Transurethral Resection in the Management of Urethral and Prostatic Neoplasia in 6 Dogs

Evaluation of urethral thickness using ultrasonography in healthy small-breed dogs

Introduction

Urethral thickness measurements can be indicative of the pathological state of a patient; however to the best of our knowledge, no measurement reference range has been established in small-breed dogs. This study aimed to establish reference ranges for total urethral thickness and urethral wall thickness in healthy small-breed dogs; "urethral wall thickness" was assumed to be 1/2 of the "total urethral thickness."

Methods

Total urethral thickness was measured by ultrasonography in 240 healthy small-breed dogs. In both female and male dogs, the thickness was measured in the mid-sagittal plane. In female dogs, it was measured immediately before the pelvic bone. In male dogs, it was measured caudal to the prostate and cranial to the pelvic bone. The total urethral thickness we measured is the total thickness of the collapsed urethra, which is the sum of the thicknesses of the dorsal and ventral urethral wall.

Results

The mean value of total urethral thickness was 3.15 ± 0.83 mm (urethral wall thickness, 1.58 ± 0.41 mm) in 240 small-breed dogs. The total urethral thickness was significantly greater in male dogs than in female dogs (p < 0.001), even when compared among the same breeds (p < 0.05). The mean value of the total urethral thickness in females was 2.78 ± 0.60 mm (urethral wall thickness, 1.39 ± 0.30 mm), and 3.53 ± 0.86 mm (urethral wall thickness, 1.76 ± 0.43 mm) in males. There was very weak positive correlation between body weight (BW) and total urethral thickness (R2 = 0.109; β = 0.330; p < 0.001). Intraobserver reliability measured by intraclass correlation coefficient (ICC) was 0.986 (p < 0.001) and interobserver reliability measured by ICC was 0.966 (p < 0.001).

Discussion

This study described the differences in total urethral thickness between breeds, sexes, and sterilization status, and the correlation between BW and total urethral thickness. Furthermore, this is the first study to provide reference ranges of total urethral thickness and urethral wall thickness in small-breed dogs using ultrasonography, and is expected to be useful for urethral evaluation in veterinary diagnostic imaging.

Description of the technique for laparoscopic radical prostatectomy in canine cadavers: 2D vs. 3D camera

OBJECTIVE

To describe the technique of laparoscopic radical prostatectomy in canine cadavers.

STUDY DESIGN

Cadaveric study.

ANIMALS

8 canine cadavers.

METHODS

Specimens were randomly divided into a 2D or 3D group. The vesicourethral anastomosis (VUA) was performed with 5 mm laparoscopic needle holders. A unidirectional barbed suture was used to complete the VUA with two simple continuous suture patterns. The number of stitches placed, the patency of the anastomosis, and the distance between the VUA and the ureters were recorded.

RESULTS

Four dogs were entered into each group. The prostatectomy was completed in each dog following the same technique. VUA were completed with nine stitches (range: 8-10 stitches) for the 2D group and ten stitches (range: 9-11 stitches) for the 3D group (p<0.176). All the stitches were placed full thickness. The VUA was patent in each case. The left ureter was 1.05 cm (range: 0.5 to 1.1cm) from the VUA in the 2D group and 1.8 cm (range: 1.3-1.8 cm) for the 3D group (p< 0.025). The right ureter was 1.5 cm (range: 1 to 2 cm) from the VUA in the 2D group and 1.75 cm (range: 1.3-2 cm) for the 3D group (p< 0.55).

CONCLUSION

Laparoscopic radical prostatectomy can be performed with a 2D or a 3D camera in canine cadavers. The 3D camera results in more accurate placement of the sutures since they were placed further away from the left ureter.

CLINICAL SIGNIFICANCE

Radical prostatectomy with laparoscopy should be considered for dogs.

Comparison of leakage pressures of vesicourethral anastomosis performed with intracorporeal suturing in a simulator and conventional suturing ex vivo in canine cadaveric tissue

OBJECTIVE

To compare conventional and intracorporeal vesicourethral anastomosis (VUA) in canine cadaveric tissue.

STUDY DESIGN

Cadaveric ex vivo study.

STUDY POPULATION

Twenty-eight canine bladders with urethra.

