Nuclear Matrix Protein 22 in Voided Urine Cytology Efficacy in Risk Stratification for Carcinoma of Bladder

Background To investigate the nuclear matrix protein NMP22 in voided urine for detection of malignancy in patients with risk factors of symptoms of bladder cancer. Methods January 2009 to December 2012, participants included 1,331 patients at elevated risk for bladder cancer due to factors such as history of smoking or symptoms including hematuria and dysuria, patients at risk for malignancy of the urinary tract provided a voided urine sample for analysis of NMP22 protein and cytology prior to cystoscopy. The diagnosis of bladder cancer, based on cystoscopy with biopsy, was accepted as the reference standard. The performance of the NMP22 test was compared with voided urine cytology as an aid to cancer detection. Testing for the NMP22 tumor marker was conducted in a blinded manner. Results Bladder cancer was diagnosed in 79 patients. The NMP22 assay was positive in 44 of 79 patients with cancer (sensitivity, 55.7%, 95% confidence interval (CI), 44.1-66.7%), whereas cytology test results were positive in 12 of 76 patients (sensitivity, 15.8%; 95% CI, 7.6-24.0%). The specificity of the NMP22 assay was 85.7% (95% CI, 83.8-87.6%) compared with 99.2% (95% CI, 98 initial endoscopy, including 3 that were muscle invasive and 1 carcinoma in situ. Conclusion The noninvasive point-of-care assay for elevated urinary NMP22 protein can increase the accuracy of cytoscopy, with test results available during the patient visit.