Bladder and urethra tumors—what could be the cause?

Tumors of the urinary bladder or urethra are relatively rare in dogs, but are often malignant. In most cases, they are transitional cell carcinomas. Older female dogs are primarily affected. A higher incidence has been observed in Scottish Terriers, Airedale Terriers, West Highland White Terriers, and Beagles.

INHALT
Cause and origin Symptoms Diagnosis Treatment Forecast
Cause and origin

Transitional cell carcinoma develops from degenerated cells in the constantly renewing mucous membrane lining of the bladder or urethra. Undetected, untreated, or chronic bladder infections can therefore trigger tumor development. However, the exact cause of cell degeneration remains unclear.

Diagram of the urinary system in dogs
1 Kidneys | 2 Ureters | 3 Bladder | 4 Urethra
Symptoms

In most cases, clear symptoms of the disease are only noticed at an advanced stage. Initially, the symptoms resemble those of a bladder infection, and the two conditions are therefore often confused. Affected animals show difficulty or pain when urinating, frequent urination in small amounts, bloody urine, and, as the disease progresses, weight loss. If the tumor has already spread to the lungs, liver, or even bones, general discomfort or lameness may also occur. If the tumor blocks the urinary tract, urine accumulates and can lead to life-threatening kidney damage. If the animal suddenly stops urinating, a veterinarian must be consulted immediately.

Diagnosis

Due to the identical symptoms, a urinary tract infection is often diagnosed initially and treated accordingly. However, if treatment only leads to a short-term improvement and the symptoms continue to recur, further examinations should be carried out. An ultrasound examination is very well suited to visualising the bladder wall and the size and location of a possible tumour. X-ray examinations with contrast medium injected into the bladder can provide information about its filling status and any changes in the wall.

Endoscopic examination, also known as cystoscopy, allows your veterinarian to look directly inside the bladder and urethra. This enables them to identify narrowings, bleeding, or growths and take tissue samples directly. However, this examination should only be performed by a specialist. An accurate diagnosis and determination of the exact type of tumor can only be made with the help of a biopsy (removal of a tissue sample), which can be performed either surgically or endoscopically via the urethra. To determine whether the tumor has already spread to other organs, it is also advisable to perform X-rays of the chest, a comprehensive ultrasound examination of the abdominal cavity, and appropriate blood tests.

Treatment

In cases of urethral narrowing and difficulty urinating, catheterization of the urethra can be used as a first-line treatment to ensure that the animal can urinate without pain. The possibility of surgical removal depends greatly on the location and size of the tumor and how well it is separated from healthy tissue. Due to the often late discovery and invasive growth of bladder tumors, complete removal is therefore not possible in many cases. Parts of the tumor can be removed by laser treatment during a cystoscopy.

In the case of inoperable tumors, and especially if metastasis (spread) has already occurred, special chemotherapeutic agents are used to curb tumor growth. In addition, painkillers and anti-inflammatory drugs may be used depending on the extent and severity of the disease.

Forecast

There is no prospect of a cure, particularly in the case of malignant bladder tumors, and the prognosis is therefore generally poor. However, with the help of modern medication, the affected animal can still enjoy a relatively pain-free and comfortable life for a certain period of time. The prognosis depends largely on the type, location, and extent of the tumor, the time of diagnosis, and the potential for metastasis.