Will new urine tests replace uncomfortable cancer diagnostic tests? - Cancer HealthLINK

Urinary bladder cancer is the fifth most common cancer in the U.S., but diagnosing the disease can be difficult. Unlike breast or prostate cancers, there are no widely accepted bladder cancer screening tests that are quick, easy and relatively pain free. Despite the promise of new tests, the best way to accurately diagnose bladder cancer remains performing cystoscopy and biopsy. No new urine test has yet approached the accuracy of cystoscopy.

"The best way to accurately diagnose bladder cancer remains performingcystoscopy and biopsy."

A crowded field of new tests
Because of the pain and expense incurred to the patient, scientists have long searched for a noninvasive test that offered sufficient accuracy. The market is now crowded with several new bladder cancer screening tests that detect tumor markers, but their use remains limited.

Those who require testing are either suspected of having bladder cancer or have had the cancer and are checking for recurrence. Symptoms of bladder cancer include:

visible blood in the urine;
pain during urination; and
frequent urination or feeling to go without results.

Anyone who experiences these symptoms should have a thorough exam to rule out other ailments. Cigarette smokers have a rate of bladder cancer two to three times higher than nonsmokers do. Exposure to certain chemicals also increases risk for developing bladder cancer later in life.

Cystostopy explained
For diagnosis, a urologist views the inside of the bladder through a cystoscope, which is like a telescope with a light on the end of it. During this procedure, which can be done in a physician's office, the inside of the bladder is examined. If any abnormalities are seen, more tests may be required to determine if the cancer is localized or has spread beyond the bladder.

About 80-85 percent of bladder cancer patients are diagnosed with early stage cancers that originate in transitional cells. These cells are found along the surface of the inside of the bladder, in the ureter tubes that go up from the kidneys, and in part of the kidneys. Treatment includes removing the tumor, allowing the person to keep the bladder. More invasive cancers require more extensive surgery and follow-up treatment.

The hope for these urine-screening tests is that they will save patients from undergoing repeat cystoscopy, which is uncomfortable and more expensive."

Checking for recurrence
Because even early bladder cancers recur, patients now must undergo frequent follow-up cystoscopies. The hope for these urine-screening tests is that they will save patients from undergoing repeat cystoscopy, which is uncomfortable and more expensive. The problem is that the new tests are not as accurate. The research is still showing too many false positives, which is where the test reads positive but there is no tumor.

Some of these urine tests, such as the NMP22, are already in use for bladder cancer follow-up. NMP22 was just approved by the U.S. Food and Drug Administration for use in initial diagnosis. Still, if cancer is suspected, the physician performs a cystoscopy to know with greater certainty that cancer is present. In my practice, I rely on flexible cystoscopy to follow patients and to make the diagnosis.

Use in screening
Much discussion has centered around using the urine tests to screen the general public for bladder cancer, much like the PSA test is used to detect prostate cancer or a mammogram is used for breast cancer. Because bladder cancer is much less common, I think you would have to limit the screening to people who have symptoms or are at risk for bladder cancer. So until the specificity and accuracy of these tests improve, I don't anticipate these urine tests will replace cystoscopy.

Dr. John Colberg is a urologist at Yale-New Haven Hospital and an assistant professor of surgery and director of uro-oncology at the Yale University School of Medicine.

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