Emerging Utility of Urinary Cell-free Nucleic Acid Biomarkers for Prostate, Bladder, and Renal Cancers.

CONTEXT: By 2020 the estimated incidence of genitourinary (GU) cancers (prostate, bladder, and kidney) will be over 2 million worldwide and responsible for ∼800 000 deaths. Current diagnosis and monitoring methods of GU cancer patients are often invasive and/or lack sensitivity and specificity. Given the utility of blood-based cell-free nucleic acid (cfNA) biomarkers, the development of urinary cfNA biomarkers may improve the sensitivity of urine assays utilizing urine sediment for GU cancers. This review of urinary cfNA in GU cancers identifies the current stage of research, potential clinical utility, and the next steps needed to enter clinical use. OBJECTIVE: To critically evaluate the literature of urinary cfNA in GU cancers for clinical utility in diagnosis, screening, and precision medicine. Furthermore, the strategy for future efforts to discover potential new urinary cfNA biomarkers will be described. EVIDENCE ACQUISITION: A PubMed database (2006 to current) search was performed according to Preferred Reporting Items for Systemic Review and Meta-analysis using key Medical Subject Headings terms. Additional studies were obtained by cross-referencing from the literature. EVIDENCE SYNTHESIS: The collective research publications in urinary cfNA of GU cancers present a promising alternative liquid biopsy approach compared with blood biopsies and urine sediment, particularly for early-stage GU diseases. CONCLUSIONS: Urinary cfNA as a liquid biopsy holds potential for a more sensitive alternative to blood biopsies and urine sediment-based tests for clinical use in GU cancers. Not only does urinary cfNA offer advantages including the potential for more frequent testing, monitoring, and home use, but also has applications in early-stage GU cancers. PATIENT SUMMARY: In this review, we evaluated the current status of urinary cell-free nucleic acid in genitourinary cancers. We identified the potential advantages of urinary cell-free nucleic acid over blood and urine sediment and its clinical use in genitourinary cancer