Signs of Bladder Cancer in Dogs: What to Watch For

The most common signs of bladder cancer in dogs are blood in the urine, straining to pee, peeing small amounts often, and accidents in the house (Knapp, 2022). Those are the same signs a urinary tract infection (UTI) causes. That's why bladder cancer is easy to miss. If urinary signs keep coming back after antibiotics, ask your vet about checking for cancer.

The usual type is called urothelial carcinoma, also known as transitional cell carcinoma (TCC). It's most often found in older dogs, more often in females, and much more often in certain breeds, especially Scottish Terriers (Knapp et al., 2020). Later signs can include a weak urine stream, trouble passing stool, belly pain, and limping if the cancer spreads to bone (Knapp, 2022; Penn Vet Ryan Hospital, 2017; Henry, 2007). A dog who strains but can't pass any urine needs emergency care.

Key Points

• Bladder cancer makes up about 1.5% to 2% of cancers in dogs (Knapp et al., 2020).
• Blood in the urine is the most common sign (Knapp et al., 2020).
• Straining, peeing often, and accidents are also common (Knapp, 2022).
• A UTI causes the same signs. About 55% of dogs with this cancer also have a positive urine culture, so a dog can have both at once (MSPCA-Angell, 2026).
• Signs may get better on antibiotics even when cancer is the cause (Henry, 2007).
• Scottish Terriers have about 20 times the risk of mixed-breed dogs (Knapp et al., 2020).
• Most dogs are 9 to 11 years old when diagnosed (Knapp et al., 2020).
• About 16% to 20% of dogs already have spread when they're diagnosed (Knapp et al., 2020; Knapp, 2022).
• A dog who strains without passing any urine may have a blocked urethra. That's an emergency (Penn Vet Ryan Hospital, 2017).

Detailed Explanation

Signs of bladder cancer in dogs at a glance

Sources for this table: Henry (2007), Knapp (2022), Knapp et al. (2020), MSPCA-Angell (2026), and Penn Vet Ryan Hospital (2017). Each sign is explained below.

What is bladder cancer in dogs?

Most bladder cancer in dogs is urothelial carcinoma. You'll also see it called transitional cell carcinoma, or TCC. It starts in the cells that line the bladder. More than 90% of these tumors are intermediate or high grade and grow into the bladder wall (Knapp et al., 2020).

Where it grows matters. Most tumors form in the trigone, the neck of the bladder where urine flows out. In more than half of dogs, the tumor reaches into the urethra, the tube that carries urine out of the body. In male dogs, 29% have tumor in the prostate (Knapp et al., 2020). That location helps explain the signs. A tumor at the bladder's exit can irritate the bladder, bleed, and slowly narrow the path urine has to take. Our bladder cancer in dogs page covers the disease from diagnosis through care, and our article on transitional cell carcinoma goes deeper into this tumor type.

What are the early signs of bladder cancer in dogs?

The early signs are all about peeing. Watch for:

• Blood in the urine. It may look pink, red, or brown, or show up as spots on bedding or snow. This is the most common sign (Knapp et al., 2020).
• Straining. Your dog squats or lifts a leg for a long time and little comes out (Knapp, 2022).
• Peeing often, with many trips outside or many small attempts on one walk (Knapp, 2022).
• Accidents in the house. A house-trained dog may suddenly leak or pee indoors (Knapp, 2022).
• Pain when peeing. Some dogs whine, look back at their belly, or seem uncomfortable (Penn Vet Ryan Hospital, 2017).

None of these signs is specific to cancer. Bladder stones and infections cause them too. What matters is the pattern. Signs that linger, come back, or don't fully clear up deserve a closer look. For a broader list of warning signs, see our guide to early signs of cancer in dogs.

Is it bladder cancer or a UTI?

This is the question most owners are really asking, and the honest answer is that you can't tell from the signs alone. A urinary tract infection causes the same signs (Knapp, 2022). Worse, many dogs with bladder cancer have an infection too. About 55% have at least one positive urine culture at the same time (MSPCA-Angell, 2026).

