Can urinary biomarkers replace cystoscopy?

PURPOSE: Diagnosis and follow-up in patients with non-muscle invasive bladder cancer (NMIBC) rely on cystoscopy and urine cytology. The aim of this review paper is to give an update on urinary biomarkers and their diagnosis and surveillance potential. Besides FDA-approved markers, recent approaches like DNA methylation assays, mRNA gene expression assays and cell-free DNA (cfDNA) are evaluated to assess whether replacing cystoscopy with urine markers is a potential scenario for the future.

METHODS: We performed a non-systematic review of current literature without time period restriction using the National Library of Medicine database ( https://ww.pubmed.gov ). The search included the following key words in different combinations: "urothelial carcinoma", "urinary marker", "hematuria", "cytology" and "bladder cancer". Further, references were extracted from identified articles. The results were evaluated regarding their clinical relevance and study quality.

RESULTS: Currently, replacing cystoscopy with available urine markers is not recommended by international guidelines. For FDA-approved markers, prospective randomized trials are lacking. Newer approaches focusing on molecular, genomic and transcriptomic aberrations are promising with good accuracies. Furthermore, these assays may provide additional molecular information to guide individualized surveillance strategies and therapy. Currently ongoing prospective trials will determine if cystoscopy reduction is feasible.

CONCLUSION: Urinary markers represent a non-invasive approach for molecular characterization of the disease. Although fully replacing cystoscopy seems unrealistic in the near future, enhancing the current gold standard by additional molecular information is feasible. A reliable classification and differentiation between aggressive and nonaggressive tumors by applying DNA, mRNA, and cfDNA assays may change surveillance to help reduce cystoscopies.