Bladder Cancer in Dogs: Symptoms and Treatment

When you notice your dog straining to urinate or see bloody urine, it’s easy to assume they have a simple urinary tract infection (UTI). While UTIs are common in dogs, these same clinical signs can indicate a rare but dangerous condition: bladder cancer. Both require veterinary attention, so don’t delay if your dog is having bathroom struggles!

If you’re facing a diagnosis of bladder cancer in your dog, we’re here to help you understand more about this condition and what you can expect.

Dog Bladder Cancer: Prevalence and Stages

When we say “bladder cancer in dogs,” we are typically referring to a specific cancer called transitional cell carcinoma (TCC), also known as urothelial carcinoma. TCC is a malignant cancer of the cells that line the bladder and part of the urethra, which carries urine from the bladder to the outside of the body. These cells are known as transitional epithelial cells. 

The tumor usually develops in the neck of the bladder, near where the ureters (tubes that move urine from kidneys to bladder) and urethra connect to the bladder, making surgery nearly impossible in most cases. In over half of canine patients, the urethra is also affected.

TCC is by far the most common type of bladder cancer in dogs, comprising 70-80 percent of cases. Other less common causes of bladder cancer in dogs include rhabdomyosarcoma and leiomyosarcoma. Leiomyosarcoma (malignant) and leiomyomas (benign) are approximately 12 percent of primary bladder tumors. Rhabdomyosarcomas (malignant) are very rare, but suspicion would be increased if the bladder tumor was noted in a young dog.

Overall, bladder cancer in dogs is uncommon, making up less than 2 percent of cancer cases. Most often, we see TCC in middle-aged to older, small breed dogs like Scottish Terriers, West Highland White Terriers, Beagles, and Shetland Sheepdogs. Specifically, Scottish Terriers are 18-20 times more likely to develop TCC than other breeds. The average age at diagnosis is 11 years old.

While veterinarians don’t typically assign specific stages to bladder cancer in dogs, this tumor is invasive and has the potential to spread to other areas of the body, such as the lymph nodes, lungs, and bone. For this reason, you may hear the veterinarian refer to “staging” the cancer, which means they want to investigate the extent of cancer spread. 

Causes of Dog Bladder Cancer in Dogs

Oftentimes, no cause is determined for bladder cancer. Because specific breeds, especially Scottish Terriers, are prone to TCC, genetics are an important factor. 

Female dogs get TCC more often than males. Current thinking is that females, who are less likely to urine mark, store their urine for longer periods than males. If carcinogens are present in the urine which contribute to TCC, this could explain the increased incidence in female dogs.

Rarely, cases have been linked to the use of cyclophosphamide, a chemotherapy drug. A 2004 study also showed that exposure to phenoxy herbicide treated lawns increased the risk of developing TCC in the Scottish Terrier [1]. Chronic exposure to hydrocarbons, present in cigarette smoke, may also play a role in the development of TCC.

Bladder leiomyosarcoma and rhabdomyosarcoma are typically considered idiopathic, meaning the underlying cause is unknown.

Bladder Cancer Symptoms in Dogs

As mentioned, bladder cancer can mimic more common conditions such as UTIs or urinary bladder stones. 

The three most common symptoms of bladder cancer in dogs include:

• Passing small amounts of urine more frequently than usual (pollakiuria)
• Blood in the urine (hematuria)
• Straining to urinate (stranguria)

Signs that may be seen occasionally include:

• Straining to defecate (tenesmus)
• Painful abdomen
• Distended abdomen

Rarely, your dog may develop hypertrophic osteopathy, which is an interesting syndrome in which there is bony proliferation on the leg bones in response to the presence of a mass in the chest or abdomen. This causes thickening of the leg bones and limping. Treatment usually involves pain control and tumor management.

If you notice symptoms in your dog, it’s important not to panic! Remember that bladder cancer is not the most common cause of frequent urination, bloody urine, or straining to urinate. These symptoms are also the typical signs of both UTIs and bladder stones, which are significantly more common than bladder cancer. However, dogs with bladder cancer may develop secondary UTIs, so it’s important to rule out a tumor if signs do not resolve or promptly recur after treatment with appropriate antibiotics.

Straining to defecate can also have many causes, such as diarrhea, constipation, anal sac infection, and more. Abdominal distention and tenderness are also signs of more common conditions affecting the abdomen, such as a mass of the spleen, constipation, bowel obstruction, and more.

If you note any symptoms of bladder cancer, you should have your dog examined by a veterinarian. Although other causes are more likely, these symptoms still require prompt veterinary attention.

