Reviewed by Dr. Danielle Morosco, DVM (December 5, 2022)
Canine cancer is an experience no pet parent should have to go through. Unfortunately, our pets can experience many of the same cancers that we do. If you’re like most pet parents, you may worry when something doesn’t quite seem right.
If you’re concerned about your dog, you should know that bladder cancer is not a common cancer in dogs. That doesn’t mean you should ignore unusual signs of illness in your dog.
The exact cause of bladder cancer in dogs isn’t fully understood, but there are some theories on what could bring it on.
Keep reading to learn more about potential causes of bladder cancer in dogs, signs, how a diagnosis is made, treatment options, and life expectancy.
What is Bladder Cancer in Dogs?
Cancer occurs when old cells don’t die off naturally. Instead, the uncontrolled growth of cells takes over. When this happens, cancer cells are created. This overpopulation of unwanted cells ends up forming a clump that then becomes a tumor.
Bladder cancer can affect the urinary tract as well as the dog’s kidneys, ureters, urinary bladder, prostate, or urethra depending on whether the dog is male or female.
This cancer is rare, but for dogs who have it, there is a chance it will spread to the organs. Thankfully, bladder cancer only affects a very small percentage of dogs.
What is Transitional Cell Carcinoma (TCC)
Transitional cell carcinoma (urothelial carcinoma) is the most common type of bladder cancer in dogs.
TCC is a malignant tumor that develops from the transitional epithelial cells that line the bladder walls.
However, if bladder cancer is diagnosed, the malignant tumors of TCC are most likely to be found. These tumors take an otherwise healthy bladder and block the urethra. The cells begin to accumulate and attach to the bladder lining. Eventually the tumors can totally block urine flow.
In severe cases of urethra blockage, the dog can succumb to kidney damage or kidney failure. If your dog cannot urinate at all, it is a medical emergency.
Less common bladder tumors include:
- Leiomyosarcoma
- Fibrosarcoma
- Other soft tissue tumors
Common dog cancers in general include:
- squamous cell carcinomas
- mast cell tumors
- hemangiosarcoma
- osteosarcoma
- fibrosarcoma
- lymphoma
- melanoma
Can Bladder Cancer in Dogs Spread to Other Parts of the Body?
The malignant tumors of TCC will eventually spread to other parts of the body. The only way to stop the spread would be to diagnose the disease and treat it before it has a chance to spread. Unfortunately, symptoms can be vague, and the cancer has usually already spread by the time a diagnosis is made.
Unfortunately, about 20% of dogs with bladder cancer have signs that the cancer has spread. This type of cancer can show up in the kidney, ureters, prostate or the vagina.
Metastasis (meaning the cancer has spread) can show up in the lungs, lymph nodes, bones, and other organs.
Dog Breeds Prone to Bladder Cancers
Bladder cancer is statistically rare in dogs. That said, there are some breeds of dogs that appear to be more at risk. These include:
- · Shetland sheepdogs
- · Scottish terriers
- · Wire Hair fox terriers
- · West Highland white terriers
- · Beagles
Other Risk Factors
Veterinarians aren’t entirely sure what increases the risk factor for dogs. However, there is some thought that breeds more prone to obesity may be at increased risk. Environmental risks (exposure to toxins, pesticides, etc.) could also be at play.
In some cases, there may be a genetic predisposition.
Age is a common risk factor for bladder cancer and many cancers in dogs as most are diagnosed between the ages of 6 and 11.
If you believe your dog is at risk, ask about the CADET Braf test. This test can help veterinarians detect the presence of certain specific gene mutations that might have a link to bladder cancer. In fact, it can also be useful in detecting bladder cancer long before the signs emerge.
This revolutionary test detects the mutation that causes bladder cancer and non-invasive. It only involves free catching a certain amount of urine from your dog.
Signs and Symptoms of Bladder Cancer
Bladder cancer can be hard to detect. The reason is because many of the signs can mimic other conditions including urinary tract infections, kidney infections, bacterial infection and bladder stones.
