Metastases can develop, but are not found in every cat at diagnosis. Local tumour growth and obstruction of urine flow can also cause a serious situation.
When to see a vet urgently
A cat with urinary symptoms needs immediate assessment if urine cannot pass or general health deteriorates:
- your cat repeatedly strains but passes no urine or only drops;
- difficulty urinating is accompanied by vomiting or marked tiredness;
- the abdomen seems painful and your cat loses their appetite;
- your cat becomes weaker rapidly or collapses.
A urinary obstruction cannot be dealt with by waiting at home. Find a vet near you for emergency care.
Overview
Transitional cell carcinoma develops from the urothelial cells lining the inside of the bladder and urinary tract. The tumour destroys the lining, causes inflammation and bleeding, and obstructs the bladder outlet and urethra. In its early stages, it may resemble chronic bladder inflammation, so it is often diagnosed late.
The term urothelial carcinoma, abbreviated to UC, is also used today. It means the same tumour type as TCC. Tumour location within the bladder varies more in cats than dogs. Treatment planning establishes whether the change extends into the urethra or the points where the ureters enter the bladder. Growth at these sites may hinder urine flow from the kidneys to the bladder.
Recurrent inflammatory symptoms do not always mean a recurrent bacterial infection. The tumour itself can irritate the bladder and bleed. However, a cat can have both a tumour and a bacterial infection. The precise cause of the urinary symptoms determines what treatment is needed.
Causes
- An inherited predisposition, with higher risk in some family lines.
- Chronic bladder inflammation, including recurrent cystitis and urinary stones.
- Exposure to carcinogens, such as pesticides, tobacco smoke and chemicals.
- Age, with older cats affected more often.
- Hormonal and metabolic factors described in veterinary literature, although their importance is not fully understood.
There is little research into the causes of this disease in cats. The inherited predisposition, chemical exposures and hormonal or metabolic factors listed should not be interpreted as established causes of feline urothelial carcinoma. Risk information from dogs or people cannot be applied directly to cats. Previous inflammation and a tumour occurring in the same animal also do not prove that inflammation caused the cancer.
Risk factors
- Cats older than 8–10 years.
- Cats with chronic bladder inflammation or urinary stones.
- Cats with long-term exposure to chemicals.
- Unlike dogs, cats show little evidence of a breed predisposition.
Older age is a common finding in published patient groups, but the age range above is not a diagnostic cut-off. The tumour can also occur in younger adults. Little is known about other independent risk factors in cats, and the risk in a cat without symptoms cannot be determined solely from previous urinary tract problems.
Typical symptoms
- blood in the urine, known as haematuria;
- frequent urges to urinate, known as pollakiuria;
- painful urination, or dysuria, with a straining posture;
- urinary incontinence or passing urine in drops;
- chronic, recurrent bladder inflammation;
- in later stages, weight loss, reduced appetite and lethargy.
Urinating outside the litter tray may be a sign of pain or urgency rather than deliberate behaviour. Monitor both the number of visits and whether urine actually passes. Visiting the litter tray alone does not show that the bladder is emptying.
Symptoms resemble those caused by urinary stones, bacterial infection and feline idiopathic cystitis, which causes bladder symptoms without another identifiable cause. Blood in the urine therefore cannot serve as a home test for cancer. A recurrent episode may also have a different cause from a previous one, so an old diagnosis does not replace a new assessment.
Complications and consequences
- urinary tract obstruction;
- enlargement of the renal pelvis and kidney failure;
- spread to the lymph nodes, liver and lungs;
- chronic pain and toxin build-up;
- death without treatment.
Here, toxin build-up may mean uraemia caused by an obstruction: waste products normally removed in urine accumulate in the body. An obstruction can also alter blood electrolyte balance and cause dangerous heart rhythm disturbances. A urethral obstruction prevents the bladder from emptying, whereas an obstruction of a ureter hinders urine flow from a kidney to the bladder. The kidneys are therefore assessed alongside the bladder.
Diagnosis at the vet
- routine urine testing for blood and abnormal cells;
- bladder ultrasound to look for tumours and wall thickening;
- cystoscopy and biopsy to confirm the diagnosis;
- X-rays or CT to assess spread;
- distinguishing the condition from bladder inflammation and urinary stones.
As well as the tumour, ultrasound assesses the bladder wall, ureters and kidneys. Imaging may suggest a tumour, but a cell or tissue sample may be needed to confirm the nature of the change. Abnormal cells in urine are also interpreted alongside inflammation and other findings. A urine culture helps establish whether a bacterial infection needing treatment contributes to the symptoms. Antibiotics are not chosen solely because there is blood in the urine.
The sampling method is planned according to the suspected change. Passing a needle through a tumour carries a possibility of spreading tumour cells, so the vet weighs the benefits and drawbacks of different methods. This does not mean automatically abandoning the need for a sample: a confirmed diagnosis helps select appropriate treatment.
Staging assesses the extent of local growth and possible spread to lymph nodes or distant sites. Not every cat needs every imaging test. Tests are chosen according to how the result would affect treatment options and the prognosis. Blood tests and the cat's other health conditions are also considered before treatment is selected.
