Bladder & Prostate Tumors
The most common tumor affecting the bladder and urethra of dogs and cats is a transitional cell carcinoma, or TCC as it is more commonly known. The tumor most commonly arises from the wall of the bladder or urethra. Genetic and exposure to pesticides and insecticides had been associated with tumor development in some patients. Scottish Terriers has a known genetic predisposition. The most common tumor affecting the prostate is a prostatic carcinoma. Although bladder and prostate cancers are malignant, they typically do not to spread until they are advanced.
Symptoms:
Stranguria, or straining, to urinate and bloody urine are the most common symptoms. Some patients have to urinate more frequently (unable to urinate as readily and have to go more often as a results) or in rare cases some patients present with a complete inability to urinate.
Testing:
Blood work may reveal increased kidney values if the obstruction is severe. In most patients, the blood work is normal. Urine results are variable but may show blood, white blood cells, infection and in some cases tumor cells themselves.
X-rays are often unrewarding in the diagnosis of bladder and prostate cancer, but are important for excluding bladder stones as the cause of the symptoms.
An ultrasound, or sonogram, is the preferred method to diagnose tumors in the urinary system. An ultrasound can show tumors arising from the bladder. The appearance of the tumor often resembles a mountain range inside the bladder. An ultrasound can also show thickening of the urethra. Bladder stones are easily recognized on an ultrasound and can be distinguished readily from bladder tumors.
Cystoscopy, or scoping of the bladder, can directly demonstrate a tumor and can facilitate a biopsy of a mass if present.
Treatment:
Surgical removal of the tumor is ideal, but is often difficult because of location. Chemotherapy has been shown to slow the tumor growth, but often does not shrink or eliminate the tumor. Piroxicam, an arthritis medication, has been shown to slow tumor growth and in some patient's halt tumor growth.
New procedures for bladder and prostate tumors have been adapted from humans. Stents are frequently placed in clogged arteries of the heart and can now be used for bladder and prostate cancer in dogs and cats. The size and location of the tumor are important when planning a stenting procedure. Some tumors are more amenable to stenting than others. Because dogs range in size from a few pounds to well over 100 pounds, particular measurements must be performed to determine the appropriate size stent. With the patient under anesthesia, a stent can then be placed under fluoroscopy (moving x-ray) without any surgical incisions. Stents immediately eliminate the obstruction created by the tumor. Possible complications include: transient incontinence and bloody urine. Permanent incontinence is rare and occurs in less than 15% of patients. Stenting has equal if not greater success than chemotherapy alone. Stenting is now considered the treatment of choice for many patients since it is minimally invasive and immediately improves the patient's quality of life.