New Urine Test Helps Find Bladder Cancer Recurrences
Article date: January 23, 2006
Inexpensive Test Improves Accuracy of Standard Follow-up
Summary: A simple urine test may help doctors find more relapses in people who have had bladder cancer, according to a new study. The test was used along with cystoscopy, a visual exam of the bladder using a long lighted tube. Together, the two tests found 99% of recurrences, researchers reported in the Journal of the American Medical Association.
Why it's important: People who have had bladder cancer are at very high risk of getting it again. There are about 500,000 bladder cancer survivors in the US, the researchers note. Most survivors have to be checked for a relapse every 3 to 6 months for the first few years after their initial treatment, and every year after that. Cystoscopy is the main way to look for recurrences, but it can't always find all of them. As a backup, doctors usually use urine cytology, a lab analysis that looks for cancer cells in urine. But this test also misses many cancers.
Patients and doctors need better ways to find bladder cancer recurrences early so they can be treated promptly. If a relapse is caught early, the patient has a better chance of surviving, said lead study author H. Barton Grossman, MD, professor of urology at the University of Texas M.D. Anderson Cancer Center.
What's already known: The new urine test, called BladderChek, measures the protein NMP22. High levels may signal bladder cancer. On its own, the NMP22 test hasn't been very accurate at finding bladder cancers. But researchers thought it might be better than urine cytology at finding cancers that cystoscopy missed.
BladderChek has several advantages over urine cytology and other urine tests that are used to look for bladder cancer relapses. It can be done in a doctor's office and usually gives results within 30 to 50 minutes. It is also less expensive and less complicated than urine cytology, which must be performed by trained specialists in a laboratory. It is already approved by the US Food and Drug Administration for helping diagnose bladder cancer and for helping find relapses. The test's manufacturer, Matritech, Inc., was involved in designing, funding, and reviewing the current study.
How this study was done: The researchers recruited 668 bladder cancer survivors who were being followed-up at 23 facilities across the US. Before having cystoscopy, each patient gave a urine sample. Part of that sample was used for the BladderChek test, and part was used for standard urine cytology. The researchers gauged the cancer detection rate of each of the 3 methods alone, and of each urine tests combined with cystoscopy.
What was found: Bladder cancer was diagnosed in 103 patients. Cystoscopy was the most accurate test, finding 94 of those cancers (91%) all by itself. The BladderChek test alone found only 51 cancers. But BladderChek combined with cystoscopy found 99% of the cancers. In fact, the BladderChek test found 8 of the 9 cancers that cystoscopy missed.
"We depend on the urine test to show us whether there's a possibility of cancer that we're not seeing with the scope," explained Barry Stein, MD, a co-author of the study and professor of urology at Brown Medical School in Rhode Island. "If the result is positive and you didn't see anything from the cystoscopy, you would check to see if you missed something."
Urine cytology also improved the performance of cystoscopy, but not by as much. It found only 3 of the 9 cancers cystoscopy missed. Together, the 2 tests found 94% of cancers, but that improvement was statistically no better than cytoscopy alone. Urine cytology alone found just 12 cancers. That's unusually poor performance for urine cytology, said Samuel Cohen, MD, PhD. He's a professor of oncology and chair of pathology and microbiology at the University of Nebraska Medical Center and a member of the panel that wrote the bladder cancer treatment guidelines for the National Comprehensive Cancer Network. He was not involved in the new study.
The study did not look at what happened to the patients after their relapse was detected.
The bottom line: The results of this study suggest the BladderChek test could be a useful tool for improving detection of bladder cancer recurrences and reducing the cost of follow-up care, the researchers say. It also raises some intriguing questions about whether it might be possible to find these recurrences earlier, said Len Lichtenfeld, MD, deputy chief medical officer for the American Cancer Society. He was not involved in the study.
"If [this test] were able to pick up a recurrent cancer before it could be seen," he said, "would that mean that some of the more aggressive cancers could be treated more effectively, with a greater rate of long term survival? We know that the longer a recurrence of bladder cancer is present, the more difficult the situation for the patient. So, earlier detection of a recurrent bladder cancer translates into better treatment."
But this study, while promising, isn't enough to say for certain that the BladderChek test is better than urine cytology, Cohen said. It's also not enough to tell whether this new urine test really can improve outcomes for patients by finding their cancer earlier. For that, researchers need to carry out head-to-head comparisons (randomized trials) of this test and other bladder cancer detection tests that also look at long-term patient results. The study authors call for such work in their paper. In the meantime, Grossman warns that the BladderChek test should be used only together with cystoscopy, not instead of it.
Citation: "Surveillance for Recurrent Bladder Cancer Using a Point-of-Care Proteomic Assay." Published in the Jan. 18, 2006, Journal of the American Medical Association (Vol. 295, No. 3: 299-305). First author: H. Barton Grossman, MD, University of Texas M.D. Anderson Cancer Center.
Reviewed by: Members of the ACS Medical Content Staff
ACS News Center stories are provided as a source of cancer-related news and are not intended to be used as press releases.
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