METHODS

Specimens after prostatectomy were randomly divided into intracorporeal (I) group or conventional (C) group. For the I group, VUA was performed in a simulator with laparoscopic needle holders and telescope. For the C group, the anastomosis was performed in vitro with standard instruments. The VUA was performed with 4-0 monofilament absorbable suture and was completed with two simple continuous sutures. Surgical time, leakage pressure, site of leakage, and number of suture bites were recorded.

RESULTS

Fourteen samples were entered in each group. The dorsal side of the anastomosis was initially performed, followed by the ventral side. The median suturing time was 30.8 minutes (range, 19.3-39.2) for the I group and 17.3 minutes (range, 9.2-21.3) for the C group (P < .0001). The median leakage pressure was 10.9 mm Hg (range, 4.1-29.7) for the I group and 10.8 mm Hg (range, 6.2-18.5) for the C group (P = .94). The median number of stitches was 20 (range, 14-26) for the I group and 19 (range, 11-28) for the C group (P = .96). The distribution of the site of leakage was similar between groups (P = .381).

CONCLUSION

Vesicourethral anastomosis can be performed with leakage pressures similar to intracorporeal and conventional suturing.

CLINICAL SIGNIFICANCE

This study represents the first step toward laparoscopic radical prostatectomy in dogs.

Molecular Markers in Urinary Bladder Cancer: Applications for Diagnosis, Prognosis and Therapy

Cancer of the urinary bladder is a neoplasm with considerable importance in veterinary medicine, given its high incidence in several domestic animal species and its life-threatening character. Bladder cancer in companion animals shows a complex and still poorly understood biopathology, and this lack of knowledge has limited therapeutic progress over the years. Even so, important advances concerning the identification of tumour markers with clinical applications at the diagnosis, prognosis and therapeutic levels have recently been made, for example, the identification of pathological BRAF mutations. Those advances are now facilitating the introduction of targeted therapies. The present review will address such advances, focusing on small animal oncology and providing the reader with an update on this field. When appropriate, comparisons will be drawn with bladder cancer in human patients, as well as with experimental models of the disease.

Comparison of outcomes between medical and surgical treatment in dogs with prostatic adenocarcinoma: a retrospective study

Background

Prostatic cancer is uncommon in dogs. Dogs with prostatic carcinoma have been reported to have a poor prognosis. Information regarding prognosis with various surgery options as well as prognosis with surgical vs. medical treatment is lacking. This retrospective study compares the outcomes of medical management to surgical treatment in dogs with prostatic adenocarcinoma and assesses the surgical outcomes of patients who underwent total prostatectomy (TP) and prostatocystectomy (TPC). The medical records of 41 dogs with prostatic adenocarcinoma, between February 2008 and June 2019, were reviewed for information on signalment, clinical signs in the initial evaluation, preoperative diagnostic imaging findings, treatment type (non-surgical or surgical), surgery type, postoperative complications, adjunctive medical therapy, and survival time. The dogs were divided into non-surgical (n = 12) or surgical (n = 29) groups. The surgical group was subdivided into the TP (n = 20) and TPC (n = 9) subgroups.

Results

Age was not significantly different between the surgical (median 13.1 years [8.4–15.4] years) and the non-surgical groups (median 10.8 [7.7–15.3] years). Body weight (BW) was also not significantly different between the surgical (median 6.8 kg [2.4–34.5 kg]) and non-surgical groups (median 6.4 kg [3.7–9.12 kg]). The overall median survival time (MST) from the initial evaluation was significantly longer in the surgical than in the non-surgical group (337 vs. 90.5 days). The postoperative MST was significantly longer in the TP group than in the TPC subgroup (510 vs. 83 days). As TPC was performed in cases of tumor progression, its postoperative complications were severe, resulting in a shorter MST. Ten (50%) and 6 patients (30%) in the TP subgroup postoperatively showed mild and severe urinary incontinence, respectively, whereas all patients in TPC subgroup did show severe incontinence.

Conclusion

Results of the study suggest that surgical treatment of prostatic carcinoma results in longer survival times over medical management alone. In particular, TP might be recommended for improving survival time and quality of life in canine prostatic adenocarcinoma that does not infiltrate the bladder. Early detection is key for a survival advantage with surgical treatment.

