Bladder cancer is an increasingly common phenomenon, particularly among male smokers aged 55 and older. More than 70,000 Americans1 are diagnosed with bladder cancer yearly, and that number is expected to continue to rise. When detected early, bladder cancer is highly treatable with chemotherapy, radiation therapy, and surgery. Urodynamic testing is one way that bladder cancer can be detected when lower urinary tract symptoms are experienced.
There are three main types of bladder cancer: urothelial carcinoma, squamous cell carcinoma, and adenocarcinoma. Urothelial carcinoma (also known as transitional cell carcinoma) is most common, comprising approximately 90% of all bladder cancers. Squamous cell carcinoma makes up approximately 4% of bladder cancer cases, while adenocarcinoma accounts of 2% of bladder cancers.
The most common symptom of bladder cancer is blood in the urine. Hematuria might occur frequently, or intermittently. Other, less common, symptoms include urinary irritation, frequent urination, inability to urinate, a sudden urge to urinate, and incontinence.
The most prevalent risk factor for bladder cancer is smoking, particularly among males (this study2 delves into the root cause of bladder cancer). Smokers are 4 – 7 times more likely to develop bladder cancer than non-smokers, and men are 4 times as likely as women to develop this disease. Industrial exposure to aromatic amines, rubber, leather, textiles, and paint products may also increase a patient’s risk of developing cancer. Chronic dehydration in addition to the diabetes medication Actos and dietary supplements containing aristolochic acid3 have also been shown to increase a person’s risk of developing this disease.
Urodynamic testing occurs in two different ways for the diagnosis of bladder cancer. Most commonly, urodynamic testing is performed in order to rule out other causes of lower urinary tract symptoms, such as an enlarged prostate or interstitial cystitis. However, there are two urodynamic tests that are specifically performed for positive identification of bladder cancer, including videourodynamics (cystography) and testing the compliance of the bladder.
Compliance refers to the bladder’s ability to stretch its walls in order to accommodate increasing volumes of urine. A normal bladder will freely stretch and distend when filled, and only a slight increase in bladder pressure will be experienced at maximum capacity. Low compliance indicates an abnormality within the detrusor muscles to stretch while also maintaining low pressures within the bladder. Bladder cancer, interstitial cystitis, and radiation cystitis may cause low bladder compliance as well.
To test compliance, a complex cystometrogram4 is performed. During this test the behavior of the bladder and sphincter will be examined, as well as bladder capacity and pressure. When diagnosing bladder cancer, the main reason to perform a cystometrogram is to measure bladder compliance in relation to bladder pressure.
To perform a cystometrogram a catheter is inserted into the patient’s urethra and then directly into the bladder. The bladder will be filled with a sterile saline solution while the filling pressure is measured. The patient is asked to report sensations such as pain, urge to urinate, and feelings of bladder fullness. The bladder will then be voided and the appropriate pressures will again be measured. This procedure takes approximately 15 – 20 minutes to perform.
A second type of urodynamic test performed in the diagnosis of bladder cancer is videourodynamics, also called cystography. To date, cystoscopy has been widely considered the “gold standard” for bladder cancer diagnosis; however, there are functional difficulties with this test. For instance, male patients make up the majority of bladder cancer cases, yet the characteristic bending and flexibility of the male urethra can make this test difficult to perform. Therefore, cystography is a better option, and also carries a lower chance of complications, such as infection.
During a cystographic test a urinary catheter is used to fill the bladder with radiocontrast. X-ray imaging is performed while the patient voids his or her bladder up to three times. For potential bladder cancer patients, cystography and virtual cystoscopy5 can be used to visualize urinary tumors and extravesicle extensions. When staging the tumor, cystography is mandatory. Cystography takes approximately 60 minutes to perform. Because of the sensitivity of these techniques, as well as how well-understood they are among urologists, bladder cancer and urodynamic testing go hand-in-hand.
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If you found the above article useful you may want to check out our post on Neurogenic Bladder and Urodynamics: http://info.bhnco.com/blog/neurogenic-bladder-and-urodynamics
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