Validation of a Molecular Urine Test for the Detection of Bladder Cancer Recurrence - Expert Commentary

Frequent long-term monitoring is required for non-muscle-invasive bladder cancer (NMIBC) patients due to the high rate of recurrence. White light cystoscopy (WLC) and urine cytology are widely used in surveillance methods. Although urine cytology has high specificity (SP), it has low sensitivity (SN) and negative predictive value (NPV). WLC is an invasive and expensive method that lack SN for flat lesions such as carcinoma in situ (CIS). A non-invasive surveillance method with a high SN, NPV is needed to detect NMIBC recurrences.

A new study published by Valenberg et al. in European Urology examined the performance of Xpert, a newly developed urine test that measures five mRNA targets which are over-expressed in NMIBC (ABL1, CRH, IGF2, UPK1B, and ANXA10). The investigators compared the performance of Xpert in detecting non-muscle-invasive bladder cancer recurrences compared to cytology and UroVysion Fluorescence in situ hybridization test. 

The study included 239 patients who were previously diagnosed with NMIBC. The mean age was 71, 80% were males, 22% never smoked, and 64% had previous intravesical therapy. Patients had Xpert, cytology, and UroVysion testing using voided pre-cystoscopy urine samples. Xpert had overall SN of 74% (95% confidence interval [CI]: 60–85) and 83% (95% CI: 64–93) for high-grade (HG) tumors. It had an overall NPV of 93% (95% CI: 89–96) and 98% (95% CI: 94–99) for HG tumors. It showed an overall SP of 80% (95% CI: 73–85) and 95% in non-NMIBC individuals (95% CI: 93–97). Xpert SN and NPV were higher compared to cytology and UroVysion. 

Based on these results, the investigators concluded that Xpert had an improved NPV compared with UroVysion and cytology in patients who are being followed for NMIBC recurrences. Prospective validation of these results in real-world settings and a cost-benefit analysis of this test are needed. 


Written by: Bishoy M. Faltas, MD, Director of Bladder Cancer Research, Englander Institute for Precision Medicine, Weill Cornell Medicine

Reference: 
Valenberg FJPV, et al. Prospective Validation of an mRNA-based Urine Test for Surveillance of Patients with Bladder Cancer.Eur Urol. 2018 Dec 12. pii: S0302-2838(18)30959-X. doi: 10.1016/j.eururo.2018.11.055. [Epub ahead of print]
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