A simple in-office urine test may help doctors find more bladder cancer recurrences than traditional urine cytology, researchers report in JAMA (2005;295:299–305). The test, called BladderChek, measures levels of NMP22, a protein known to be elevated in urine of people with bladder cancer. When combined with cystoscopy, the two tests detected 99% of recurrences, according to a team led by researchers from the University of Texas MD Anderson Cancer Center.

“A test like the NMP22 assay, which is accurate and easy to administer, I believe, will help identify and treat patients earlier, when they have a better chance for a good outcome,” said lead study author H. Barton Grossman, MD, Professor and Deputy Chairperson of the MD Anderson Cancer Center Urology Department.

The study involved 668 patients with a history of bladder cancer who were being followed up for recurrences at 23 clinical sites in nine US states. Each participant gave a voided urine sample before undergoing cystoscopy. Part of the urine sample was used for traditional cytology, and some was used for the BladderChek test. The researchers compared the detection rates of each method alone and of each urine test combined with cystoscopy. The test's manufacturer, Matritech, Inc., was involved in designing, funding, and reviewing the study.

Bladder cancer was diagnosed in 103 patients. Cystoscopy was the most accurate test, finding 94 of those cancers (sensitivity = 91%) on its own. The BladderChek test alone found only 51 cancers, but those included eight of the nine cancers missed by cystoscopy. BladderChek combined with cystoscopy found 102 of the 103 cancers (sensitivity = 99%), significantly more than cystoscopy alone (P = 0.005).

Urine cytology also improved the performance of cystoscopy, but not by a statistically significant amount (P = 0.08). It found only three of the nine cancers cystoscopy missed. Together, the two tests found 97 of 103 cancers (sensitivity = 94%). Urine cytology alone found just 12 cancers.

That's unusually poor performance for urine cytology, especially because many of the missed lesions were high-grade, said Samuel Cohen, MD, PhD, 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 study.

“I think these data are very interesting, especially given the size of the study and because they were using routine practice,” he said. “I was a little concerned that the cytology results were so poor. That's lower than I've seen in routine labs.”

The study authors attribute their poor results for urine cytology to variability caused by using multiple facilities rather than a single facility to interpret the samples. And they say the BladderChek test offers several advantages over urine cytology beyond the difference in sensitivity seen in this study.

Chief among them, the BladderChek test can be done in a doctor's office and requires no special equipment or training. Results are typically available in less than an hour. By contrast, urine cytology requires a specialized lab analysis, and results may take days to be returned. The BladderChek test is also less expensive than urine cytology, the authors say.

Because of its weak ability to detect cancer when used alone, Grossman says the BladderChek test should only be used in conjunction with cystoscopy, not as a replacement for that procedure. He and his coauthors call for randomized trials to more fully assess the potential impact of the new urine test on early detection of recurrences, patient survival, and human and financial costs to the health care system. 

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Figure  . A simple in-office urine test could help detect bladder cancer recurrences when used with cystoscopy.

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