Clinical signs of bladder cancer include:
- bloody urine
- cloudy, foggy, or discolored urine
- cystitis (inflammation of the bladder)
- Straining or inability to urinate
- Frequent accidents in the home (urination)
- Weight Loss
- Poor appetite
- Coughing
- not interested in regular exercise
Diagnosing Bladder Cancer in Dogs
Because bladder cancer is rare in dogs, it may not be the first thing on the veterinarian’s mind. Signs of the disease mimic many less-serious conditions. In the early stages, your dog may be treated for a urinary tract infection (for example).
When the prescribed treatment doesn’t work, it becomes clearer to the veterinarian that there may be something else at play. In order to reach a definitive diagnosis of bladder cancer, the following tests may be ordered:
Blood work
Ordering a minimum database (including chemistry panel and complete blood count) is a common tool used to determine whether there is something going wrong in the body.
Unfortunately, it doesn’t always paint a clear picture. This is because the blood work can come back normal unless kidney function is impaired.
Urinalysis
Sometimes dogs with bladder cancer excrete cells in their urine. This urine test can screen for those cells. The one drawback is that inflammation in the urinary tract from any kind of infection can cause similar-looking cells to show up.
Remember that it’s the combination of tests that help determine the diagnosis, not any one test.
Abdominal Ultrasound
Abdominal imaging is a way for veterinarians to see if the cancer has spread to the abdominal organs. Veterinarians will often look at the bladder with the ultrasound to see if there is a tumor and to evaluate the bladder wall thickness and appearance. It can also help detect tumor size and whether there is any bladder swelling.
Ultrasound can also be used to determine the size of the tumor and the size of the lymph nodes. Enlarged lymph nodes may be a sign of metastasis. However, enlarged lymph nodes can also be a sign of other conditions.
Chest Radiograph (x-ray)
Once bladder cancer extends beyond the lymph nodes, it tends to find its way to the lungs. A chest x-ray can help determine whether or not the cancer has spread.
Veterinary Bladder Tumor Antigen Test
The VBTA test is a non-invasive urine screening test for dogs. These will test for tumor antigens that can be present in bladder or prostate cancer.
It is carried out by testing urine samples. One of the downsides of this test is the potential for a false negative (the dog has bladder cancer, but the BRAF test comes back negative). However, the accuracy when a dog does have bladder cancer is greater than 99.5%
“The sensitivity in detecting urothelial cancer in a dog with clinical signs is around 80%. The specificity of this test is >99.5%.
All cases that have the presence of this mutation have had histopathologic confirmation of urothelial carcinoma. Normal dogs, dogs with benign polyps or inflammation of the urinary tract will not harbor the BRAF mutation.
This means if the dog has a positive result, the dog has >99.5% chance that it most likely has urothelial carcinoma somewhere in the urinary tract. However, if the dog has a negative result, the dog can still have urothelial carcinoma, because around 20% of urothelial carcinomas do not possess BRAF mutation.
This test is not affected by the presence of blood, bacteria or protein in the urine. “
https://www.thepetoncologist.com/blog/transitional-cell-carcinoma
Tissue Biopsy
This is the most definitive test for your canine to be diagnosed with bladder cancer. Although invasive, it can be the most effective tool for diagnosis.
Tissue biopsies can be obtained more than one way. One is through a surgical biopsy and the other uses an ultrasound-guided urinary catheter. In some cases, female dogs may undergo a cystoscopy. This means that a special camera is inserted into the bladder.
The benefit of cystoscopy is that the tumor can be directly seen and biopsied at that time.
Common Treatment Options
The following is an outline of standard treatments used to treat urinary bladder cancer in dogs.
Surgical Removal of the Tumor
Unfortunately, surgical intervention may not be a good option. The reason for this is because of the location of the tumors. They tend to appear in sensitive areas that could be damaged by surgery. By the time obvious signs are observed, the tumor is usually too large to safely remove.
Laser Ablation Therapy
Laser ablation therapy is sometimes used as a palliative treatment. This treatment isn’t a cure but it can improve quality of life. In fact, it may even prolong survival time. The procedure is done through a cystoscope using ultrasound guidance. Recovery time is relatively fast.
