gms | German Medical Science

Introduction: The limitations of cytology and cystoscopy in the diagnosis of bladder cancer (BC) have led to the development of new urine tests for the early detection of BC. The aim of this study was to compare the diagnostic value of the mRNA based Xpert BC Monitor and the DNA methylation based Bladder Epicheck in patients under follow-up.

Methods: 76 patients (mean age 77 yrs) under follow up for NMIBC were studied prospectively. Samples were analyzed with the Bladder Epicheck Test, the Xpert BC Monitor and voided urinary cytology. Subsequently, the patients underwent cystoscopy and if cystoscopically positive, a TURB.

For the Bladder Epicheck Test a software calculates the EpiScore, a number between 0 and 100 representing the methylation level of the sample. If the EpiScore is equal or above 60 it is considered positive. The results of the Xpert BC Monitor are interpreted by the GeneXpert^® Instrument System and given as LDA totals and Analyte Results on the Test Report. A cut-off is set at a LDA of >0.5.

Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of Bladder Epicheck, Xpert BC Monitor and cytology were calculated using cystoscopy/histology as gold standard.

Results: Of the 78 pts 12 (15.4%) had to be excluded due to insufficient DNA in the Bladder Epicheck Test.18 out of 66 remaining patients had histologically verified BC of the bladder. 48/66 patients were negative cystoscopically and/or histologically. Of the 18 patients with BC 12 (66.6%) were found positive for Bladder Epicheck, 10 (55.5) for Xpert BC Monitor and 6 (33.3%) for cytology. The sensitivity of Bladder Epicheck increased from 60% for low grade (LG) to 87.5% in high grade (HG) tumours, for Xpert BC Monitor from 50% to 87.5%, respectively. Specificity was 77.1% (37/48) for Bladder Epicheck, 72.9% (35/48) for Xpert BC Monitor and 97.9% (47/48) for voided urinary cytology.

Conclusions: Bladder Epicheck is superior to Xpert BC Monitor in sensitivity and specificity. The sensitivity of both tests was significantly higher than for cytology but none of the both tests was able to reach the high specificity of cytology. Xpert BC Monitor is easy and fast to perform while the Bladder Epicheck requires dedicated technicians and is more time consuming. Both tests could be, however, of interest as an additional tool in the follow up of patients with NMIBC, taking advantage of the high specificity of cytology and allowing to reduce the number of cystoscopies.