Objectives: This study was designed to determine the clinical usefulness of the Nuclear Matrix Protein 22 (NMP 22) Test for the detection of bladder cancer in comparison to urine cytology.
Methods: One hundred sixty-four patients suffering from or being suspicious for bladder cancer and 64 healthy controls participated in a prospective study. Freshly voided spot urine samples were taken for cytological examination and determination of NMP 22-levels by enzyme-linked immunoassay.
Results: Sensitivity to the NMP 22 Test according to the tumor grading was (results of cytology in parentheses): GI 25.0% (20.0%), G2 68.2% (59.1%), and G3 100.0% (66.7%); overall sensitivity was 62.5% (45.0%). Sensitivity according to superficial bladder cancer was 46.7% (36.7%), and to invasive bladder cancer 90.0% (70.0%). Specificity was 65.9% (88.9%).
Conclusions: NMP 22 is a reliable tool for detecting invasive bladder cancer. Results for the well-differentiated superficial bladder cancer occurring frequently are as poor as those obtained with cytology. In addition, benign lesions such as urolithiasis or urinary tract infection lead to false positive results. Therefore, cystoscopy has to be performed when trying to detect and follow-up bladder cancer.