That overlap causes real delays. Dogs often feel better on antibiotics, so the improvement gets taken as proof of a simple infection (Henry, 2007). Meanwhile, the tumor keeps growing (MSPCA-Angell, 2026). A history of urinary tract infections is common in dogs who are later diagnosed with bladder cancer (Knapp et al., 2020).

Here are the clues that should prompt your vet to look further:

Oncologist Dr. Carolyn Henry advises that vets should have a raised index of suspicion for bladder cancer in older dogs with urinary signs (Henry, 2007). If your dog fits several of these clues, it's fair to ask, "Could this be more than an infection?" Our article on symptoms you should never ignore has more examples of signs that deserve a second look.

What are the later signs of bladder cancer in dogs?

As the tumor grows or spreads, other signs can appear.

A weak stream or no urine at all

If the tumor blocks the urethra, your dog may strain hard and pass only a dribble, or nothing (Penn Vet Ryan Hospital, 2017). A complete blockage is an emergency.

Trouble passing stool

Some dogs strain to poop, not just to pee (Henry, 2007). It's easy to mistake for constipation, so mention it to your vet if it shows up alongside urinary signs.

Belly pain and kidney problems

A tumor can block a ureter, one of the tubes that carries urine from a kidney to the bladder. Urine then backs up, and the kidney swells. That can cause belly pain, and your vet may feel a large kidney (MSPCA-Angell, 2026).

Limping

Bladder cancer can spread to bone. It can also cause a condition called hypertrophic osteopathy, which makes the leg bones swollen and painful (Knapp, 2022). So if an older dog with urinary signs starts limping, mention both problems at the same visit, even if they seem unrelated. Our article on cancer in a dog's leg explains other causes of limping.

Tiredness, weight loss, and poor appetite

These general signs can show up too. Our guides to weight loss and hidden pain can help you spot these changes early.

Can a dog have bladder cancer without blood in the urine?

Yes. Blood in the urine is the most common sign, but it isn't the only one (Knapp et al., 2020). Some dogs show straining, frequent peeing, or accidents first (Knapp, 2022). And some dogs have no signs at all when the cancer is found. Screening of Scottish Terriers turned up bladder cancer before any signs appeared (Knapp, 2022). In one clinic's experience, the BRAF urine test picked up the cancer more than 4 months before signs began (MSPCA-Angell, 2026). So clear-looking urine doesn't rule bladder cancer out.

Is bladder cancer painful for dogs?

It can be. Some dogs find peeing painful early on (Penn Vet Ryan Hospital, 2017). Pain and a sense of urgency usually become more noticeable as the disease goes on (Knapp et al., 2020). A blocked ureter can cause belly pain (MSPCA-Angell, 2026), and spread to bone or hypertrophic osteopathy can make legs sore (Knapp, 2022). Dogs are good at hiding discomfort, so changes in behavior matter. Tell your vet about any change you notice, because there are ways to keep a dog with bladder cancer more comfortable. Our pain management guide covers the options your vet may suggest.

How fast does bladder cancer progress in dogs?

It varies a lot from dog to dog. Most of these tumors are intermediate or high grade and grow into the bladder wall (Knapp et al., 2020). Without treatment, most dogs die from complications of the cancer within a few to several months (Penn Vet Ryan Hospital, 2017). Spread is less common early on, but it becomes common later. About 16% to 20% of dogs have detectable spread at diagnosis, compared with 50% to 60% by the end of life (Knapp et al., 2020; Knapp, 2022). That's one more reason not to wait when urinary signs keep coming back.

Which dogs are most at risk?

Any dog can get bladder cancer, but some have much higher odds. Scottish Terriers stand out, with about 20 times the risk of mixed-breed dogs (Knapp et al., 2020). Shetland Sheepdogs, Beagles, West Highland White Terriers, and Wire Hair Fox Terriers have 3 to 5 times the risk of other dogs (Knapp, 2022). Our article on cancer in Scottish Terriers covers that breed in detail.

Females are diagnosed more often than males, at a ratio of about 1.7 to 1.95 females for every male. Spayed and neutered dogs have roughly twice the risk of intact dogs (Knapp et al., 2020). Most dogs are diagnosed between 9 and 11 years old, though some are as young as 4 to 6 (Knapp et al., 2020).