Treatment
Options include removing the affected part of the bladder where possible, medical treatment and, in some situations, radiotherapy. Suitability for surgery depends particularly on the location and extent of the change. Not every tumour can be removed while preserving urinary tract function. The tumour can recur even after surgery, so monitoring is part of the plan.
An anti-inflammatory medicine may be considered as part of medical tumour treatment for some cats. This requires veterinary selection and monitoring because possible adverse effects and concurrent diseases affect suitability. There is less research on chemotherapy and radiotherapy in cats than on many treatments in dogs. Effectiveness cannot be promised on the basis of results in another species.
If the tumour obstructs the urinary tract, the first priorities are to secure urine flow and stabilise the cat. In some situations, a stent, a supporting structure that holds the passage open, can be placed in the urethra. It may relieve obstruction even if the tumour remains. Treatment may aim to ease symptoms and extend the time during which the cat can function comfortably.
What to monitor at home
Monitor urine output, pain, appetite and interest in normal activities. Pain may show as withdrawal and reduced grooming. Record changes so that the practice can assess the benefits of treatment in daily life. If eating declines, contact the vet treating your cat; do not force food into the mouth. Pain relief and control of nausea may be needed alongside cancer treatment itself.
Keep the litter tray clean and in a quiet, easily accessible place. A high rim can make access difficult for a weak cat. In a multi-cat household, make sure every cat can reach a tray without another blocking the way. A good litter tray environment makes toileting easier, but cannot relieve an obstruction caused by a tumour.
Prognosis
The prognosis is guarded. Tumour location, urinary tract patency, spread, other diseases and potential treatment adverse effects all matter. Studies of treated cats have found benefits from some approaches, but patient selection and incomplete follow-up in retrospective studies make results difficult to compare. Average survival in a study does not predict an individual cat's remaining time.
Palliative care, which relieves symptoms, remains active treatment even when the tumour cannot be removed. Agree in advance what to do if urination becomes difficult or pain increases. Quality-of-life assessment considers symptoms as well as the cat's ability to rest, eat and interact as they wish.
Prevention
- Reduce exposure to carcinogens, such as tobacco smoke, pesticides and household chemicals.
- Have chronic bladder inflammation and urinary stones treated promptly.
- Take older cats for regular health checks.
- Arrange bladder ultrasound if your cat has chronic urinary symptoms.
These measures have not been shown to reliably prevent feline bladder cancer. Investigating persistent symptoms nevertheless helps identify the cause and avoid repeatedly treating the same presumed inflammation. Ultrasound is an investigation for a cat with symptoms; on its own, it is not a validated cancer screening test for healthy cats.
Important for cat owners
Bladder cancer is a serious disease that often resembles ordinary cystitis in its early stages. Remember that long-standing recurrent bladder inflammation or blood in the urine needs thorough investigation. Finding a tumour early offers an opportunity for treatment, including surgery, chemotherapy and supportive care, better quality of life and a longer life.
This article provides general information and does not replace veterinary care. If you notice signs of illness in your cat, contact a vet.
Frequently asked questions
Does blood in a cat's urine mean cancer?
No. The same symptom can occur with idiopathic cystitis, stones or bacterial infection, for example. Recurrent blood in the urine or a poor response to treatment needs reassessment. If urine cannot pass, the situation is urgent whatever the cause.
Can ultrasound confirm bladder cancer?
Ultrasound shows the location of a change and its effect on the urinary tract, but confirming the tumour type often requires examination of cells or tissue. Sampling is carefully planned because the tumour's location and the possibility of spreading cells affect the choice of method.
Is treatment available if the tumour cannot be removed?
It may be. Medicines, radiotherapy in selected circumstances and measures to improve urine flow can be considered. Treatment for pain, nausea and other symptoms continues regardless of whether the tumour can be reduced. Goals are matched to the cat's condition.
This article is for general information only and is not a guide to treatment. If you notice the first signs of illness, contact your vet.
Paw4care editorial team
Sources
- 2025 iCatCare consensus guidelines on lower urinary tract diseases in cats, International Cat Care, Journal of Feline Medicine and Surgery, accessed 2026-11-03.
- Lower urinary tract transitional cell carcinoma in cats: clinical findings, treatments, and outcomes in 118 cases, Journal of Veterinary Internal Medicine, ABVP, accessed 2026-11-03.
- Noninfectious diseases of the urinary system of cats, Merck Veterinary Manual, accessed 2026-11-03.
- Section 3: Tumour diagnostics and staging, American Animal Hospital Association, accessed 2026-11-03.
- 2023 AAFP/IAAHPC feline hospice and palliative care guidelines, AAFP / IAAHPC, Journal of Feline Medicine and Surgery, accessed 2026-11-03.
- Diagnostic testing: antimicrobial stewardship, AAFP / AAHA, accessed 2026-11-03.
- Litter boxes, The Ohio State University, accessed 2026-11-03.
- Management of bladder/prostate tumours for the general practitioner, MSPCA-Angell, accessed 2026-11-03.