Surgery

Complete Cystectomy

Complete removal of the urinary bladder is a drastic procedure with the potential for long term tumor control and the associated tumor pain control. The downside of this procedure is incontinence, possible scarring of the ureters, possible loss of kidney function, and possible blood chemical abnormalities. The kidneys normally deliver urine to the bladder for storage via ureters. After the bladder is removed, the ureters are attached to the colon so that the patient effectively passes urine rectally along with stool. Alternatively, the ureters can be attached to the vagina or another area. Special diets are required after surgery as well as long term antibiotics, frequent blood test monitoring, and free access to an area for urination or pet diapers will be needed (1).

This study from 2016, illustrates the results of a complete cystectomy on 4 dogs with TCC. Minor complications occurred in all dogs, including bleeding and edema of the ureterostomy site during the first 2–3 days after surgery. One dog developed urine scald that resolved with improved stoma care and hygiene. Median survival time after surgery was 279 days (range, 47–498). Distant metastases were documented in 2 of the 4 dogs at 47 days (bone) and 369 days (lung) after surgery (3).

Laser Ablation

Laser Ablation has been used for many years in humans with urinary tract cancer. A surgical laser is used to vaporize the tumor from the surface of the bladder and urethra (1). A study conducted in 2006, evaluated 8 dogs that underwent carbon dioxide (CO2) laser ablation of transitional cell carcinoma in the bladder trigone and proximal portion of the urethra and were also treated with mitotranxone and piroxicam. Median disease-free interval (i.e. the time without significant symptoms) was 200 days and median survival time was 299 days. Adverse treatment effects were observed in 2 dogs; signs included mild, self-limiting inappetance and lethargy. The procedure appeared to be well tolerated; all treated dogs had rapid resolution of clinical signs of disease of the lower portion of the urinary tract. These survival times were felt to be similar to those achieved with chemotherapy alone and no surgery at all; however, a more lasting resolution of symptoms was felt to have been achieved with this combination treatment (4).

Another study using Laser Ablation to treat dogs with TCC was conducted in 2012 using 38 dogs. The median survival time was 380 days, (range, 11 to 1,906 days). 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 (5). Dr. Knapp at Purdue, wrote a Letter to the Editor that published this 2012 study. Dr. Knapp discusses her concerns with this study, as it did not discuss other treatments these dogs were given before or after the Laser Ablation. These other treatments would have contributed to the median survival time. She also mentions the risks of Laser Ablation are high and Purdue prefers to use stents for urethral obstruction due to TCC (6).

Electrochemotherapy

Electrochemotherapy (ECT) combines the administration of chemotherapy drugs with the application of permeabilizing pulses having appropriate waveform in order to enhance the captation of antitumor molecules by tumor cells (9). The first and still most actively used chemotherapy agent in ECT has been bleomycin. This drug can enter the cell membrane only through specific protein receptors, resulting in slow and extremely limited uptake under normal conditions (9).

ECT has proven safe in treating soft tissue cancers in companion animals. It is now being studied to treat bladder cancer in dogs. A study from Brazil, posted in March 2023 and currently being peer-reviewed, has shown success in safely treating bladder cancer in 21 dogs. This study used electrochemotherapy (ECT) with intravenous bleomycin (BLM) as a selective local therapy. Complete response (CR) was achieved in 62% of the dogs (13/21), while partial response (PR) was achieved in 24% (5/21). The mean survival and disease-free survival times were 420 (range 7-1021 days) and 405 (range 30-981 days) days, respectively. An objective response rate (ORR) of 86% was achieved. 77% of the dogs achieving a complete response required only one session of ECT (10).

19 of the 21 dogs, had mild adverse effects during the postoperative period (VCOG grade 1). Two patients had more serious complications (VCOG grade 3), developing ureteral stenosis 69 and 73 days after the procedure. These dogs underwent a surgical procedure for the placement of a temporary ureteral stent which was removed after recovery. The two patients completely recovered their previous quality of life once the stents were placed (10).

Dr. Joseph A. Impellizeri in New York is one of the few veterinarians here in the United States with experience using electrochemotherapy to treat bladder cancer. 

Urinary Catheter

Wendy Brooks, DVM, describes “a permanently placed urinary catheter can be implanted in the patient’s urinary tract to create more comfortable urination. The placement of a foreign body in this way will predispose the patient to bladder infection and frequent screening cultures will be needed; still, in one study six out of seven owners reported satisfaction with results. Obviously, this procedure does nothing to hinder the tumor’s growth. Owners will need to empty the bladder with a drainage tube at least three times a day to avoid stagnation of urine. The entrance to the catheter must be kept clean and must be cleaned daily. Tube dislodgement is a serious complication. Newer tubes are short and a longer drainage tube is attached during bladder emptying. More traditional permanent catheters are longer and will require some sort of wrap or garment for protection. If a tube dislodges, it must be replaced by within 48 hours as scar tissue rapidly forms to close the opening into the bladder. Sedation is required for tube replacement; it is not something an owner can do at home (1)”.

Urethral Stents

A metal stent is placed in the urethra to allow urine passage through the tumor. This procedure is a similar concept as the permanent catheter but more high tech. The stent is placed either surgically or with a video radiography called fluoroscopy. The procedure is relatively simple and not invasive but does require specific equipment. Urinary incontinence is unfortunately a common problem after this procedure (affecting 39 percent of dogs that have it done) and special garments/diapers may be needed indoors. Female patients are more predisposed to incontinence issues following stenting (1).

In a study from 2017, 26 dogs with various causes of obstruction (not just TCC) received urethral stents due to obstruction via radiography instead of fluoroscopy. Median survival time was 5 months (range, 1–48 months). All dogs were discharged from the hospital with urine outflow restored. Intraprocedural complications included guide wire penetration of the urethral wall in 1 dog and improper stent placement in a second dog. Both complications were successfully managed at the time of the procedure with no follow‐up problems noted in either patient (7).

In a study published in 2012, specifically reviewing urethral stents in 17 dogs with TCC, the median survival time 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 (n=3), acute reobstruction shortly after the procedure (n=1), and stent migration (n=2). Of the 17 owners surveyed, 16 were satisfied with the outcome and would recommend urethral stent placement (8).