Novel surgical approach to neoplastic lesions in the distal part of the urethra: A pilot cadaver study comparing open and hybrid techniques

Tumours of the distal urethra in female dogs are often difficult to treat, and the surgical methods described thus far have technical limitations. This study aimed to present a novel approach to the surgical treatment of distal urethral tumours. This study used dog cadavers to evaluate the technical feasibility of surgically removing neoplastic lesions in the distal urethra and compared surgical outcomes of open surgery with those of hybrid surgery (combination of laparoscopy and open surgery). Open intact, open spayed, hybrid intact, and hybrid spayed dog cadaver groups underwent surgery (n = 6 per group). The novel surgical method was based on vulvovaginectomy (ovariohysterectomy in intact dogs), resection of the distal part of the urethra, and pre-pubic urethrostomy. Outcomes of interest included technical feasibility of each procedure, using both surgical techniques, wound length, time required to complete the procedure, and the incidence of intraoperative ureter and rectum injuries. Surgical technique and reproductive status affected operating time. Technique choice affected wound length; the surgical wound was longer in the open group than in the hybrid group. Macroscopic evaluation of the rectum did not reveal any damage to the wall. There was no evidence of ureter leakage or obstruction in any case. The present findings suggest that both open and hybrid surgery can be used to treat distal urethral tumours.

Case report laparoscopy-assisted pre-pubic urethrostomy as a palliative procedure for resection of distal urethral tumor in a female dog

Background

This paper presents the first described case of laparoscopy-assisted prepubic urethrostomy and laparoscopic resection of a tumor of the distal part of the urethra in a female dog as a palliative treatment.

Case presentation

An intact, 11 -year-old, mixed breed female dog, weighing 15 kg, was admitted with signs of urinary obstruction and difficulty with catheterization. Vaginal, rectal, and endoscopic examinations revealed a firm mass in the pelvic cavity at the level of the pelvic urethra. Ultrasound and computed tomography examination showed enlargement of the urethral wall (5.5 cm width and 3 cm thick), which was significantly restricting the patency of the urethra. The lesion affected only the distal part of the urethra without the presence of local or distant metastatic changes.

The affected portion of the urethra was laparoscopically removed while performing pre-pubic urethrostomy with laparoscopy. The patient regained full consciousness immediately after the end of anesthesia, without signs of urinary incontinence. Histopathological examination of the removed urethra revealed an oncological margin only from the side of the bladder. In the period of 2.5 months after the procedure, the owner did not notice any symptoms that could indicate a postoperative recurrence, which was diagnosed three months after the procedure.

Conclusions

Pre-pubic urethrostomy can be successfully performed with the assistance of laparoscopy. The use of minimally invasive surgery will allow, in selected cases, removal of the urethral tumor, and in inoperable cases, to perform a minimally invasive palliative pre-pubic urethrostomy.

Laparoscopic-assisted cutaneous ureterostomy in a canine patient with prostatic carcinoma

A 9‐year‐old neutered male Dachshund dog was assessed for stranguria. An enlarged prostate was identified on physical examination, and a diagnosis of prostatic carcinoma confirmed by cytology. Due to a neoplastic lower urinary tract obstruction, palliative surgical urinary diversion treatment was performed with laparoscopic assisted cutaneous ureterostomy (LACU). The dog recovered well without any major complications. Adjuvant chemotherapy was maintained and continued for post‐surgical medical therapy. This report describes a novel minimally invasive assisted technique in canine patients for palliative treatment of prostatic neoplasia.

Investigation of the use of microwave ablation with and without cooling urethral perfusion for thermal ablation of the prostate gland in canine cadavers

OBJECTIVE

To investigate the use of microwave ablation (MWA) with cooling urethral perfusion and with no perfusion (MWA-UP and MWA-NP, respectively) for prostate gland ablation in canine cadavers.

ANIMALS

Cadavers of 18 sexually intact male dogs.