Environment plays a part too. In Scottish Terriers, exposure to lawns treated with chemicals was linked to about 7 times the risk. Eating vegetables at least three times a week was linked to about 70% lower risk (Knapp et al., 2020). A healthy weight helps too (Knapp, 2022). Our articles on lawn pesticides and herbicides and cancer risk factors explain more.

How do vets check for bladder cancer?

It usually starts with a urine test and a urine culture. If cancer is a concern, imaging comes next. Ultrasound can show a mass in the bladder, and X-rays of the chest look for spread (Knapp, 2022; Penn Vet Ryan Hospital, 2017). Our articles on ultrasound and X-rays explain what each one shows.

A urine test called CADET BRAF looks for a genetic change found in most of these tumors. In the study behind it, the test was 85% sensitive and 100% specific for this cancer and for prostate cancer (Mochizuki et al., 2015, as cited in Ettinger, 2019). In plain terms, a positive result is very reliable, but a negative result doesn't rule cancer out. About 15% of these tumors don't carry the change (MSPCA-Angell, 2026). One clinic reports the change showed up in urine more than 4 months before signs began in screened dogs (MSPCA-Angell, 2026). Purdue's bladder cancer team still cautions that urine tests can give false results and can't replace a biopsy (Knapp, 2022). Our article on the BRAF test walks through it.

A biopsy confirms the diagnosis. It's usually taken with a scope passed into the bladder, or with a urinary catheter (Knapp, 2022; Boston, n.d.). Needle aspirates of the bladder mass are generally avoided. Tumor cells have been carried along the needle path in some dogs, so specialists don't recommend this approach when there's another option (Boston, n.d.; Henry, 2007; Vignoli et al., 2007). If you're wondering why a sample sometimes doesn't give a clear answer, see our article on whether a biopsy always gives a diagnosis.

Where does bladder cancer spread in dogs?

The most common places are the lymph nodes in the pelvis, the lungs, and bone (Penn Vet Ryan Hospital, 2017). Often, it hasn't spread yet when it's found. About 16% to 20% of dogs have spread that can be found when they're diagnosed, though by the end of life 50% to 60% do (Knapp et al., 2020; Knapp, 2022). That's why your vet will likely recommend staging, which usually includes chest X-rays and abdominal imaging (Knapp, 2022). Our guide to whether a dog's cancer has spread explains what those results mean.

Can bladder cancer in dogs be found early?

Sometimes. In a 3-year study of 120 Scottish Terriers, screening found bladder cancer before any signs appeared, and early cancers responded better to treatment (Knapp, 2022). Purdue offers bladder ultrasound screening for Scottish Terriers, West Highland White Terriers, Beagles, and Shetland Sheepdogs age 6 and older (Purdue University College of Veterinary Medicine, 2026). If you share your life with a high-risk breed, ask your vet whether regular urine checks or ultrasound make sense. Our article on cancer screening for dogs covers other options. Between visits, our 10-minute dog cancer check can help you build a habit of looking your dog over.

How long can a dog live with bladder cancer?

With treatment, average survival ranges from about 6 months to about 1 year, depending on where the tumor is (Penn Vet Ryan Hospital, 2017). Most bladder tumors in dogs sit at the neck of the bladder, where surgery usually can't remove them completely (Knapp et al., 2020; Knapp, 2022). Treatment usually focuses on slowing the cancer and keeping your dog comfortable. Common options include anti-inflammatory drugs and chemotherapy (Knapp, 2022). With these treatments, average survival is about 1 year when the tumor is in the bladder. It's about 6 months when the prostate or urethra is involved (Penn Vet Ryan Hospital, 2017). Dogs whose cancer has spread beyond the bladder also tend to have shorter survival (Knapp, 2022). These are averages, not promises. Our article on how long dogs live with cancer explains how to read survival numbers.

Our article on why bladder cancer is hard to treat explains the options. Our page for owners whose dog was just diagnosed is a good next stop. A veterinary oncologist can help you weigh the choices. If cost is a worry, our guide to the cost of treating cancer in dogs can help you plan ahead.

