Researchers at the University of Texas M. D. Anderson Cancer Center tested the NMP22 tumour marker assay in 1,331 patients at high risk for bladder cancer. Researchers determined through cystoscopy that 79 of the 1,331 patients examined had bladder cancer. The NMP22 assay was positive in 55 percent of the cases while the conventional cytology test detected about 16 percent of malignancies.
This demonstrated that the NMP22 test was significantly more sensitive than cytology, or the conventional laboratory test, says H. Barton Grossman, M.D., professor in M. D. Anderson's Department of Urology and the study's lead author. "Our challenge is to improve the detection of bladder cancer," says Grossman. "This test is easy and may save lives."
He cautions, however, that NMP22 should not be used alone to detect bladder cancer, but should be combined with cystoscopy to provide an accurate diagnosis. "No single procedure is 100 percent sensitive, so a combination of procedures is recommended," Grossman says.
Grossman led a team of researchers at M. D. Anderson and 23 academic, private practice, and veterans' facilities in ten U.S. states who enrolled patients into the clinical trial that examined the effectiveness of these different diagnostic tests.
The alternative cytology test looks for abnormal cells in the urine and must be sent to outside laboratories for evaluation. Patients may wait as long as a week to receive these results, according to Grossman, while the results of the NMP22 test can be read within 30 to 50 minutes in the doctor's office.
Although NMP22 was more sensitive in this study, cytology was more specific (99 percent versus 86 percent), meaning that the number of false positives was higher for the NMP22 test. Still, the authors say "the high specificity of cytology is offset by low sensitivity, ambiguous test results, expense, and time lag to obtain reports."
MEDICA.de; Source: University of Texas M. D. Anderson Cancer Center