PROCEDURES

After technique refinement in 2 cadavers, laparotomy with ultrasound-guided MWA-UP (n = 8) or MWA-NP (8) of the prostate gland was performed in 16 cadavers. Normograde cystourethroscopy was performed before and after treatment; recorded images were reviewed in a blinded manner for scoring of urethral mucosal discoloration and loss of integrity. Difficulty with cystoscope insertion was recorded if present. Excised prostate glands were fixed for serial sectioning, gross measurements, and calculation of percentage ablation. Percentages of prostate tissue necrosis from MWA, denuded urethral mucosa, and depth of epithelial surface loss in an adjacent section of the colon were estimated histologically. Variables of interest were statistically analyzed.

RESULTS

Difficulty with cystoscope insertion after treatment was significantly more common and scores for urethral mucosal discoloration and loss of integrity were significantly higher (indicating more severe lesions) for the MWA-NP group than for the MWA-UP group. The histologically assessed percentage of denuded urethral mucosa was also greater for the MWA-NP group. Overall median percentage prostate gland ablation was 73%; this result was not associated with prostate gland volume or chronological order of treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

MWA-UP induced subtotal thermal necrosis of prostate glands in canine cadavers while limiting urethral mucosal injury. Further study is required to optimize the technique and evaluate its safety and efficacy in vivo as a future curative-intent treatment for prostatic tumors in dogs.

Cutaneous seeding of transitional cell carcinoma of the urinary bladder after placement of a subcutaneous ureteral bypass device in a dog with bilateral ureteral obstruction

CASE DESCRIPTION

A 12-year-old spayed female Jack Russell Terrier was presented with pollakiuria and stranguria.

CLINICAL FINDINGS

Transitional cell carcinoma (TCC) of the urinary bladder trigone and urethra was diagnosed via CT, cystoscopic, and histologic examinations. Azotemia developed 2 weeks following diagnosis, secondary to bilateral ureteral obstruction.

TREATMENT AND OUTCOME

Percutaneous antegrade ureteral stenting was unsuccessful; therefore, a subcutaneous ureteral bypass (SUB) device with 2 nephrostomy and 1 cystostomy catheters was surgically placed. Two months following placement of the SUB device, the dog developed a firm, multilobulated cutaneous mass at the site of the subcutaneous access port of the SUB device. Results of cytologic examination of cells aspirated from the mass were consistent with TCC. Within 1 month of confirmation of TCC of the cutaneous mass, the mass was ulcerated and infected, and the dog was euthanized because of signs of pain and perceived poor quality of life.

CLINICAL RELEVANCE

Seeding of neoplastic cells is a known complication of needle aspiration or biopsy or surgery in people and dogs with carcinomas. The occurrence of TCC at the SUB port site suggested caution with the placement of a SUB device in dogs with obstructive TCC.

A combined protocol with piroxicam, chemotherapy, and whole pelvic irradiation with simultaneous boost volumetric modulated arc radiotherapy for muscle-invasive canine urinary transitional cell carcinoma: First clinical experience

The aims of this pilot study were to evaluate the feasibility and efficacy of high-dose hypofractionated volumetric modulated arc radiotherapy (VMAT) applied to whole pelvic region radiotherapy (WPRT) with multilevel simultaneous integrated boost (MLSIB) combined with piroxicam and chemotherapy for the treatment of canine transitional cell carcinoma (TCC) of the lower urinary tract with muscle invasion TCC. Twelve dogs were enrolled, according to stage, in two groups: group 1, TCC confined to the urinary tract; group 2, TCC with metastasis. The planning target volume dose was tailored from 36 to 42 Gy in 6 fractions. All dogs were prescribed piroxicam and radiosensitizing carboplatin, and six received chemotherapy after radiotherapy. Serial follow-ups with computed tomography and magnetic resonance imaging were performed. Disease control and toxicity effects were evaluated according to the Response Evaluation Criteria in Solid Tumors and Veterinary Radiation Therapy Oncology Group criteria. The treatment was well tolerated, and no high-grade side effects were reported. The median overall survival times for groups 1 and 2 were 1,230 and 150 days, respectively. A considerable percentage of patients in group1 (50%) were still alive at the time of writing this paper, and a longer follow-up could enable a more accurate survival analysis. This preliminary analysis shows that VMAT applied to the WPRT with MLSIB is an effective and safe option for dogs with lower urinary TCC, although the presence of metastases worsens the prognosis.