When to Contact a Veterinarian

Go to an emergency vet right away if your dog:

• Strains to pee and passes no urine, or only a few drops.
• Has a swollen, painful belly, is vomiting, or seems very weak.

Make an appointment soon if your dog:

• Has blood in the urine, even once.
• Is straining, peeing more often, or having accidents.
• Has urinary signs that come back after antibiotics, or never fully clear.
• Is a high-risk breed and has any change in peeing habits.
• Is straining to pass stool, limping, or losing weight along with urinary signs.

If you can, bring a fresh urine sample in a clean container and note when the signs started. Our checklist of what to bring to appointments has other things worth packing.

Questions to Ask Your Veterinarian

• Could these signs be bladder cancer, not just an infection?
• Should we run a urine culture before starting antibiotics?
• If the signs come back after antibiotics, what's the next step?
• Would an ultrasound of the bladder help?
• Is the BRAF urine test a good option for my dog?
• If we need a biopsy, how will you collect it?
• Is my dog's breed at higher risk?
• Should my dog have regular screening?
• If it is cancer, has it spread?
• Should we see a veterinary oncologist?

Our full list of questions to ask your vet has more ideas.

Sources

Boston, S. (n.d.). Transitional cell carcinoma in dogs [Conference proceedings]. https://hp.brs.nihon-u.ac.jp/~vetsurg/haihu/data/2018-11-04_Kaigai_DrSarahBoston/Transitional%20Cell%20Carcinoma%20in%20Dogs%20Proceedings.pdf 

Ettinger, S. (2019, July 29). Urine luck: A new test for canine bladder and prostate cancer. dvm360. https://dvm360.com/view/urine-luck-new-test-canine-bladder-and-prostate-cancer

Henry, C. J. (2007). Transitional cell carcinoma. Proceedings of the World Small Animal Veterinary Association World Congress. https://www.vin.com/doc/?id=3860788

Knapp, D. W. (2022). Canine bladder cancer. Purdue University College of Veterinary Medicine. https://www.vet.purdue.edu/wcorc/documents/CanineUrinaryBladderCancer.pdf

Knapp, D. W., Dhawan, D., Ramos-Vara, J. A., Ratliff, T. L., Cresswell, G. M., Utturkar, S., Sommer, B. C., Fulkerson, C. M., & Hahn, N. M. (2020). Naturally-occurring invasive urothelial carcinoma in dogs, a unique model to drive advances in managing muscle invasive bladder cancer in humans. Frontiers in Oncology, 9, Article 1493. 

Mochizuki, H., Shapiro, S. G., & Breen, M. (2015). Detection of BRAF mutation in urine DNA as a molecular diagnostic for canine urothelial and prostatic carcinoma. PLoS ONE, 10(12), e0144170. 

MSPCA-Angell. (2026, March 2). A new approach to diagnosing transitional cell carcinoma in dogs. https://www.mspca.org/angell_services/transitional-cell-carcinoma-in-dogs/

Penn Vet Ryan Hospital, Comprehensive Cancer Care Service. (2017). Transitional cell carcinoma in dogs [Client handout]. University of Pennsylvania School of Veterinary Medicine. https://www.vet.upenn.edu/wp-content/uploads/2025/05/transitional-cell-carcinoma-in-dogs.pdf

Purdue University College of Veterinary Medicine. (2026, August 25). Bladder cancer screenings. Werling Comparative Oncology Research Center. https://www.vet.purdue.edu/wcorc/bladder-cancer-screenings.php

Vignoli, M., Rossi, F., Chierici, C., Terragni, R., De Lorenzi, D., Stanga, M., & Olivero, D. (2007). Needle tract implantation after fine needle aspiration biopsy (FNAB) of transitional cell carcinoma of the urinary bladder and adenocarcinoma of the lung. Schweizer Archiv für Tierheilkunde, 149(7), 314-318. 

This article is provided for educational purposes only and does not constitute veterinary medical advice, diagnosis, or treatment. Figures from published studies describe groups of dogs and can't predict what will happen with an individual dog. If your dog has blood in the urine, is straining, or has urinary signs that keep coming back, contact your veterinarian.