Dog Bladder Cancer Diagnosis

Most bladder cancers will require advanced diagnostics beyond a simple physical examination.

If your pet is frequently urinating small amounts, straining to urinate, or has blood in their urine, your veterinarian will likely recommend a urinalysis with culture and radiographs (X-rays). The urinalysis with culture determines if there is a urinary tract infection and what antibiotics should be used. Occasionally, the urinalysis may be suggestive of TCC, with about 30 percent of TCCs shedding tumor cells into the urine that can be seen under the microscope.

Most bladder tumors are not visible on X-rays, so this test is used for ruling out other causes of the symptoms rather than confirming a bladder tumor. Some bladder stones are also not visible on X-rays.

If your veterinarian does not see stones on X-rays and the urinalysis is suggestive of a urinary tract infection, they will likely begin by treating the UTI. If the UTI does not completely resolve or quickly recurs, this warrants further investigation to rule out a bladder tumor.

Ultrasonographic examination of the abdomen is very effective for detecting a bladder tumor and ruling out bladder stones. Although some stones don’t show up on radiographs, all stone types can be seen on ultrasound. An ultrasound exam can significantly raise the suspicion for bladder cancer but does not confirm the type of tumor present. If your veterinarian has access to ultrasound, you may consider requesting this rather than X-rays. If your dog has a confirmed bladder tumor, abdominal ultrasound can also be used to monitor for spread of the cancer. To examine the lungs for spread, your veterinarian may do chest X-rays.

If your dog has the signs of bladder cancer, is older, and has a mass visualized in the neck of the bladder on ultrasound, this may be enough to presumptively diagnose TCC. Definitive diagnosis requires a biopsy or collection of cells. If your dog has ever had a skin mass, you may have seen your veterinarian place a needle into the tumor to collect a sample of cells. This is called a fine needle aspirate (FNA). FNA is typically not recommended for suspected TCC. This specific tumor is well-known for seeding to other organs via needle track, so performing FNA of a TCC increases the risk of spread.

Even without FNA, veterinarians can still collect a sample. Your family veterinarian may do a cystotomy surgery, meaning they enter through the abdomen, cut the bladder open, and take a sample of the tissue. This is the most invasive method. Instead, they may attempt traumatic catheterization, which is when a urinary catheter is inserted with the goal of agitating the tumor and releasing cells into the urine for collection.

Specialty or referral veterinary hospitals may have access to advanced techniques, such as cystoscopy. Cystoscopy is the use of a small camera inserted through the urethra to examine the inside of the bladder. A biopsy may be taken via cystoscopy for confirmatory testing. Importantly, the urethra must be large enough for the camera, so this technology is limited in very small animals.

Urine can also be collected for a BRAF or BRAF PLUS test, which detects cells that have the genetic mutation present in TCC cancer cells. The BRAF mutation test can sometimes detect the tumor before it is visible on imaging. Pet parents may consider using this test to screen their apparently normal dogs who belong to at-risk breeds. If the BRAF mutation test is negative but the veterinarian still suspects TCC, they may recommend a BRAF-PLUS test, which also uses urine. Together, BRAF and BRAF-PLUS can detect 95 percent of dogs with TCC. This test is not the same as the BLAT (bladder tumor antigen test), which wasn’t accurate in bloody urine, a common clinical sign of TCC.

Dog Bladder Cancer Treatment

Because of the unfortunate location that TCC tends to develop in, as well as the highly invasive nature of this tumor, bladder cancer treatment is rarely curative and is instead aimed at controlling the clinical signs and promoting a good quality of life.

For most dogs, surgery isn’t an option. Surgery in the neck of the bladder risks damage to the urethra and ureters and is likely to cause incontinence without successfully removing the entirety of the tumor. Surgery may be attempted if the tumor develops in a different part of the bladder. With these surgeries, a significant portion of the bladder is removed. The pet would have reduced storage capacity in the remaining bladder, and 80 percent of surgeries result in recurrence.

Medical treatment is the most common method for treating bladder cancer. Up to 40 percent of dogs have a response to medical therapy, though they typically don’t achieve complete remission. Successful treatment in this scenario means either the tumor shrinks or the tumor growth slows.

Medical treatment frequently involves the use of a non-steroidal anti-inflammatory drug (NSAID) with anti-cancer activities, such as piroxicam, deracoxib, or firocoxib, either alone or in combination with chemotherapy agents. Chemotherapy protocols may vary between oncologists, but examples of chemotherapy agents that may be used include mitoxantrone, carboplatin, vinblastine, and cisplatin. Typically, a chemotherapy agent is given every couple weeks for a predetermined number of treatments as long as it’s well-tolerated by the dog. 