Prostatectomy as a treatment for canine prostate cancer: a literature review

Canine prostate cancer is a relatively rare condition that accounts for less than 1% of all cancers diagnosed in dogs (Obradovich et al., 1987; Bryan et al., 2007). Out of 431 dogs with prostatic conditions diagnosed in a Dutch center, 56 suffered from prostatic carcinoma (Teske et al., 2002). Several forms have been identified, of which adenocarcinoma (AC), transitional cell carcinoma (TCC), and undifferentiated cell carcinoma are the most common (Bennett et al., 2018; Cunto et al., 2019).

Lower Urinary Tract Neoplasia

Lower urinary tract neoplasia in companion animals is a debilitating and often life-threatening disease. Tumors of the bladder, urethra, and prostate often occur independently, although extension of these tumors into adjacent regions of the lower urinary tract is documented frequently. The most common lower urinary tract tumor in dogs and cats is transitional cell carcinoma (TCC). In both dogs and cats, TCC affecting the urinary bladder is generally considered to be highly aggressive with both local and metastatic disease potential, and this disease poses unique treatment challenges. Whereas much literature exists regarding the TCC disease process, treatment options, and prognosis in dogs, relatively few studies on feline TCC have been published due to the lower incidence of TCC in this species. Prostate tumors, most commonly adenocarcinomas, occur less commonly in dogs and cats but serve an important role as a comparative model for prostate neoplasia in humans. This article serves as a review of the current information regarding canine and feline lower urinary tract neoplasia as well as the relevance of these diseases with respect to their human counterparts.

A pilot study of toceranib/vinblastine therapy for canine transitional cell carcinoma

Background

Effective therapies for transitional cell carcinoma (TCC) are limited, with objective response rates to most chemotherapeutic regimens below 20%. The purpose of this study was to investigate the biologic activity of combined toceranib phosphate and vinblastine chemotherapy for treatment of TCC. A secondary objective was to compare the utility of Computed Tomography (CT) and abdominal ultrasound (AUS) in tumor response assessments.

Results

Dogs with TCC received vinblastine at 1.6 mg/m2 every 2 weeks and toceranib at 2.5–2.75 mg/kg on Monday/Wednesday/Friday. Tumor monitoring was achieved through CT and AUS. Five patients completed the 16-week study. Based on AUS assessments, 3 dogs experienced biologic response to therapy including partial responses (PR, n = 2) and stable disease (SD, n = 1). Based on CT, 5 dogs experienced a biologic response (n = 2 PR, n = 3 SD). Both imaging modalities (ultrasound and CT) were found to provide repeatable measurements between operators, however agreement between operator measurements was greater when CT images were used to assess tumor size.

Conclusions

The combination of toceranib and vinblastine did not result in improved response rates. While agreement in tumor volume assessments between both AUS and CT were excellent between operators, this did not extend to assessment of tumor response. The higher rate of concordance between operators when assessing response to treatment with CT suggests that CT should be considered for future clinical trials involving canine bladder TCC to improve the accuracy and repeatability of tumor measurement. The data suggest that response to therapy as assessed by AUS or CT do not predict duration of clinical response.

TOLERABILITY AND TUMOR RESPONSE OF A NOVEL LOW-DOSE PALLIATIVE RADIATION THERAPY PROTOCOL IN DOGS WITH TRANSITIONAL CELL CARCINOMA OF THE BLADDER AND URETHRA

