. In this dog, a cystotomy was performed to remove the migrated stent. The dog remained continent after surgery and did not need an additional stent, presumably because of 60% regression in the size of the urethral and trigonal tumor in response to chemotherapy.

One dog had both stent migration and acute reobstruction. In this dog, reobstruction was noted acutely 1 day after stent placement. In this dog, incomplete urethral distension during the initial positive contrast urethrogram resulted in an inaccurate measurement of the urethral diameter, and the stent that was placed was not wide enough to fully engage the urethral mucosa. Reobstruction occurred because the initial urethral stent was undersized, leading to proximal migration in the urethra. In the process of placing a urinary catheter to relieve urinary obstruction, the urethral stent was dislodged completely into the bladder. A second, wider urethral stent was successfully placed, and a cystotomy was performed to remove the initial undersized stent from the bladder. This dog never had any further reobstruction or stent migration events and died of metastatic disease 221 days after the second stent was placed.

Quality of life questionnaire—Of the 17 dogs that survived to discharge, 16 had follow-up obtained via the owner questionnaire and 1 dog was lost to follow-up. Median time between stent placement and follow-up surveys with owners was 480 days. The median stranguria score prior to stent placement was 4, which improved to a median score of 1 after stent placement. Seven owners reported a decrease in the frequency of urination. The median incontinence score after stent placement was 2, and 10 dogs had incontinence scores of ≤ 2. Fifteen of the 16 owners said they would recommend this procedure to other owners. The owner who did not recommend the procedure was satisfied with the dog's quality of life after the procedure but not the survival time after the procedure.

Discussion

The technique of urethral stent placement for palliation of any malignant urethral obstruction has been described in a report10 of the use of self-expanding stents in 10 dogs. The present study was performed to specifically determine the outcome for a larger number of dogs with TCC undergoing stent placement to relieve urethral obstruction and receiving continuing treatment for TCC with chemotherapy or COX inhibitors.

At the time of stent placement, 15 of 19 dogs had complete obstruction. Stent placement was successfully performed in 17 of 19 dogs. Stent sizes ranged from 7 × 20 mm up to 10 × 80 mm, with the most common stent size being an 8 × 60 mm. There were 2 dogs in which stent placement was unsuccessful. In one of these dogs, the urethra had been obstructed for 12 days prior to initial evaluation, and the tumor had narrowed the lumen too dramatically to allow passage of a urological guidewire for stent placement. The second dog had an intraluminal compressive tumor causing considerable collapse of the distal end of the stent and migration. This was the only dog in this study that received a covered stent. The ends of covered stents are uncovered and should allow for the tumor to engage the stent but would prevent the tumor from extending through the center openings in the stent wall and therefore may not allow the stent to imbed in the wall as securely as would occur with an uncovered stent. During stent placement, the proximal end of the stent moved from the proximal portion of the urethra into the trigone of the bladder and the stent ends did not properly engage the bladder wall (Figure 1), allowing for proximal stent migration over time. The stent could also have been undersized if the urethra was not fully distended during retrograde urethrogram measurements, which in combination with the covered nature of the stent, might have prevented the stent from engaging the wall of the urethra appropriately.

Stent placement prolonged life beyond the time that euthanasia would have likely been performed by a median time of 78 days for the 17 dogs that had successful stent placement. Of those dogs, 11 received a urethral stent at the time of histologic diagnosis. One of these dogs had received chemotherapy at another hospital, as determined on the basis of results of cytologic evaluation prior to stent placement. In this subset of 11 dogs, the median survival time was 155 days after stent placement. In the remaining 6 dogs, urethral obstruction occurred at a median time of 250.5 days after diagnosis, with most dogs having failed multiple chemotherapy protocols. The median survival time in this group of dogs was only 53 days after stent placement.