Importantly, dogs typically handle chemotherapy better than humans do. With cancer treatment in pets, we aim for maintaining quality of life rather than quantity of years. Veterinarians won’t tolerate your dog feeling poorly and will ensure chemotherapy isn’t negatively impacting their quality of life. Your dog is unlikely to experience the vomiting and nausea, lethargy, or hair loss that is seen in people.

In the past, radiation wasn’t considered a good option for pets because of damage to structures around the bladder, such as the colon. However, radiation therapy has become more precise and is now considered a better option for TCCs, although access to radiation treatment is limited. If you are interested in radiation as an option, this will likely require travel.

You may find information about removal of the entire bladder in cases of TCC. With this surgery, the ureters are attached to the colon so the pet passes urine with stool or to the vagina in female animals. There is a high risk of complications, including ascending bacterial infection and scarring of the ureters leading to obstruction, both of which could lead to kidney infection. Patients require long-term use of antibiotics, frequent blood monitoring for evidence of kidney injury, and free access to an area for urination due to incontinence. You’re unlikely to find a veterinarian who recommends or is willing to perform this surgery, as the pet’s quality of life can be significantly impacted. Keep in mind that TCCs are likely to metastasize, and removal of the bladder does not address spread of the cancer.

If the tumor is obstructing the urethra, an option would be to have a urethral stent placed using fluoroscopy at a specialty veterinary clinic so that the pet can urinate. This procedure carries the risks of recurrent urinary tract infections and incontinence but can restore comfort for your dog. Not all specialty centers perform this procedure. If your veterinarian is recommending it, they should direct you to a facility that can assist you.

Another option is a permanent urinary catheter. A permanent urinary catheter significantly increases the risk of bladder infections, so frequent urine cultures are needed. Pet parents will need to empty the bladder with a drainage tube multiple times per day, and the catheter must be kept clean. If the tube becomes dislodged, this can have serious consequences for the pet. Maintenance of a permanent urinary catheter can be very taxing on pet parents, affecting their pet’s quality of life and the human-animal bond.

Regardless of the treatment pursued, expect frequent follow-ups, urinalyses, urine cultures, bloodwork, and repeat imaging to monitor treatment success, tumor size, cancer spread, and systemic health.

Cost to Treat Bladder Cancer in Dogs

The cost to treat bladder cancer varies widely depending on the treatment. Conservative treatment with piroxicam may be around $2,000. 

If you pursue advanced diagnostics and treatment at a referral center (chemotherapy, radiation therapy, stents, etc.), treatment can come to well over $10,000. 

Don’t forget to check out clinical trials at universities, which can increase the affordability of treatment while advancing cancer treatment for future canine family members. 

Dog Bladder Cancer Prognosis

Ultimately, most dogs diagnosed with TCC will pass due to the cancer.  Bladder cancer is locally aggressive and has a high potential to metastasize (spread) to other areas of the body. In the final stages of bladder cancer in dogs, the tumor can grow large enough that it obstructs the urethra or ureters, resulting in kidney failure due to the inability to pass urine.

With NSAID treatment alone, the expected survival time is approximately 6 months. Adding chemotherapy to the NSAID can increase survival time to 9-11 months. Survival time varies depending on patient age, extent of local tumor invasion, and presence of metastases. 

Your veterinarian will work with you to ensure your pet has a good quality of life throughout the treatment protocol.

How to Prevent Bladder Cancer in Dogs

Keeping in mind that many cases of TCC don’t have a known underlying cause, there is no guarantee that you can prevent bladder cancer in your dog. 

However, based on the known risk factors for developing TCC, there are steps you can take to reduce the likelihood of developing this tumor, especially in at-risk breeds. Recommendations for prevention include:

• Feeding yellow/orange or green leafy vegetables at least three times per week [2]
• Avoiding older generation flea control products like flea dips
• Avoiding lawns treated with herbicides and pesticides
• Limiting exposure to secondhand smoke
• Preventing obesity in your pet

In at-risk breeds, you could consider BRAF testing at regular intervals, potentially detecting the tumor before your pet has clinical signs.

It’s never easy to face a diagnosis of cancer in your pet, and a diagnosis of a less common cancer like bladder cancer can make you feel alone and afraid. Your veterinary team can help support you and your pet during this time and may have recommendations for support groups or grief counselors if needed.