Previously reported radiation protocols for transitional cell carcinoma of the canine lower urinary tract have been ineffective or associated with increased side effects. Objectives of this retrospective, cross-sectional study were to describe safety of and tumor responses for a novel palliative radiation protocol for transitional cell carcinoma in dogs. Included dogs had cytologically or histologically confirmed transitional cell carcinoma of the bladder or urethra, and were treated with 10 once-daily fractions (Monday-Friday) of 2.7 Gy. Thirteen dogs were sampled, with six treated using radiation as first-line (induction) therapy and seven treated using radiation as rescue therapy after failing previous chemotherapy. Within 6 weeks of radiation, 7.6% (1/13) dogs had a complete response, 53.8% (7/13) partial response, 38.5% (5/13) stable disease, and none had progressive disease. Three patients presenting with urethral obstruction had spontaneous micturition restored during the treatment protocol. A single patient with unilateral ureteral obstruction was patent at recheck examination. Median survival time from time of initial diagnosis was 179 days. Median survival time from start of radiation was 150 days. Acute radiation side effects occurred in 31% (4/13) patients and were classified as grade 1 or 2. No significant late side radiation side effects were reported. No variables examined were identified as prognostic factors. Findings indicated that the reported radiation protocol was safe in this sample of dogs with bladder and urethral transitional cell carcinoma. Future prospective studies are needed to determine utility of this treatment as a rescue therapy in patients with complete urinary tract obstruction.

Interventional urology: endourology in small animal veterinary medicine

The use of novel image-guided techniques in veterinary medicine has become more widespread, especially in urologic diseases. With the common incidence of urinary tract obstructions, stones disease, renal disease, and urothelial malignancies, combined with the recognized invasiveness and morbidity associated with traditional surgical techniques, the use of minimally invasive alternatives using interventional radiology and interventional endoscopy techniques has become incredibly appealing to owners and clinicians. This article provides a brief overview of some of the most common procedures done in endourology in veterinary medicine to date, providing as much evidence-based medicine as possible when comparing with traditional surgical alternatives.

Management of transitional cell carcinoma of the urinary bladder in dogs: a review

Transitional cell carcinoma (TCC), also referred to as urothelial carcinoma, is the most common form of urinary bladder cancer in dogs, affecting tens of thousands of dogs worldwide each year. Canine TCC is usually a high grade invasive cancer. Problems associated with TCC include urinary tract obstruction, distant metastases in >50% of affected dogs, and clinical signs that are troubling both to the dogs and to their owners. Risk factors for TCC include exposure to older types of flea control products and lawn chemicals, obesity, female sex, and a very strong breed-associated risk. This knowledge is allowing pet owners to take steps to reduce the risk of TCC in their dog. The diagnosis of TCC is made by histopathology of tissue biopsies obtained by cystoscopy, surgery, or catheter. Percutaneous aspirates and biopsies should be avoided due to the risk of tumor seeding. TCC is most commonly located in the trigone region of the bladder precluding complete surgical resection. Medical treatment is the mainstay for TCC therapy in dogs. Although TCC is not usually curable in dogs, multiple drugs have activity against it. Approximately 75% of dogs respond favorably to TCC treatment and can enjoy several months to a year or more of good quality life. Many promising new therapies for TCC are emerging and with the close similarity between TCC in dogs and high grade invasive bladder cancer in humans, new treatment strategies found to be successful in canine studies are expected to help dogs and to be subsequently translated to humans.

Vinorelbine rescue therapy for dogs with primary urinary bladder carcinoma

The goal of this study was to evaluate the anti-tumour activity and toxicoses of vinorelbine as a palliative rescue therapy for dogs with primary urinary bladder carcinoma. Thirteen dogs refractory to prior chemotherapeutics and one dog naïve to chemotherapeutic treatment were enrolled. Vinorelbine (15 mg m(-2) IV) was administered intravenously along with concurrent oral anti-inflammatory drugs, if tolerated. A median of six doses of vinorelbine (range: 1-16) was administered. Two dogs (14%) had partial responses, and eight (57%) experienced stable disease. Subjective improvement in clinical signs was noted in 11 dogs (78%). Adverse events were mild and primarily haematological in nature. Median time to progression was 93 days (range: 20-239 days). Median survival time for all dogs was 187 days; median survival for 13 pre-treated dogs was 207 days. Vinorelbine may have utility in the management of canine primary urinary bladder carcinoma and should be evaluated in a prospective study.

Retrospective evaluation of doxorubicin-piroxicam combination for the treatment of transitional cell carcinoma in dogs

OBJECTIVES

To determine whether doxorubicin-piroxicam combination is safe and has activity against transitional cell carcinoma in dogs.

METHODS

Data was collected retrospectively from 34 dogs from two institutions over a 6-year period. Signalment, clinical presentation, treatment specifics, adverse events, response, progression-free survival and overall survival time were evaluated.