Chemotherapy for Bladder Cancer in Dogs
Dogs respond well to chemotherapy when they have other types of cancer. Unfortunately, chemotherapy treatment doesn’t seem to work well in pets. Less than 20% of pets will respond adequately to chemotherapy.
In the rare case where chemotherapy is used, it’s usually in combination with oral nonsteroidal anti-inflammatories (NSAIDs). Typical medications used for this include meloxicam (brand name: Metacam) and piroxicam (brand name: Feldene).
Keep in mind that dogs do not experience chemotherapy the same way that we do. In fact, it’s thought that chemotherapy is less toxic in dogs. *Source – vet.purdue.edu – Canine Bladder Cancer by Deborah W. Knapp, DVM, Dipl. ACVIM
Radiation Therapy for Dogs with Bladder Cancer
Some studies show that radiation may work better than chemotherapy in treating bladder cancer in dogs. Unfortunately, it can also come with serious side-effects.
When radiation is administered, there are what’s known as the early side effects (within 2 weeks after the start of treatment) and late effects.
Early side effects of radiation in dogs can include:
- · Redness of the skin
- · Irritation of the skin
- · Ulceration (moist desquamation)
- · Diarrhea
- · Loss of bladder control
- · Bleeding from the rectum
- · Increased need to urinate
- · Blood in the urine
Late side effects of radiation in dogs can include:
- · Muscle fibrosis
- · Skin fibrosis
- · Bone necrosis (cell death)
- · Bone fracture
Can Bladder Cancer in Dogs be Prevented?
It’s impossible to totally remove the risk of bladder cancer in dogs. However, pet owners may want to keep their dogs away from pesticides (yard sprays, for example), maintain regular veterinary checkups, and feed your dog a high-quality diet.
Unfortunately, there’s no sure-fire way to guarantee your dog won’t get bladder cancer. It should be reassuring to note that it is rare.
Life Expectancy of Dogs with Bladder Cancer
Median survival time for dogs with bladder cancer is low. With appropriate treatment, dogs can live between 6 and 12 months longer than if they receive no treatment.
Dogs who receive no treatment will live anywhere from 4 to 6 months. Keep in mind that these are general guidelines. Every dog is different. Ultimately, the prognosis will depend on things like:
- · Location of the tumor
- · Age of your dog
- · Tumor Size
- · Any other underlying conditions your dog may have
- · Tumor growth rate
- · Whether the cancer has spread at the time of diagnosis
Ultimately, treatment and medication can improve quality of life. The best thing to do is talk with your veterinarian to determine the best option.
Get a Second Opinion
If you have already brought your dog to a veterinarian and need a second opinion, there are a few things you can do.
1. Ask for a referral to another veterinarian. Friends and family may be able to make a good recommendation.
2. Search nearby veterinarian clinics in your neighborhood and book an appointment as soon as possible.
3. Talk to a veterinarian online. Naturally, a veterinarian cannot do a physical examination online. However, they can listen and make recommendations based on the dog’s signs and medical history.
IMPORTANT: You are in your right to get a second opinion. That said, do not delay treatment for your dog. If you can speak to another veterinarian (online or in person) make sure it’s done as quickly as possible.
More Posts You Might Be Interested In:
Mast Cell Tumor Dog Life Expectancy
Summing It Up
At the end of the day, bladder cancer is an unfortunate and devastating illness. If your dog is experiencing any of the signs noted in this post, try not to worry. Remember that bladder cancer in dogs is rare.
If you want some peace of mind, you might consider asking your vet for a CADET Braf test as mentioned earlier. These tests can sometimes detect hints of cancer long before the signs begin to emerge. It can also help detect whether your dog has a specific gene mutation that may cause bladder cancer in the future.
Early diagnosis and treatment give your dog the best chance of a good outcome.
I want to thank you for taking the time to read this post. I am not a licensed veterinarian and I ask that you use this information as a starting point. Clarify issues with your veterinarian and always follow his/her advice over any post you read on the Internet.
Please be sure to come back because we have loads of new posts ready to be published!
SOURCES:
What is Cancer – Cancer Treatment Centers of America
VeterinaryCancer.com – Radiation Therapy
Memphis Veterinary Specialists