The median survival time of 78 days in this study appears longer than the reported 20-day median survival time.10 Two important differences likely account for this increased survival time. In the present study, 13 dogs went on to receive medical treatment, with some dogs receiving multiple different chemotherapy protocols, whereas in the previous study,10 all dogs received only a COX inhibitor. Additionally, in the previous study,10 the most common diagnosis was prostatic carcinoma, with only 3 dogs that had TCC. Prostatic carcinoma is generally considered to have a more guarded prognosis because of a high metastatic rate and resistance to treatment.2,13

The overall median survival time from diagnosis to death was 153 days, which appears to be shorter than in reports1,2 of dogs with TCC. The reason for this difference is unknown; however, previous reports have included all dogs with TCC, whereas the present study focused on dogs where TCC led to complete or partial urethral obstruction. Cases of obstructive lesions likely represent a more advanced stage of disease than in dogs with no obstructive masses. Only 3 of 18 dogs died of TCC-induced urethral obstruction. The lower overall median survival rate may be the result of the more aggressive biological behavior of urethral TCC, compared with TCC of the urinary bladder.3,g In this study, 10 of the 18 dogs that survived to discharge were known to have developed metastasis at the time of death.

Incontinence, stent migration, atonic bladder, and acute reobstruction have been described as possible complications after urethral stent placement.10 No cases of atonic bladder were observed in dogs of the present study. Incontinence, recurrent obstruction, and stent migration were noted to occur after stent placement in this group of dogs.

Incontinence occurred after stent placement in 7 of 18 dogs in the present study, with 5 of 14 female dogs and 2 of 4 male dogs developing incontinence. Four dogs had severe (grade 4) incontinence, and 3 had moderate (grade 3) incontinence. In studies,10,h 25% to 47.6% of female dogs and 37.5% to 75% of male dogs developed incontinence after stent placement. Findings in the present study concur with reports that incontinence appears to occur more commonly in male dogs receiving urethral stents.

Stent migration after initial successful placement occurred in 2 of 18 dogs in the present study. In 1 dog, the stent migration was acute and attributed to improper stent selection (too narrow width of stent). A second stent was placed successfully with no additional migration or obstruction events. This illustrates that proper selection of stent size is an important factor to avoid migration. Delayed stent migration in the second dog may have been the result of substantial urethral tumor regression following chemotherapy or caused by errors in stent selection and placement. Although the stent width was judged to be adequate, the proximal end of the stent was purposefully placed into the trigone because the initial obstruction was at the junction of the urinary bladder with the proximal portion of the urethra. Given the placement of the proximal end of stent into the urinary bladder, this prevented the proximal end of the stent from engaging the bladder mucosa on 1 side and may have contributed to stent migration. This stent also was the shortest stent placed in any dog in our study. This dog did not require a second stent and was able to urinate normally after cystotomy to remove the stent from the urinary bladder because of regression of the tumor that had originally obstructed the urethra. Proximal migration of a short urethral stent has been reported and was also attributed to tumor regression, proximal location of the stent, and inadequate engagement of the ends of the stent with the bladder mucosa.10

Of the 4 dogs with reobstruction in the present study, 1 dog had reobstruction soon after stent placement because of improper stent sizing and 3 dogs had reobstruction many weeks after stent placement. The 3 dogs with recurrent obstruction weeks after stent placement had tumor growth causing obstruction, with a mean time to urethral reobstruction of 54 days after initial stent placement. In the 2 dogs assessed for reobstruction location, tumor grew over either the proximal or distal opening of the stent but did not extend through the interstices of the stent.

Owner questionnaires revealed that owners were satisfied with their dogs' quality of life, and 16 of 17 owners would recommend the procedure to other owners. The 1 owner who did not recommend the procedure was unsatisfied with the duration of life her dog had after stent placement, rather than the quality of life. This owner's dog survived 41 days after stent placement and died unexpectedly at home. A necropsy was not performed to determine the cause of death. Quality of life surveys demonstrated that all dogs had reduction in stranguria after stent placement, and 7 of 17 dogs had a decrease in the frequency of urination. Many owners commented that understanding potential complications and the cost of the procedure was important to help them to decide whether to pursue urethral stent placement for their dog.