RESULTS

Dogs received doxorubicin every 3 weeks and daily piroxicam; 17 dogs (50%) had surgery. Clinical presentations were those typically reported for transitional cell carcinoma. Mean number of doses administered was 3·5. Of the 23 dogs with measurable disease, 14 (60·5%) had stable disease, 7 (30·5%) had progressive disease and 2 (9%) a partial response. Adverse events were generally manageable, and gastrointestinal in origin; one dog died of treatment-related complications. Overall median progression-free survival and overall survival were 103 and 168 days, respectively. Cytoreductive surgery did not result in prolongation of progression-free survival, but significantly prolonged overall survival. All dogs but one died as a result of disease progression.

CLINICAL SIGNIFICANCE

Doxorubicin-piroxicam combination therapy is well-tolerated in dogs with transitional cell carcinoma although progression-free survival, overall survival and biological response rates appear modest. Combination with surgery appears to offer a survival advantage; however, this may reflect tumour location and volume. Prospective studies are necessary to compare activity of combination doxorubicin-piroxicam to currently applied therapies.

Metastasis of a Prostatic Carcinoma along an Omental Graft in a Dog

An 11-year-old male American Bulldog was presented for hematuria and tenesmus. It had been treated for chronic bacterial prostatitis with abscessation two years earlier and underwent castration and a prostatic omentalization procedure. There was no histologic evidence of prostatic neoplasia at that time. On physical examination, an enlarged prostate was found by rectal palpation, and it was characterized with ultrasonography and computed tomography. Surgical biopsies were obtained, and histopathology identified prostatic adenocarcinoma. It received carprofen and mitoxantrone chemotherapy in addition to palliative radiation therapy; it was euthanized six weeks later due to a progression of clinical signs. Necropsy findings included marked localized expansion of the prostatic tumor and dissemination of prostatic carcinoma cells throughout the peritoneal cavity along the omental graft with infiltration onto the serosal surfaces of most abdominal viscera and fat. This case represents a previously unreported potential complication of the omentalization procedure wherein carcinoma cells from a prostatic tumor that independently arose after omentalization may have metastasized along the surgically created omental graft.

Palliative ultrasound-guided endoscopic diode laser ablation of transitional cell carcinomas of the lower urinary tract in dogs

OBJECTIVE

To describe the development of ultrasound-guided endoscopic diode laser ablation for palliative management of urinary tract obstruction due to transitional cell carcinoma (TCC).

DESIGN

Prospective case series. Animals-38 dogs with urinary tract obstruction or potential obstruction caused by TCC.

PROCEDURES

Diagnosis of TCC of the urinary bladder and urethra was made by means of transabdominal ultrasonography and transurethral endoscopic biopsy. Transurethral endoscopic near-infrared diode laser ablation was performed to debulk and remove obstructive and potentially obstructive TCC lesions. Transabdominal ultrasonography permitted proper alignment of the endoscope and laser fiber for monitoring laser fiber penetration and subsequent tissue alteration or ablation. The primary outcome measured was median survival time.

RESULTS

Median survival time for all dogs was 380 days, with a range of 11 to 1,906 days. There was no significant difference in survival time between dogs that had TCCs with urethral involvement versus dogs that had TCCs without urethral involvement. Complications were stranguria, hematuria, stenosis at the cystourethral junction, spread of TCC within the lower urinary tract, spread to the urethrostomy site, urethral perforation, and bacterial cystitis.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that ultrasound-guided endoscopic diode laser ablation holds promise as a palliative treatment for dogs with TCC of the urinary tract. Ultrasonographic guidance and monitoring during laser irradiation was a useful addition to endoscopically applied transurethral diode laser ablation.

Urethral stenting in a cat with refractory obstructive feline lower urinary tract disease

A 10-year-old male Korean domestic short-haired cat was presented with refractory lower urinary tract obstruction. The cat was treated by urethral stent placement using a self-expanding nitinol intraluminal stent (Zilver 535 biliary stents, COOK, U.S.A.) subsequent with balloon expansion. Although the cat showed 2 days of transient hematuria after the stent placement, no further obstruction was occurred after the stent placement. Follow-up studies performed at monthly intervals have found no re-stenosis or particular complications, to date.

