Digital PCR-Based Uromonitor for Molecular Detection of Bladder Cancer: A Multicenter Validation Study Comparing Quantitative PCR and Urine Cytology.

Abstract

Introduction: Non-invasive urine-based diagnostics for urothelial carcinoma of the bladder remain limited by suboptimal sensitivity. We validated a digital polymerase chain reaction (dPCR) Uromonitor^Ⓡ assay in a multicentre setting and compared it with an earlier quantitative polymerase chain reaction (qPCR) version and urine cytology.

Patients and methods: We analyzed 239 archived urine samples from a prospectively assembled biobank, including 123 patients with histologically confirmed urothelial carcinoma of the bladder and 116 with benign findings. The dPCR panel targeted TERT promoter and FGFR3 hotspot mutations. Historical qPCR data and contemporaneous urine cytology served as comparators. Sensitivity, the prespecified primary endpoint, was compared head to head using McNemar's exact test. Receiver operating characteristic curves with area under the curve (AUC) comparisons and multivariable logistic regression were also performed.

Results: dPCR showed higher sensitivity than qPCR and urine cytology (75.6% vs 51.2% and 42.3%, respectively; both p < .001) while maintaining 94.0% specificity. Positive and negative predictive values were 93.0% and 78.4%, respectively, and overall accuracy was 84.5%. The AUC for dPCR was 0.848, exceeding qPCR by 0.122 (p = .001) and urine cytology by 0.188 (p < .001). dPCR positivity was independently associated with histologically confirmed disease (odds ratio 38.9, p < .001). Diagnostic performance remained consistent across grade- and stage-based subgroup analyses.

Conclusion: These findings support dPCR as a robust non-invasive diagnostic adjunct under conservative analytical conditions and justify further large-scale prospective multicentre validation in clinically representative populations undergoing bladder cancer surveillance to define its role in risk=adapted evidence-based diagnostic pathways and inform future implementation studies in clinical practice.