In conclusion, urethral stent placement is a valuable technique for management of dogs with TCC with urethral obstruction. Stent placement can extend a life with good quality for dogs with TCC. Dog owners should be informed of possible complications from this procedure, including incontinence, stent migration, and reobstruction due to continued tumor growth.

ABBREVIATIONS

COX

Cyclooxygenase

TCC

Transitional cell carcinoma

a.

Vet Stent-Urethra, Infiniti Medical, Malibu, Calif.

b.

Fluency Plus Treacheobroncial Stent Graft, Bard, Tempe, Ariz.

c.

Diagnostic Marker Catheter, Infiniti Medical, Malibu, Calif.

d.

0.035 inch × 150-cm, Sensor Dual-Flex wire, Boston Scientific, Natick, Mass.

e.

0.035 inch × 150-cm, Weasel wire, Infiniti Medical, Malibu, Calif.

f.

5F × 70-mm Open-Ended Ureteral Catheter, Cook Urological, Bloomington, Ind.

g.

Borgatti Jeffreys A, Greenberg CB, Lucroy MD, et al. Prognostic significance of urethral involvement of transitional cell carcinoma of the urinary bladder in dogs (abstr), in Proceedings. 25th Annu Conf Vet Cancer Soc 2005;22.

h.

Blackburn A, Berent A, Weisse C, et al. Urethral stenting in canine patients with urothelial carcinoma: a review of 41 cases (2004–2008) (abstr). J Vet Intern Med 2010;24:676.

References

  • 1. Mutsaers AJ, Widmer WR, Knapp DW. Canine transitional cell carcinoma. J Vet Intern Med 2003; 17:136144.

  • 2. Knapp DW. Tumors of the urinary system. In: Withrow SJ, Vail DM, eds. Small animal clinical oncology. 4th ed. St Louis: Saunders, 2007;649658.

    • Search Google Scholar
    • Export Citation
  • 3. Knapp DW, Glickman NW, DeNicola DB, et al. Naturally-occurring canine transitional cell carcinoma of the urinary bladder: a relevant model of human invasive bladder cancer. Urol Oncol 2000; 5:4759.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4. Cerf DJ, Lindquist EC. Palliative ultrasound-guided endoscopic diode laser ablation of transitional cell carcinomas of the lower urinary tract in dogs. J Am Vet Med Assoc 2012; 240:5160.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5. Stiffler KS, McCrackin Stevenson MA, Cornell KK, et al. Clinical use of low-profile cystostomy tubes in four dogs and a cat. J Am Vet Med Assoc 2003; 223:325329.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6. Beck AL, Grierson JM, Ogden DM, et al. Outcome of and complications associated with tube cystostomy in dogs and cats: 76 cases (1995–2006). J Am Vet Med Assoc 2007; 230:11841189.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 7. Saulnier-Troff FG, Busoni V, Hamaide A. A technique for resection of invasive tumors involving the trigone area of the bladder in dogs: preliminary results in two dogs. Vet Surg 2008; 37:427437.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 8. Stone EA, Withrow SJ, Page RL, et al. Ureterocolonic anastomosis in ten dogs with transitional cell carcinoma. Vet Surg 1988; 17:147153.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 9. Liptak JM, Brutscher SP, Monnet E, et al. Transurethral resection in the management of urethral and prostatic neoplasia in 6 dogs. Vet Surg 2004; 33:505516.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10. Weisse C, Berent A, Todd K, et al. Evaluation of palliative stenting for management of malignant urethral obstructions in dogs. J Am Vet Med Assoc 2006; 229:226234.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 11. Owens L. TNM classification of tumors in domestic animals. Geneva: World Health Organization, 1980;34.

  • 12. Ramos-Vara JA, Miller MA, Boucher M, et al. Immunohistochemical detection of uroplakin III, cytokeratin 7, and cytokeratin 20 in canine urothelial tumors. Vet Pathol 2003; 40:5562.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 13. Fan TM, LP de Lorimier. Tumors of the male reproductive system. In: Withrow SJ, Vail DM, eds. Small animal clinical oncology. 4th ed. St Louis: Saunders, 2007;637645.

