Back
|
BLADDER
CANCER
This information is provided by
Provet for educational purposes only.
You should seek the advice of
your veterinarian if your pet is ill as only he or she can correctly advise
on the diagnosis and recommend the treatment that is most appropriate for
your pet.
Note for Pet Owners: Topics on this Page:
|
Description
Cancer of the bladder is common in dogs but rare in cats.
Several different types of tumour may occur at this site, including (in alphabetical order):
- Adenocarcinoma
- Carcinomas (undifferentiated-dogs)
- Fibromas (dogs only)
- Haemangioma
- Haemangiosarcoma
- Leiomyoma
- Leiomyosarcoma
- Lymphoma
- Papillomas (dogs only)
- Rhabdomyosarcoma
- Sarcomas (undifferentiated - dogs)
- Squamous cell carcinoma
- Transition cell carcinoma - the most common bladder tumour in both cats and dogs
Cause
The underlying cause of bladder cancer is not known for most naturally occurring cases.
Some benign tumours eg fibroma and papilloma in dogs may develop as a result of chronic urinary tract disease and urolithiasis.Other risk factors reported for the development of bladder cancer in the dog include :
- Insecticidal dips
- Dogs living near to marshes
- Obesity
- Cyclophosphamide treatment
In cats and dogs advancing age is a major risk factor. Bladder tumours occur at an average age of 9.5 years in dogs and between 10-13 years in cats - except for lymphoma which occurs in young cats and rhabdomyosarcoma which occurs in young dogs and cats.
Breed Occurrence
Dogs : The following breeds of dog are reported to be at high risk to develop
bladder cancer :
- Airedales
- Beagles
- Collies
- Saint Bernards (rhabdomyosarcomas)
- Scottish Terriers
- Shetland Sheepdogs
Cats : There is no reported breed-associated risk
Signs
- Passing blood in urine
- Increased urinary frequency
- Difficulty passing urine
- Straining to pass urine
- Increased thirst
- Urinary incontinence
- Lameness - if the cancer has spread to bone (uncommon)
Complications
Cats : The majority of bladder tumours in cats are malignant, however unlike dogs, a significant number do not involve the trigone area and ureter, in which case surgical excision is more likely to be successful.
In both cats and dogs metastatic spread to distant organs eg lymph nodes and lungs make successful cure unlikely.
Diagnosis
Large tumours can be palpated in cats, but even these may be difficult to locate in dogs, and smaller tumours can not be felt. Diagnosis is based upon laboratory tests, imaging (eg positive, negative or double contrast radiographs or ultrasound) or visual inspection of the bladder wall.by cystotomy or cystoscopy..
Cancer cells may be identifiable in urine sediment - but this does require skilled training in cell cytology, and only about one-third of cases can be diagnosed by this method..
In most cases excision biopsy of the tumour is needed and the diagnosis is made on histopathological examination.
In reports of dogs (4 studies) 278 of 422 (65.9%) bladder tumours were transition cell carcinomas
Of 76 cats reported to have bladder cancer 65 (85.5%) were
malignant and 44 (57.9%)were transition cell carcinomas.
Treatment
Dogs: Surgical excision is the treatment of choice , but this can be difficult in many dogs as the tumours often involve the trigone area of the bladder and the urethra, and surgical excision may be impossible without sacrificing the ureters. Anastamosis of the trigome or ureters to the colon can result in serious complications including pyelonephritis (30-50% of cases) hyperchloraemic acidosis, stenosis of the ureter and incontinence.
Other treatments used in dogs include :
- Radiotherapy - complications are a problem and recurrence is common - even after high dose therapy
- Chemotherapy - has been used alone and in conjunction with radiation therapy but the most effective treatment for transition cell carcinoma has still to be determined. If surgical treatment is impossible chemotherapy with cisplatin, carboplatin, mitoxantrone or piroxicam would be the next best approach.
- There is some anecdotal evidence that some NSAIDs may delay progression
Cats : Surgical excision is the treatment of choice for bladder cancer in cats.
In both dogs and cats surgical excision of benign tumours can be
curative.
Prognosis
The prognosis is good for benign tumours that can be removed successfully,
but the prognosis is guarded for malignant tumours. Long term problems
Local recurrence, metastatic spread to vital organs and urinary incontinence are common reasons for euthanasia following attempts at surgical treatment.
Updated January 2016
d>