Preliminary results of intraoperative photodynamic therapy with 5-aminolevulinic acid in dogs with prostate carcinoma

Six client-owned dogs with prostate carcinoma were treated with a combination of (1) partial subcapsular prostatectomy using an Nd:YAG laser, (2) intraoperative photodynamic therapy using a halogen broad band lamp after local administration of a photosensitiser, and (3) systemic treatment with meloxicam. Median survival time was 41days (range 10-68days), which compared negatively with previous reports of subtotal laser prostatectomy combined with topical interleukin-2 administration, and photodynamic therapy alone. Despite treatment, the disease progressed locally, causing signs of stranguria to recur, and in the form of distant metastases. The recurrence of clinical signs due to the primary tumour despite photodynamic therapy is probably largely explained by insufficient penetration of light into the tissue. Better results may be obtained using other light sources (e.g. laser) and alternative techniques of light delivery, such as fibres or catheters allowing interstitial diffusion of light.

Evaluation of palliative stenting for management of malignant urethral obstructions in dogs

OBJECTIVE

To evaluate use of balloon-expandable and self-expanding metallic stents in management of malignant urethral obstructions in dogs.

DESIGN

Original study.

ANIMALS

12 dogs with malignant urethral obstructions.

PROCEDURES

The extent and location of urethral obstructions and the diameter of adjacent unaffected luminal segments were determined by use of fluoroscopically guided wires and measuring catheters. Stents were chosen to extend approximately 1 cm proximal and distal to the obstruction. Stent diameters were chosen to be approximately 10% greater than the diameter of healthy portions of the urethra to prevent displacement. Stents were placed in the urethra under fluoroscopic guidance to restore luminal patency.

RESULTS

3 dogs received balloon-expandable metallic stents, and 9 dogs received self-expanding metallic stents. The placement procedures were rapid, safe, and effective at restoring luminal patency and were not associated with major complications. Complications included recurrent urethral obstruction secondary to blood clot formation and urethral edema in 1 dog and stent dislodgement into the urinary bladder in 1 dog. All dogs were able to urinate immediately after the procedure. Nine dogs (3/4 females and 6/8 males) were continent or mildly incontinent after stent placement. Of the remaining 3 dogs, 2 developed severe incontinence and 1 had an atonic bladder. Seven dogs were considered to have good to excellent outcome, 3 had fair outcome, and 2 had poor outcome.

CONCLUSIONS AND CLINICAL RELEVANCE

Transurethral placement of metallic stents was a safe and effective palliative treatment option for dogs with malignant urethral obstructions.

Partial Prostatectomy Using Nd:YAG Laser for Management of Canine Prostate Carcinoma

OBJECTIVE

To report a technique for partial prostatectomy by laser dissection and to evaluate outcome and complications in dogs with prostate carcinoma (PCA).

STUDY DESIGN

Experimental and clinical case series.

ANIMALS

Four normal dogs and 8 dogs with PCA.

METHODS

Subcapsular partial prostatectomy, sparing the urethra and the dorsal aspect of the prostatic capsule, using Nd:YAG laser dissection to remove the prostatic parenchyma and control hemorrhage was performed in 4 normal dogs and subsequently in 8 dogs with histologically confirmed PCA. Additional treatment of PCA dogs included local application of interleukin-2 and systemic administration of meloxicam. Prostate size, complications, and survival time were recorded. Laser-associated thermal damage to surrounding tissue was evaluated by histology.

RESULTS

In normal dogs, no damage to the dorsal prostatic capsule or urethra was detected. In PCA dogs, median survival was 103 days (range, 5-239 days). Three dogs died from complications within 16 days, whereas 5 (median survival, 183 days; range, 91-239 days) had improvement or resolution of clinical signs. Urinary incontinence did not occur.

CONCLUSION

Laser assisted subcapsular partial prostatectomy can be performed in dogs with PCA without development of postoperative incontinence.

CLINICAL RELEVANCE

Subcapsular partial prostatectomy is a potential palliative treatment for PCA in dogs and may lead to the resolution of clinical signs for several months.