    • Search Google Scholar
    • Export Citation
  • Figure 1—

    Fluoroscopic image of urethral stent placement in a spayed female dog. Stent placement in this dog was unsuccessful as a result of proximal migration of the stent. Stent migration likely occurred because of inadequate contact of the proximal end of the stent with the proximal portion of the urethral wall (arrowhead) and from tumor compression leading to collapse of the distal aspect of the stent (black arrow), leading to proximal migration of the stent. Immediately upon deployment of the proximal end of the stent, the stent moved approximately 0.5 cm into the urinary bladder and, within 2 days, it migrated another 2 cm into the urinary bladder. Notice the measuring catheter in the colon (A) that is positioned adjacent to the urethra and has radiopaque bands at 1-cm intervals.

  • Figure 2—

    Lateral radiographic view of the abdomen of a neutered male dog following successful urethral stent placement (black arrow). Air can be seen in the urinary bladder from previous catheterization for ultrasonographic evaluation of the urinary bladder (A). This image was obtained 19 days after urethral stent placement.

  • 1. Mutsaers AJ, Widmer WR, Knapp DW. Canine transitional cell carcinoma. J Vet Intern Med 2003; 17:136144.

  • 2. Knapp DW. Tumors of the urinary system. In: Withrow SJ, Vail DM, eds. Small animal clinical oncology. 4th ed. St Louis: Saunders, 2007;649658.

    • Search Google Scholar
    • Export Citation
  • 3. Knapp DW, Glickman NW, DeNicola DB, et al. Naturally-occurring canine transitional cell carcinoma of the urinary bladder: a relevant model of human invasive bladder cancer. Urol Oncol 2000; 5:4759.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4. Cerf DJ, Lindquist EC. Palliative ultrasound-guided endoscopic diode laser ablation of transitional cell carcinomas of the lower urinary tract in dogs. J Am Vet Med Assoc 2012; 240:5160.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5. Stiffler KS, McCrackin Stevenson MA, Cornell KK, et al. Clinical use of low-profile cystostomy tubes in four dogs and a cat. J Am Vet Med Assoc 2003; 223:325329.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6. Beck AL, Grierson JM, Ogden DM, et al. Outcome of and complications associated with tube cystostomy in dogs and cats: 76 cases (1995–2006). J Am Vet Med Assoc 2007; 230:11841189.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 7. Saulnier-Troff FG, Busoni V, Hamaide A. A technique for resection of invasive tumors involving the trigone area of the bladder in dogs: preliminary results in two dogs. Vet Surg 2008; 37:427437.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 8. Stone EA, Withrow SJ, Page RL, et al. Ureterocolonic anastomosis in ten dogs with transitional cell carcinoma. Vet Surg 1988; 17:147153.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 9. Liptak JM, Brutscher SP, Monnet E, et al. Transurethral resection in the management of urethral and prostatic neoplasia in 6 dogs. Vet Surg 2004; 33:505516.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10. Weisse C, Berent A, Todd K, et al. Evaluation of palliative stenting for management of malignant urethral obstructions in dogs. J Am Vet Med Assoc 2006; 229:226234.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 11. Owens L. TNM classification of tumors in domestic animals. Geneva: World Health Organization, 1980;34.

  • 12. Ramos-Vara JA, Miller MA, Boucher M, et al. Immunohistochemical detection of uroplakin III, cytokeratin 7, and cytokeratin 20 in canine urothelial tumors. Vet Pathol 2003; 40:5562.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 13. Fan TM, LP de Lorimier. Tumors of the male reproductive system. In: Withrow SJ, Vail DM, eds. Small animal clinical oncology. 4th ed. St Louis: Saunders, 2007;637645.

    • Search Google Scholar
    • Export Citation

Advertisement